'79 Evinrude 35hp - Lost cylinder again...help!

[Captain Caveman]

Back in July, my '79 Evinrude 35hp lost a cylinder. I replaced both coils and eventually fixed the problem by installing a new power pack. It ran great for several outings until this weekend. I was putting along slowly when one of the cylinders stopped working again. However, later that night (without me touching a thing) both cylinders were running at full power again!

Someone mentioned something to me about the kill switch being problematic. Does anyone know more about this?

Does anyone have a suggestion as to why this may be happening? I suppose that it could be two bad powerpacks but I suspect something may be causing them to fail and/or operate sporatically.

Also, whenever I lose a cylinder the motor is extremely difficult to shift into and out of gear. Is this normal?

 

[F_R]

Re: '79 Evinrude 35hp - Lost cylinder again...help!

You could have temporarily fouled a plug with a bit of carbon. Carbon blew out and plug started firing again. Check/clean/or replace the plugs if it happens again. Sounds like your motor has a shifter/throttle interlock that prevents you from shifting with a high throttle setting. You have to set the throttle higher to keep it running on one cylinder, thus locking out the shifter.

 

[Solittle]

Re: '79 Evinrude 35hp - Lost cylinder again...help!

Captain - YOu need to buy the OMC shop manual for your engine and do some troubleshooting. Guessing and throwing parts at an engine can get frustrating. I'll bet you have a loose or dirty connection somewhere.

 

[Captain Caveman]

Re: '79 Evinrude 35hp - Lost cylinder again...help!

Captain - YOu need to buy the OMC shop manual for your engine and do some troubleshooting.

Good call. I have a shop manual for everything else in the world, I should get one here too.

Talking with a buddy last night over a few beers, he echoed the same thoughts about a loose and/or dirty connection. Specifically he mentioned that a dirty or loose ground wire could cause there to not be enough spark to get the cylinder going.

I'll order the manual and do some poking around. Thanks.

 

[Dhadley]

Re: '79 Evinrude 35hp - Lost cylinder again...help!

What spark plugs are you using?

 

[F_R]

Re: '79 Evinrude 35hp - Lost cylinder again...help!

I'm a believer in checking the most obvious and/or most likely stuff before going poking around looking for something wierd or exotic.

 

[Captain Caveman]

Re: '79 Evinrude 35hp - Lost cylinder again...help!

I still haven't figured out the problem (or found a short) but will keep looking. However, the tag on the spark plug wire says to use a L7V plug. The actual plugs that I have in there are QL7V JC4 plugs.

Any thoughts on what else could be the problem?