120hp L-drive problem!

[fishin1789]

I just bought a 21ft. '92 Maxum Cuddy Cabin with a 120hp L-drive engine. The boat runs great for about 15 minutes and then will only get to about 2800-3000 rpm and naturally will not get upon plane. It is NOT overheating and will run at full throttle again after letting it sit for about an hour. Then the same thing happens. It will idle fine and run up to 2500 rpm just fine. Any ideas on where to start looking for the problem?

 

[pnwboat]

Re: 120hp L-drive problem!

I would suspect either a fuel or ignition problem. Most likely an ignition problem. Sounds like a component in the ignition system is failing under a load after it gets warmed up. Could be stator, trigger, CD Module or coil. You need am Ohm meter to do some basic checks. Do you have one available?

 

[fishin1789]

Re: 120hp L-drive problem!

Yes, I have a meter. Where should I start? Spark? CD Modules? Stator? Any help is appreciated! I bought this thing for a song since the previous owner was taking it to a dealer and getting hit with BIG repair bills ($2500+)for some shade tree mechanic to take things apart (fuel pump, carbs, powerhead, ignition switch, etc.)and tell him nothing was wrong. I feel like it is electrical, just have no experience with a Force engine. Always had Evinrudes before. Thanks!

 

[pnwboat]

Re: 120hp L-drive problem!

Here is a link to a chart that shows voltage and resistance readings for the stator, trigger, coils etc. You can increase the size for easier viewing.

http://www.cdielectronics.com/LinkClick.aspx?fileticket=Jb6eaecTaO0%3d&tabid=55&mid=383&language=en-US

 

[fishin1789]

Re: 120hp L-drive problem!

Thanks for the chart, it should help a bunch! Anyone else have the same problem?

 

[roscoe]

Re: 120hp L-drive problem!

Run it and when it acts up, check for spark.
Since it still runs but with limited rpm, I would bet it is a coil.

So let it get hot, check for spark.
If one plug is not sparking, swap its coil with one of the other ones.
Then check it again.
You may have to run it awhile to get it hot again.

So it the lack of spark follows with the coil, it is the coil.

 

[fishin1789]

Re: 120hp L-drive problem!

Thanks, Roscoe! I'll be on the water this weekend and already have a replacement coil at the ready!