Evinrude 1979 115HP Starting Problems

[115999R]

Gone the 9 yards with this thing, it tries to start but never acheieves idle and dies, won't fire for the next 3-4 cranks then will fire and try to idle or may back fire, fuel seeps from front of carbs when choked. Whats been done - Reconditioned power head, great compression, new power packs, timer base, plugs, wires, coils, fuel pump, fuel lines, rebuilt carbs, rebuilt thermostat unit, new water pump/impeller. Great spark on all 4, Getting adequate fuel. By passed internal tank and lines with exteranl tank with fresh fuel 50:1 new line and bulb, bulb is firm. Tried to sync according to manual, should be close enough to at least start. Don't know where to go from here, Any help or ideas would be greatly appreciated.

 

[OBJ]

Re: Evinrude 1979 115HP Starting Problems

Hi sickandtired...sorry ta' hear about yer problems.<br /><br />When you first tried to start the engine, that's the initial start after rebuild, did it backfire? <br />If so, and it's still backfiring, check your power pack leads to the ignition coils. Blue stripe lead to top coil, green stripe lead to bottom.<br />A hard backfire can blow the head gasket/s and cause water to enter the cylinder and give you idle problems. Hard backfires can also damage reed cages. This would cause the fuel to seep from the carbs.<br />Did you follow service manual instructions when rebuilding the carbs? Were they good and clean? Did you blow out idle and idle air passages with compressed air?<br />I'm going to assume you did a sync and link as outlined in the service manual. Throttle plates in sync with each other? One not going all the way closed?<br />Hope the problem is minor. Keep us posted.

 

[Joe Reeves]

Re: Evinrude 1979 115HP Starting Problems

SickAndTired..... With the spark plugs removed, and some kind of adjustable gap spark tester hooked up, the spark at cranking speed should jump a 7/16" gap on that engine with a strong blue flame.<br /><br />Spark plugs should be Champion QL77JC4 plugs with their gap set at .040. Compression should be in the 100+ psi range and even on all cylinders.<br /><br />The brass fixed jets within the carbs (high, slow, etc) should be cleaned manually. Do not rely on simply soaking them to be thoroughly clean.<br /><br />Be sure that the Orange/Blue wire from the packs to the coils goes to the top coils.<br /><br />Last but not least, and what I suspect may be your problem is that the flywheel key is sheared, or slightly sheared. With a key sheared completely, even if the flywheel was able to make a 180° turn, you would still have ignition but the coils would fire at the wrong time. Even a slightly sheared key would affect the timing.<br /><br />The sheared key scenario is caused by not torquing the flywheel nut properly. On that engine, it must absolutely be torqued to exactly 105 foot pounds..... any less = sheared key! If this happens to be the case, you'll need to clean up the damaged flywheel and crankshaft tapers to their original condition or suffer a repeat of the problem.

 

[115999R]

Re: Evinrude 1979 115HP Starting Problems

Thanks for your response OutboardJim. Back fire more pop than bang so should be OK. When motor replaced I also cleaned intake and reeds, they appeared to be fine, none stuck or broken. Pulled carb bowls and flushed passage ways with compressed air, check float leves, needle and seats, appear to be to speck. I replced the coils one at a time to insure wiring, as said, engine on occasion will roll over almost to smooth idle for an instant all four firing then quit.

 

[115999R]

Re: Evinrude 1979 115HP Starting Problems

Thanks for the response Joe, I think your probably on the money with the fly wheel, I reused the original key which was banged up a little and getting good tork without screwing up the fly wheel is a challange without the proper tool. I thought I was OK when checking the Key and slot alignment after cranking which appeared to be good, fly wheel has good seat but looks can be decieving. As said, Orifices cleaned manually but probably should check. Thanks again for all your help