'79 Evinrude 35hp - No spark in bottom cylinder

[Captain Caveman]

Only the top cylinder is running. I know this because I replaced both plugs and the bottom one is still spotless after running the motor. Also, if you remove the plug boot while the motor is running there is no change.

I bought and installed a new ignition coil, but that didn't solve the problem. What could be the issue? I've read in a few threads that it could be the power pack. That may be true but I don't want to waste another $50 just to find out that it was something else.

How can I determine the source of the problem? Is replacing the powerpack the next logical step?

Thanks in advance.

 

[fireman57]

Re: '79 Evinrude 35hp - No spark in bottom cylinder

It could be if you don't have points in this engine. Try this first. Remove both the coils and swap them and see if the problem stays the same. If it doens't then it is the coil..Whe you got the new coil I'm sure it was one that you have to put together yourself. It is sometimes extremely difficult to make sure that the center of the wire is firmly on the post and that you got the spark plug coil wire in the center of the plug wire. The post in the coil is threaded a little and you almost have to screw it in. Measure the inside depth of the coil where the post is and mark your plug wire that goes into it so you know when you have it all the way in.

 

[R.Johnson]

Re: '79 Evinrude 35hp - No spark in bottom cylinder

There are no point's in this engine. Since you have fire on one cylinder, we may be able to narrow this down to, two component's. You replaced the coil, and the charge coil is good, or you would have lost spark on both cylinder's. That leaves the pak, and sensor coil. Remove the plug-in connector between pak, and mag. plate. Put a ohm meter between the black -white, white-black wire. It should read 40 + - 10 ohm's. Check each of these wire's to ground, meter should read infinity. If this check's good, that leave's the pak.

 

[R.Johnson]

Re: '79 Evinrude 35hp - No spark in bottom cylinder

For those who read this post early in the day, I was wrong about the wire color. The above is correct. These would be the wire's coming from the mag. plate sensor.

 

[Captain Caveman]

Re: '79 Evinrude 35hp - No spark in bottom cylinder

The coil did require assembly. Just to be sure that I didn't hose up the new plug wire, I lifted a spark plug wire off of my old truck and connected it between my new coil and the spark plug. It still did not fire.

When I get home tonight, I'll read the ohms to to see if it's the pak or not.

 

[R.Johnson]

Re: '79 Evinrude 35hp - No spark in bottom cylinder

That is probably a carbon core wire from the truck. Don't try to use that.

 

[fireman57]

Re: '79 Evinrude 35hp - No spark in bottom cylinder

What R.Johnson said. Have you tried swapping them yet? It only takes about 10 minutes.

 

[Captain Caveman]

Re: '79 Evinrude 35hp - No spark in bottom cylinder

Yes, I did try swapping the coils and the same bottom cylinder didn't work. I ordered a new power pack from iboats and hope that it will arrive either today or tomorrow. I'm crossing my fingers that it works.