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Go%[Industries INSTRUCT IONS TYPE FM-E, X, Z MAGNETOS - ENGINE ACCESSORIES OPERATION BELOIT, WISCONSIN 53511 SERVICE INSTRUCTIONS TYPE FM-E, FM-X, FM-XD, FM-XDE, FM-XE, FM-XF, FM-XFE, FM-XFZ, FM-XO, FM-XOR, FM-XR, FM-XV, FM-XVE, FM-XY, Fig. 1. Standard and Radio Shielded Magnetos GENERAL DESCRIPTION Fairbanks M o r s e S e r i e s X magnetos, Fig. 1, are-of the rotating magnet dcsign. thd basic principle consisting of inducing and continually reversing magnetic flux linen - - - -~-.!-.~-z ~ rnru an lnoucrlon c~o u .~ l.n l .s is accompusneo oy -.-.>.-~ rnp~ary rotating the permanent magnetic rotor through a stationiary field whieh'is the baais of the magnetic circuit. ..~ ~~~ ........ ~ ~ -.~.~ .~ ... A one, two, or four-lobe c u n actuates a b r e a k e r mechaniam periodically during each revolution of the r o t a r . Each t i m e the breaker points a r e separated by the magnetic rotor cam, an ignition spark i s produced. In the one-cylipd~rmagnetos this oc5uy.s .oncep e r revolutionof the rotor; In the two-cylinder magnetos the distributor rotor f o r m s an axial exteneion of the magnetic rotor and the breaker points a r e eeparated twice per revolutipn of the rotor by a two-lobe cam. Similarly, in tho type FM-XY four-pole magnktos, the distributor rotor forms an axial extension of the magnetic rotor. Since the cam of the rotor h a s four lobes, the b r e a k e r points separate four t i m e s p e r rcvolutian producing four igpition sparks. In the standard four-cylinder magnetos, a two-lobe cam i s used which produces two i ~ n i t i o nsparks per revolution of the magnetic rotor, In all such c a s e s an ignition spark i s furnished t o each hinh tension outlet, once f a r ekery two reva1utior;fi of the m&netic rotor. - . - In the-FM-XR6 and FMZ6 six-cylinder magnetos, a t w o lobe cam i s used which produces two ignition sparks p e r revolution of the magnetic rot0.r: A gear arrangement i s used t o connect the magnetic rotor with the distributor rotor which furnishes a s p a r k to each high tension outlet .-=.- ~~ ~ . ~ - ~ - A L -. . ... . ........ !- -.-~~ MAGNETO INSPECTION The entire magneto ahould he inspected for worn p a r t s every 1000 hours of operation. End Cap and End Cap Removal W h e n the usual inspection and s p a r k testa indicate poor magneto p w f o r m a n c e , the end cap and end cap cover. Fig. 2, if used, should be removed. Tag tho ignition cables to insure their p r o p e r replacement in the endcap: then remove each high-tension cable f r o m i t s socket. I n the type FM-E magnetos, t h e e n d cap cover m u s t ,b,c!,,;::': removed to. expose the high tension cable t e r m i n a l # bcr--j..::?;$. ,.. f a r e the lead S r e s can ba;embved. ~he;'r&oving .::::'':' end cap of the types EM-X4, FM:XR, FM-XOR;:.-?A!:~~!$;I$~:;F$ FM-XV magnetos, thc end cap cover mysf be..+SFb'$$&y:j;{T, and the distributor r o t o r taken off t h e . - e n d ; < 1 t > g x ~ ~ ~ 3 ~ $ ~ ~ ~ shaft before the end cap can b e removed. ', ,~??;. - the::.. .....-... L'r..r,:>:;.;...?:'..J ~,~.~:~ .... . .,.,..,. ; . , A . , . .,.;;.;i.<r;:~;;;: ::;;,' . . . . . . . . . . . . . . . . .., ,,,%, ,~ .c' FILE SECTIONS-TYPE FM-E, FM-X, FM-Z . . . . . ... . . <2,'., ~ s t r u c . ~. . .i3..:r.o?. .,~3,. ':: ~. ' ~ ~ Supersedes 3133 dated ~ u l ~ ; ' l $ i ~ '. I:,.: <; March. 1973 --Pegc 2 10 .truct:on Service Instructions .'$-I a r m spring. Thcn slide off the fulcrum pin snap ring and lift the breaker a r m df the fulcrum pin. Take out the two contact support locking screws, lockwashers, and plate washers, and lift the support bracket f r o m the bearing support. Inspect the breaker points fur pitting o r pyramiding. A small tungsten file or fine stone should be used to resurface the points. If the points are badly worn a r pitted they should he replaced. When the breaker points have been resurfaced or replaced he s u r e to adjust them to their propar claarnnce of 0.015 f .OOZ in. a t Ngb polnt of f i ~ ~ the following ~ ~ manner i : cam. ' Loosen the two contact support locking screws. Insert a aerewdrivor i n the horizontal slot at the bottom of t h e contad support and move it by pivoting the tool between the two small bosses on the bearing support until the breaker points are adjusted t o the correct clearance. Lack the assembly in place by tightening the locking screws: then take a final measurement of the breaker Oil point gap after thc locking acrcws a r e tightened. film should,be removed from t h e breaker points by using a brush and a small quantity of petroleum solvent. Fig. 2. End Cap and High Tension Cdble Tarminala Carbon Brush and Spring Magnetos for engines with two o r m o r e cylinders have a carbon brush and spring assembly in the center of the end cap cover, Fig. 3. Multi-cylinder radio-shielded magnetos have a distributor block in the end cap which contains a carbon brush,and spring. Examine the brush and replace it if worn o r damaged. The brush should move freely in i t s holder and should be under slight spring pressure. The high tension lead and suppressor assembly can he unscrewed from the distributor block for inspcction. cleaning or replacement. Bearing Support with and without Point Set, Condenser and Cam Wick Fig. 4. Breaker Arm, Support Bracket and Points Condenser Breaker paints ahould be checked and adjusted every 500 hours of operation. Remove the standard condenqer from the magneto byun screwing the condenser mounting screw. Fig. 5. To remove the feed-tbru condensers on thc FM-E6, FM-XE. FM-XFE, FM-XVE, FM-XYE and FM-XZE m u l t i p l e cylinder radio-shielded magnetos, take out the two candenasr mounting screws. T o remove the breaker point aasembly, Fig. 4. take out the breaker a r m terminal screw which releases the r o i l lead wire. condenser lead, ground contact, and breaker - Clean the condenser and lead wire with a dry cloth: do not damage t h e lead wire. Then inspect lead wire for damage. Tent the .condenser for open circuit on a reliable condenser tester or substitute an identical new condenser i n ita place. The capacity of the AX-M-R-2433 condenser is 0.17-0.23 mfd. The capacity of the S-X-Y Standard ... Radio Shielded with Distributor Block Fig. 3. Magnetos with Brush and Spring Feed-thru Condenser n P a ~ e I Instruction M3.1 servikc Inntructions nuuun PINION GEAR I Condenser nut shown Fig. 6. Two Typos of Bearing Supports, CW Rotation -2433 Condenser i s 0.28-0.36 mfd. The capacity of the L-V-2433 condenser i s 0.37-0.43 mfd. The canaeitv of feed-thru condensers is as follows: HX2433 0.28-0.. 36 mfd. JX2433 0.17-0.23 mfd, KX2433 0.28-0. 36 mfd ahd MX2433 0.28-0.35mfd. Teet the condenacr a t 440v d r for breakdown voltage. - . Bearing Support A s s m b l x Before removing the bearing support assembly, Fig. 6, be s u r e the breaker a r m terminal screw has been rcmoved. On types FM-X4. FM-XE4. FM-XF, FM-XFE. and FM-XZE, the magnstlc rotor gear must be removed bofore the hearing support assembly can be taken out of thc housing. Remove the magnetic rotor g e a r snap ring and draw off the g s a r using the pinion gear puller OMT76. Tho magnetic rotor gear pin can then be taken out. On later model magnetos the new style magnetic rotor gear (15952 can be easily removed after taking off the rotor gear snap ring. Then take the bearing support out of the magneto housing. Coil Fig. 6a. Use of OMT76 Magnetic Rotor Gear Puller - All FM-X Magnetos The removal of the coil in a l l magnetos will be e a s i e r if the magnetic rotor i s turned to place the magnets in a vertical position o r until t h e flux lock i s broken. The coil in magnetos which have no reduction gear. Fig. 7, between the magnetic r o t o r and the distributor rotor. can be easily removed f o r testing. Take out the breaker a r m terminal screw, remove the coil lead w i r e and the condenser. Loosen the coil bridge seteerews located on top of the housing at each side, then slide the coil out of the housing. The coil in a maghato whlch h a s the distributor rotor geared t o tbs magnetic r o t o r can be removed only after the bearing support assembly has been taken out of tho housing. Refer to paragraph Bearing Support Assembly. On types FM-E, FM-XR and FM-XOR magnetoa, if the bearing support i s hard to get out, remove t h e impulse coupling on flange nlaunting magnetos, and Liftout the.oil slinger baffle disc, replace the impulse coupling nut on tho rotor shaft, and strike the shaft a aharp blow. This will loosen the bearing support so it can be lifted out of the housing. The outer race of the rotor cam end bearing will remain in the bearing support. CCW Rotation Clean the coil lead wire with Idry cloth; do not damage the Lead wire. lnspoct t h o coil visually f o r cracks o r exposed windings which would be cause for discarding the Coil. Test the coil on a reliable t e s t e r . Impulae Coupling Although much s e r v i c e work can bc performed on the magnetowithout taking the impulse coupling off t h e rotor shaft, the removal of the magnetic rotor will necessitate complete removal of the coupling. We recommend that the coupling b e removed for cleaning and lubrication whenever m a j o r service work i s done on the magneto. An impulee coupling ia a mechanical device installed on the magnetic rotor shaft between the magneto and engine drive. Ita prime purpose i s t o intensify the ignition apark at low rotative speed, and to automatically r e t a r d the ignition spark during the engine atarting to eliminate backfire. C W Rotation Fig. 7. Bearing Support with and without Distributor G e a r T h s impulae coupling assembly, Ftg. 8, consiota of a shell, flat o r coiled d r i v s spring and coupling hub asacmbly with o r without pawl springs, which i a keyed to tha magnetic r o t a r shalt. The d r i v e spring has olio end engaged in thc longer slat in i h c coupling hub while the other end has a Loop formed which fits into the coupling shell. T h e coupling shell is.fitted into the drive member on the enginc d r i v e shaft. Page 4 I n ~ t r u d i o n.d3-1 - -- Service Instruction ~ i g .8. Coupling Components: H U ~ ,Drive Spring, and Shell Fig. 8a. When the engine i s operating at slow speed, the pawl in the coupling hub engages the stop pin i n the magneto housing, which prevents further movement of the magnetic rotor. As the engine continues to operate the shell winds up the drive spring. At the point in t h e engine cycle when the fuel mixture should be ignited, the pawl ie released by movement of the coupling shell, and snaps the magnetic rotar forward a t high speed through its firing cycle. As the engine speed increases, centrifugal farce withdraw8 the pawls to a position where they no longer engage the stop pin. In applications where the magneto opqrates in other than a horizontal position, t h e force of gravity cannot a d upon the coupling pawls during the starting period. T o cause the necessary s n g a g e m a a t a"tion, small e r e springs a r e attached to each coupling pawl. To remove the complete impulse coupling, take out the impulse coupling nut lockwire o r turn down the lugs of the impulse coupling nut lockwaeher; remove the i m pulse coupling nut and lockwasher. In the base mounted magnetos, remove the impulse outer shell screws, lift out the outer shell cupped washer and the outer shell felt washer. Remove the complete impulse coupling from t h e mag: net0 by using the OMT8 puller. If the tension appned by the puller does not loosen the coupling, tap the pull e r screw with a hammer, which will j a r the coupling loose f r o m the rotor shaft. When the coupling is removed, lift out the coupling outer shell flat washer used on base mounting magnetos. The coupling should he disassembled only by an experienced service station. In the event the shell comea loose from the hub when the coupling nut i s taken off, care must be exercised in r e r. (i.>,..* +., assembly. . Coupling butor rotor gear. remove the distributor shaft snap ring and slide the shaft and gear f r o m the hearing support, Fig. 9. Ball bearings a r e used in the FM-E, FM-XR, and FMXOR magnetos, T o remove the d i a t.r i b u t o r b e a r h g from these magnetos, take out the distributor ahaft snap ring. Place a piece of aoft lead on 'the bench, turn t h e bearing aupport over so t h e distributor shaft points downward, grip the bottom of the bearing support with both hands. and strike the end of the distributor shaft on the lead a fear t i m c s t o j a r the shaft loose f r o m t h e bearing. Distributor sleeve bearings may be pressed out of their respective bearing supports by means of the hand screw presa 370TD. and the distributor bearing tool TD2252A. T o remove the distributor b a l l bearing, take off t h e distributor bearing snap ring and p r e s s the bearing out of i t s support. Magnetic Rotor Types FM-X, FM-XV There a r e t h r e e types of magnetic rotors used in t h e seiies X magnetos: a two-pole rotor G t h block magnets; a two-pole rotor with b a r magnets perpendicular to the rotor axis; a four-pole rotor with a cylindrical magnet, Fig. 10. - Place the coiled end of the coupling spring i n the elot i n the shell in the correct rotation for the magneto: clockwise for CW rotation, covntcrclockwise ior CCW rotation viewed when the coupling shell i s turned up. Engage the straight end of the spring in the longer slot i n t h e coupling hub and turn the hub one full turn, then push the assembly together and install i t onto the magneto. Distributor Gear Assembly There a r e three types of distributor hearings used in FM-X magnetos. An oilitc slceve bearing o r a niedle bearing may be used in typee FM-X4, FM-XE, FM-XFZ FM-XYE and FM-XZE magnetos. T o r e m o v e the distri- Fig. 9. Uoarirlg Support with Distributor Gear Assenibly and Distributor Rotor service instructions Fig. 10. Twc-pole Rotor with Rlock Magnets. . Two-pole Rotor with Bar Magnets Placed Perpendicular to Rotor Axis With the impulse coupling and bearing support removed, take out the oil slinger baffle disc, found only on flange mounting magnetos with integral flange. Then remove tho rotor drive end seal outer washer by striking i t with a punch on thc shaft edKc. - This dishes the washer and permits easy removal. On m o r e recent models, lha rotor drive end seal outer waeher is made with one edge cut flat making i t oasy to insert tho point of a scre&driver and loosen tho washer. Discard the waaher after it has been removed from the magneto. Page 5 Instrurti6n ~ 3 - 1 . Four-pole Rotor with Cylindrical Magnet Remagnstiri~gMagnetic Rotor Due t o the sxccptIonal stability of the Alnico magnets usod in Fairbanks Morsa magneto., i t is recommended that the rotor be r s r m ~ n c t i z e donly when it h a s bean definitely determined that the ignition s p a r k i s bclow the required minimum value. Thc remngnetizinK vroceas invilvc. the use of mitablo oqutpmcnt i n d shoild b e undertaken in accordance with t h e foliowittg instructions. Magnetisation Lift out the rotor drivc end seal and t h e rotor d r i v e end scai inner wisher. Thts washer' is a loons fit but may be difficult to rcmove due to the adheaion of bearing grease. Finally, remove the magneto rotor shaft snap ring which i s found only on the types FM-X, FM-XD, FM-XDE, FM-XE. FM-XF, FM-XFE and FM-XZE magnetos. P r e s s the rotor out of the housing. P l a c e t h e asnembly in the adjustable proas d t h tho t a m end of t h e rotor shaft carcfuily centored in tho lntge hole of t h e base plate. Then place the brnss p r o t e c t i v c cap over the threaded end of the rotor shaft and apply an o v m p r e s sure by slowly turning tho drive screw. As soon a s the rotor i n pressed out of the drlvc end bearing it may be rcmovod f r o m the magneto housing. In magnetos that have the rotor drive end bearing r e taining waaher. this washer must be removed before tha hearing can be pressed out of the housing. The l e n e h of the magnetizing time depends oo tho type and strength of the charger. It is recommended that the rotors be given a minimum charge of 30soeonda, broken into two periods, o r "shots." Arrangements should bo made to place the rotor in tha magneto housing as soon as it is taken from t h e magnetizer. Two-pble Rotors Determine the polarity of t h e rotor and t h e magnetizer, Fig. 11. Place the magnetic pole of the rotor, which attracts t h e N pole of a compass, in contact with the magnetic pole of the chnrger whtch attracts €he S pole of the compass. By holding the rotor in the vicinity of a charger while i t is in operation, the attraction of unlike polea i s casily discernible. All rotors oreopt those for type IFM-XV magnetos a r c of the two-pole design and ohould be placed in the charging blocks a s described above. The large radii of the charging blocks should be used for rotora f r o m types FM-E, FM-XR and FM-XOR m a g n e t o B, and the small radii should be used for rotors f r o m type FM-X units. Four-pole Rotors Four-pole rotors, Fig. 12. used in type FM-XV magnctoe, m u s t bo remagnetized wlth special care. Thcsc rotors have large cylindrical magnets with the axis of the poles pnraltel to the shaft. The magnetising blocks muet be placed on the charger with m a d m u m surface contact. Insort the rotor i n tho drilled holes o i the magnetizing block with the keyway up. Drive End Ball Bearing Fig. 11. Magnetizing Standard Two-pole Rotor with Bar Magnets. To magnetize standard two-pole rotor with block magnets, u s e aamc setup hnt reverse charging blocks. Rclcaae the bearing snap ring with anap rlng pliers, and place the magneto in the hand Screw p r e s s 370TD. Put a braes protective cap over the center of tho bearing, Fig. 13. As tho screw i s turned down, contcr the assembly in the press. Apply p r e s s u r e evenly t o thc inner bearing r a c e until the Inner bsarxng r a c e and hall rr- Page 6 Inetruct~orlM3-1 loasen the old lubricant., Then inspect t h c b e a r i h g carefully. Replace any bearings that a r d frozen o r havc broken balls, needles, or excessive axial play. Repack each bearing with FMCO11 magneto bearing grease. Sleeve Bearings Oilite bearings, Fig. 16, found in scrvicoahle condition during magneto overhaul may be replaced after soaking them in turbine oil. Howaver. since these bearings are relatively inexpensive i t i s recommended that a new sleeve bearing beuscdwhen the magnetois reassembled. Fig. 15. SS Needle Bearing Fig. 16. Sleeve Bearing All other p a r t s should b e cleaned with a small, stiff brush moistened with a petroleum solvent. Inspect a l l castings and machined parts for chips, cracks, stripped or mutilated thread or other defectb.. Inspect a l l gears for chips, cracks, broken teeth: all bearing aurfaces and keyways and all springs f o r banding, cracking o r loss of tension. Replace any defective parts. REASSEMBLY OF MAGNETO If during the overhaul of the magneto the housing has been cleaned with any type solvcnt solution, be s u r e to remove any t r a c e s of the solution with water and finally remove any remaining water and foreign material with a MAGNETO FRAM Fig. 13. P r e s s i n g Ball Bearing Out of EIousing taining ring a r e pressed out. The outer bearing race will remain in the housing and may b e pressed out if desired. If the bearing i s of the non-separable type. the outer race driver must be used with 370TD band p r e s s to press the entire bearing out of t h e housing i' '4- L a:., / " - Ball and Needle Bearings Clean the grease out of the ball bearing, Fig. 14, and the needle bearings, Fig. 15, if used, by soaking them in a petroleum solvent, turning the bearing cage slowly to BALL BEARING R E INNER RACE Fig. 14. Separable and Non-soparable Ball B e a r b g s Fig. 17. Pressing Rotor Drive End Bearing into Housing Two-pole Rotor with l'erpenrliculsr LIar M a g n e t s . Four-pole Rotor witlr Cylindrical Magnet Fig. 18. P r e s s i n g Sleeve Bearing into Bearing Support P e t r o l e u m solvent. Then d r y t h e housing thoroughly bef o r reassembling t h e magneto. Rcplscement of Drivc End Bearing T > W C I FM-XI, Fh4-X2, FM-X4, FM-XE4 The d r i v e end ball bearing used in types FM-XI, FMXZ, FM-X4, and FM-XE4 magnetos, when cleaned, inspected, and repacked with F M C O l l magneto bearing grease, m a y b e replaced i n t h e housing, Fig. 17. Cent e r the bearing by hand, i n the housing, and place the P l a c e t h e bearing above housing i n t h e s c r e w p r e s s . the support block carefully centering i t with t h e bearing. Then t u r n down the d r i v e s c r e w of the p r e s s , placing the b r a s s cap between the drive screw and the aupport block. B e s u r e t h e a s s e m b l y i s perpendicular in t h e p r e s s b e f o r e forcing t h e bearing into t h e housing. R e place t h e magnetic r o t o r drive end bearing anap ring. Replacement of Sleeve Bearings P u s h t h e new sleeve hearing on t h e end of tool TD2252A and place t h e bearing support plate and t o a l i n the 370TD hand screw p r e s s i i n t h e s a m e position a e f o r removal, Fig. 18. Apply a n even. gradual p r e s s u r e , pushing t h e hearing into t h e bearing support until i t i s flush with the b r e a k e r side of t h e plate. When both the-magnetic t o t o r b e a r i n g l b c e t h e d i s t r i b u t i r bbaking'i'h types FM-XFZ, FM-X4, and FM-XE4 magnetos have been replaced, t h e bearing support i s r e a d y to be replaced i n t h e housing. P r e s s the distributor ball bearing into its r e c e s s , types FM-E, FM-XR. FM-XOR, using t h e 370TD p r e s s , and replace t h e distributor bearing snap ring. T h e n p r e s s the distributor shaft into place using the hand p r e s s . and replace t h e distributor ahaft snap ring. T h e b e a ? i i g support i s r e a d y to b c replaced i n t h e housing. Reasscmbly of Magnetic Rotor Typcs FM-XV, FM-XOR, F M - E P l a c e a new magnctic r o t o r bearing oil s e a l in thc d r i v e end recess of the rotar, and a new magnetic rotor s e a l T w n - p o l e Ilotnr with Black M a g n e t s Fig. 19. T h r e e T y p e s Magnetic Rotors Assembled i n Housing in t h e c a m end recess of t h e r o t a r for type FM-XVmagnetos, Fig. 19. Slide t h e bearing t h r u s t washer next to t h e m a g n c t i c r o t o r g e a r o n r a t o r s IOT lypea YM-XR, FM-XOR, and F M - E magnetos. Pl&cc t h o assembly t h e hand s c r e w p r e s a a n d with t h e r o t o r accurately aligned with t h e bearing race, preas t h e inner b e a r i n g r a c e onto tho r o t o r using t h e inner r a c e d r i v e r OMT82 as a n auxiliary toal. P r e s s the b e a r ~ n g race for t h e d r i v e end bearing of t y p e s FM-XR, FM-XOR, and FM-E magnetos onto the r o t a r until i t r e a c h e s t h e shoulder of t h e lamination assembly. P r e s s the races f o r the other b e a r i n g s onto t h e r o t o r as f a r a s the w a s h e r s and cork s e a l s will p e w i t . P l a c e t h e ball r e t a i n e r on tho inner hearing r a c e s and r e p l a c e the rotor and bearing into t h e housing. Replacement of Magnetic Rotor into Rousing Typcs FM-Xi. FM-XZ. FM-X4 The magnetic r o t o r types FM-XI, FM-XZ, FM-XF2 and FM-XE4 magnetos m u s t b e p r c s s e d into t h e housing, Fig. 20, using t h e 37OTD'acrcw p r e s s . P l a c e housing I" the p r e e s with t h e d r i v e end bcaring accuraloly cent e r e d o v e r the l a r g e hole i n b a s c plate. Than, with b r a s s cap o v e r c a m end of t h e r o t o r , p r e a s the rotor into t h e b e a r i n g until t h e shoulder of the lamination a e sembly touches the i n n e r race of drive end bearing. R e place thc r o t o r d r i v e end shaft snap ring i n i t s groove on Service Instruction w1U tlle marked tooth of the distrSbut6r gear. Fig, 22. when reasaambling n clockwise magneto the gears must rnealr ao that the tnothpaintetl red on the magnetic rotor will mesh between the two teeth on t h e distributor gear marked "C". On a counterclockwise magneto the r e d tooth on the magnetic rotor gear must mesh between tho two teeth m the distributor g e a r marked "A". Fig. 20. &placing Rotor Drive End Shaft Snap Ring Fig. 22. Gear Markings the rotor shaft; replace the rotor ahaft seal inner washer, rotor ehaft seal and rotor shaft s e d outer washer. Rotation of Coupling Drive Springs When replacing the magnetic rotor on the FM-0, FMXO, FM-XOR. FM-XY. FM-XV and .all magnetos with three piece ball bearings, end end play tolerance of the magnetic rotor between i t s bearings should be held below 0.007 inchea. Coil Replacement Before replacing bearing support, set the coil. FSg. 21,. in the housing. Tighten the two coil bridge sstacrews and seal them with a drop ar two of,gasket varnish. The coupling drive spring can be used f o r either rotation by simply turning i t over. Care must be taken to place the spring correctly in the shell. since incorrect assembly will damage the inside anchor end. Fig. 23. ~ 1 1 ~ s t r n t c s tho o o r r s c t location of drive springs in s e r i e s U coupling shslla. Catch t h e inner end of the drive spring i n the longer slot of the ooupling hub and complete t h e aaacmblybyrwinding the drive spring one full turn. P u s h t h e assembly together and key the coupling onto t h e rotor shaft. Replace the impulae coupling nut lockwasher, screw t h e impulse coupling nut into place, and turn up the lugs on the impulse coupling nut lockwasher. o r replace the coupling nut lockwire. if used. SPRING ANCHOR IN SHELL COUPLING DRIVE SPRIIM / CCW ROTATION Fig. 21. Cutaway of Molded Coil . Replrcemmt of Bearing Support Assembly and lntcrnnl T i d n g Replace the distributor shaft and gear assembly i n the bearing support of types FM-XFZ, FM-X4, and FM-XE4 magnetos and s e c u r e i t in placewith the distributor shaft snap ring. Fasten the bearing support assembly i n the housing. Replace the magnetic rotor gear pin and magnetic rotor gear. The former can be tapped into position by placing a hollow cylindrical tool, such a s the OMT82, over the c a m end o f t h e rotorwitlithe gear p a r tially i n place, and striking the cylindrical tool a few light taps. On later model magnetos the new type magnetic rotor can be easily assembled on the cam end of the magnetic rotor without special tools. A snap ring holds this gear onto the shaft. Care must bc exercised in meshing tho marked teeth of the magnetic rotor gear CW ROTATION Fig. 23. Position of Drive Spring i n Coupling Shell Aaaembly of Breaker Mechanism Remount the condenser on tho hearing support. On t r p e FM-XV magnetos t h e c a m wick and holder as#amI!ly ie mounted on the wndbnsar m o d i n g screw, along with tho condenser. On a l l other magoeton except those with feed-thru condensers the cam wick and holder 'assembly i s supported hy the No, 8 contact aupport locking aerew. Remount the broakcr arm aupport brnoket by means of tho two support bracket Locking screws, l o c h a s h o r s , and flat waahors. Slidc t h € a r m onto tho fulcrum pin and replacc the Iulcrum pin snap ring. Place the lead wire terminal from the coil, the terxbinal from the condenser, the terminal from the ground switch, and the end of the breaker a r m spring onto the breaker a r m terminal screw, and faaten thie screw i n - . page 9 Instruction M3-1 - ., Service Instruclians , COUPLING SHELL 0 nu' / LOCKWASHER Fig. 24. Magnetic Rotor and Disassembled Impulee Coupling the bottom of the aUDDort - - bracket. Measure the breaker. paint clearance and adjust the clearance i f necessary. Refer to paragraph under Breaker Arm, Support Brack. . et and Points,' far details on adjusting breaker paint clearances. marks onyour particular engine. Then rotate the crankshaft until the timing m a r k s coincide, indicating that the No. 1 cylinder is i n advance-spark firing position. Be s u r e that the piston is on i t s compression stroke. Impulse Coupling T r i p Method Sealing Magneto Coat the contact surface of the end cap of t h e standard magnetos with Fairbanks Morse FMCOZ Gasketvarnish. P l a c e e new gasket i n t h e joint and fasten t h e end ca$ on the housing with the end cap screws. Push a new distributor shaft seal into the distributorsshaft receas i n the end cap of types FM-XI, FM-XFZ, FM-XR, FMXOR and FM-XV4B7 magnetos. Replace the dietributor rotor on the end of the distributor shaft, pushing i t into place a s far a s i t will go. Then replace the end cap cover using a new gasket. TIMING MAGNETO T O ENGINE Accurate timing of the magneto t o the engine produces an ignition spark in each cylinder a t the u a c t instant the fael mixture should be ignited for best engine performance. This .indtaht, wliich i s determined by the engine manufacturer, i s designated a a a given number of degrees of angular travel of the crankshaft before the pietan reaches inner dead center on the compression stroke. When starting the engine, it i s advisable to ret a r d the ignition spark until it occurs late enough in the cycle to avoid backfiring. Impulse couplings when used with magnetos automatically provide this spark retarding feature while the engine i s being started. Magneto: Remount the end cap cover an the end cap. Set the magneto for spark discharge to the No. 1 terminal. This may be accompl<shed by use of a stiff, short length of w i r e placed in t h e No. 1 socwet a%d beht' to within 1.18 in. of the magneto frame. Then turn the magnetic rotor from .the impulse coupling end in ita normal direction of rotation until a spark i s observed beween the w i r e and the housing. Hold the coupling in the position in which the t r i p occurred. Engine: Remove the spark plug, o r otherwiee determine top dead denter for the piston in the No. 1 cylinder. Then turn the engine over until this position i s reached. baing certain that the piston i s just at the end of i t s compression stroke. Coupling Magneto to Engine Without disturbing the setting of either magneto o r engine a s determined by the methods above, couple the engine in the following manner Flange Mounting Magnetos: Engage the d r i v e lugs of the impulse coupling with the driving slots of t h e engine drive member. A slight movement of t h e engine flywheel may be necessary t o secure accuratm alignment. Tighten capscrewe and nuts securely. The importance of correctly timing the magneto to the engine cannot be ovcrem~hasized, and the steps desciihed below ahould b s &llowed Larcfully. ~ i i h e the r advancd spark position method a r the impulse coupling t r i p metbed may be used. Whichever mithod i s used. the breaker painta must f i r s t b e accurately adjusted to secure proper timing of the ignition spark. Base Mountins Magnetos: If no change h a s been made i n the position of the member, it i s n e c e s s a r y only to engage the drive lugs of the impulee coupltog with the drive slots of the float disc. Be aure that t h e shaft asaembly i s properly aligned before securing the base mounting screws. Advance Spark Position Method Adjustable Drive Members . the magnevo f o r advance s p a r k position in .>.."..,Y ~agnet:: ;set the No. 1 cylinder. This i s done by turning the rotor from the coupling end in the direction oppositeto normal rotation until the distributor contact lines up exactly with the timing boss. With certain exceptions the No. 1 outlet on four-cylinder magnetos i s the upper left of the four terminals. On type FM-XOR six-cylinder magnetos the Nq. 1 cylinder outlet i s usually diagonally upward, 30° to the left of vertical. When the magneto is timed for advance spark in the No. 1 cylinder, i t should be held exactly in the position until =&pled to the engine. Engine: Engine builders usually indicate by m a r k s on the flywheel and flywhcel housing, the position of t h e engine for advance spark timing. Refer t o the engine manufact u r e r ' s instruction book for details concerning timing Mast engines uslng base mounting magnetos a r e equipped with adjustable drive members, Fig. 25. Ordinarily the position of the drive member i s not altered when r e ULSE COUPLING L M Fig. 25. Adjustable Drive Member moving the magneto bukwhnn noceasary, the drive mllar nut L can be loosened to permit relative movembnt of the engine drive shnlt i n collar K The drive member slots J can then h a turnad for alignmentwith the impulse coupling luge, after which thc nut L should bc tiglrtoncd. The locking lugs M of the washer should be turned up around the nut to prevent it$ corning loose. On the self-mountcd ground w i t c h , a wire is rue from the p d m a r y terminal of ihc cail to a spring switet, mounted on t h e magneto huunirlg an4 is no arranged thnt when oparatnd the p n m n r y circuil i r grounded. On rho mounted switch the same prillmry coil wlre i s extendcd lo the control panel, usunlly through an mtermodiate terminal mountad on the magneto. Primary Ground Switches When stopping the engine by grounding out the primary circuit, thc switch must be kept closed until the engine atops. Englhea may be &topped by shutting off the fuel supply or grounding out the nagnoto ignition circuit. Shutting off ihe fuel supply has tho Qisadvantage of not stopping the engine quickly, while grounding the ignition circuit stops tho engine at once. Battery ignition systems must be opened to stop the engine while in magneto ignition systems the ignition circuit must be grqunded to stop the engine. Primaryground swtlihes must be located in the primary circuit of either typo magneto, Fig. 26. The action i. in8tnnbaneous and iuel is left in the fuel system for immediate starting. ~ h s r aare many typsa o r stylea of ground switches, but in general they may he divided into two groups, those located on the unit and those located away from t h e unit. Radio Shielded Magnotps The high voltage spark discharge, which provides ignition for the engine, often causes interference in radio reoention. Presuentlv it i e nacessarv or desirable to +liminatf thls intcrfetf;ence, Fig, 27, 'lo principle, the radio shielding of a magneto requires the r c p l a e m e n t of the plastic cnd cup by an aU metal end Cap wlth an insulated plnstic distributor bloc% mounted inside. SpeCial outlets are provided for t h e metal encased high tonston cables, and the spark plugs a r e metal covered. All this exterior metal housing ia intorconnected and grounded to function a s a shield and absorb the interference causing waves. On certain magnetos for military applications the primary ground terminal is located on the end of the feed-thru condenser o r on the end of the primary circuit cannectar. Fig. 26. Push-button and Lcver Type Type Ground Switchcs N g . 27. Complcte.Radio Shielded Magneto