Still having problems....

[GreenF350]

If you look back on earlier post I had I have a 1991 40hp that had the powerhead replaced with a 48hp one. It runs pretty good at the higher RPM's, but the idle wasn't/isn't right. I have been having the suspicion that it was ignition not fuel and it looks like I was correct. Today I replaced the plug wires, checked for a leak at the carbs and just tinkered with it for quite some time. Here is what I found out....Hooked a tach to it that read off of the spark plugs....it's for 4 strokes, not 2 strokes....so that is why it is high, but here are the numbers, about 1800-1900 on the lower cylinder and (here is the kicker) about 2800-3000 on the top one. Since it is idling at about 1000 give or take depending on which tach I use (a mechanical on the flywheel or the boat tach) I assumed that the upper cylinder was double firing for some reason. I hooked up the timing light to the #1 plug and sure enough....it was firing every revolution just before TDC but running the timing light around the flywheel it is also firing, I guessing based on the position of the timing mark, just as the piston is starting to "come back up". That explains why I had to advance the timing so dang far to get it to idle....it brought it closer to the beginning of the piston going up having less affect on the way it is running. This is not good since it puts my boat down until I get this figured out, I don't see any signs of detonation on the plugs though, so hopefully nothing is damaged.

SO...any ideas on this one? I have already changed the ignition module...what else? The bottom cylinder is firing correct, so what is messing up the top? Now I am really confused.

-Aaron

 

[R.Johnson]

Re: Still having problems....

Mark the flywheel, and see if it truly is double firing. If so, replace the pak.

 

[GreenF350]

Re: Still having problems....

Mark the flywheel, and see if it truly is double firing. If so, replace the pak.

I don't understand what you mean by mark the flywheel. I have the timing marks, marked in white. With the timing light on #1 cylinder I can see the timing marks at TDC and just over 180 out. I can't see them anywhere else around the rotation, Unless I put it on #2 then it fires just before where the second firing of #2 is.

That being said, when I replaced the ignition module, I actually asked for the power pack for a e40eleia and it doesn't have a "power pack" they call it an ignition module and it's the "power pack" and "ignition module" together, or so I was told. I don't see the traditional power pack(s) like my buddies '78 150hp has. This thing has me baffled.
-Aaron

 

[tcan]

Re: Still having problems....

I'm not to familiar with marine 2strokes but I have worked on a few 2stroke bikes think it could be your pickup coils?

 

[GreenF350]

Re: Still having problems....

That is kind of what the ignition module is. It is what the magnets pass over that "triggers" the spark. That is actually what I think it is and I went to the dealer that I bought the ignition module from today. They said that the ignition module either had a 90 day or a 1 year warranty on it, then came the big whopper "Who installed the part?" That was me. I am no expert on boat motors, but I was a certified auto mechanic before I joined the military, I currently am a mechanic on airplanes, and I have been doing my own work on everything I own from lawnmowers, to dirtbikes, to boats since I can remember. Well, they decided I needed to talk to one of their mechanics to decide if they were going to warranty it. He kept asking "Did you do ____" Everything he asked but one I had done. That was set the timing at WOT. (I didn't want to hang off the back of the boat at 35mph to check it.) He said that it he had never seen nor heard of an engine double firing like that and it must be something else. Nevermind the service manual I have specifically mentions double firing caused by that part. I'm kind of frustrated right now, but I will go back out tonight if the storms hold out and give it a look over one more time and then I guess I will be out-of-pocket for another $160 ignition module.
-Aaron

 

[CATransplant]

Re: Still having problems....

If it's the factory manual you have, and the problem isn't solved, take the manual in with you and show the guy what it says. That should be enough to get the warranty honored.

There also may be a service bulletin on that model. If so, it will offer a remedy.

The biggest problem you may have is having the 48hp powerhead on the 40hp frame. That may cause them not to honor the warranty. I don't know.