Engine Only Firing on One Clynder??? Help!

[clarky711]

Greetings, this is in reference to my 1959 Evinrunde Lark 35 HP. I was just using the boat for a good run yesterday and after a few miles of wide open she started to loose power and wouldn't accept anything over 1/3 throttle. I had to limp it back to the dock on one clynder - I hope that wouldn't hurt anything worse, but I didn't have a choice.

I pulled the plugs and found that the bottom cylnder doesn't seem to firing. I will check for spark this afternoon (I guess the best way to do this is to have the plug in the cap of the wire and hold it close to some grounded metal), but after that I'm at a loss where to start. I guess I could pull the flywheel to inspect the coils?

Any suggestions? Are there special tools needed to get the flywheel off to get to the coils. Thanks.

MC

 

[tashasdaddy]

Re: Engine Only Firing on One Clynder??? Help!

submerge the motor in a garbage can atleast 1/2 way up the leg. start the motor. now pull the plug wire of the plug. you will here an rpm change. it it dies, that cylinder is not firing. then inspect the coils. you need a harmonic balancer puller, 3 # 8 hardened bolts, either 1/4 20 or 5/16 20, to go into the flywheel, standard bolts will strip in the flywheel.

 

[Chinewalker]

Re: Engine Only Firing on One Clynder??? Help!

Could be several things. Start with the easy stuff. Was the point cam wick present and oiled last time the magneto was serviced? A dry point cam will wear the point rocker arm down and close up the point gap, causing exactly what you described. A fouled plug will do the same. A bad coil or condenser will usually be intermittent at first before failing completely, but don't rule them out. Pull the recoil off, then remove the little access cover on top of the flywheel. A quick look may show the problem to be obvious if the coils are cracked or the points are dirty or closed up...
- Scott