1996 40hp Mercury Force having issues when hot

[lugoismad]

I bought a 1996 Pontoon with a 1996 Force 40hp engine.

When I first took it out, it ran like crap. I took it home and took the carb off of it it cleaned it thoroughly and replaced the spark plugs.
I also installed a tell-tale and put in a new water impeller.

I took it out again. It ran much better. However, once it got hot, it started running crappy again. It wouldn't idle and even at full throttle was missing hard and only pushing the boat a few miles an hour.
I verified the tell-tale was pushing out water and it wasn't super hot or anything. Just ordinary warm feeling, but not boiling.

I've ordered a new coil pack set for it. From what I've read, thats the most likely cause.

I've also bought a fuel pump rebuild kit, which from what I've read should help with it idling.

I have a fishing trip coming up in 3 weeks and I either have to have the boat running or I have to pay $80 a day to rent a fishing boat, because I've already paid for the cabin and slip rental and its too close to get a refund.

Is there anything else you would suggest I try? Thanks!

 

[GYPSY400]

Try the coil pack and if that doesn't work don't spend a lot of time on it. Force motors are not worth the effort.

Sent from my SM-G903W using Tapatalk

 

[DaleH]

Try the coil pack and if that doesn't work don't spend a lot of time on it. Force motors are not worth the effort.

Unfortunately I have to I agree! I once spent far too much $$ and time (hours I'll never get back) fooling around with a 10hp of that make. Had the worst intermittent problem ever ... in that one day it would run ... and the next day it would not. When it ran, it ran de bomb! But ...

Turned out to be the powerpack that was flakey, which are reknown throughout the industry for being marginal at best.

 

[lugoismad]

Well I agree Force aren't the best, this one does have the Merc lower unit and electronics, so its not that bad.

 

[wmk0002]

My experience with a 1994 Force 70hp was that about every electric ignition component was junk. Ended up replacing almost all of them because they were all out of spec and I couldn't nail down the issue. That adds up real fast when those parts are $200 each. However, mine always idled fine. I would 100% get a manual and test the ignition components per those instructions before replacing parts. If you are lucky you can narrow it down and get it fixed.

 

[lugoismad]

My experience with a 1994 Force 70hp was that about every electric ignition component was junk. Ended up replacing almost all of them because they were all out of spec and I couldn't nail down the issue. That adds up real fast when those parts are $200 each. However, mine always idled fine. I would 100% get a manual and test the ignition components per those instructions before replacing parts. If you are lucky you can narrow it down and get it fixed.

The coils test good, but so does everything else. The motor starts acting up when hot.

Idles fine with cold, won't idle when hot. Which again, makes me think coils are going bad as they get hot.

I had ordered replacement coils, but they came today and its the wrong danged part.

So i bit the bullet and ordered a new set of CDM coils. Those coils are for a mercury, this engine does have the merc ignition components.

 

[wmk0002]

My experience with a 1994 Force 70hp was that about every electric ignition component was junk. Ended up replacing almost all of them because they were all out of spec and I couldn't nail down the issue. That adds up real fast when those parts are $200 each. However, mine always idled fine. I would 100% get a manual and test the ignition components per those instructions before replacing parts. If you are lucky you can narrow it down and get it fixed.

The coils test good, but so does everything else. The motor starts acting up when hot.

Idles fine with cold, won't idle when hot. Which again, makes me think coils are going bad as they get hot.

I had ordered replacement coils, but they came today and its the wrong danged part.

So i bit the bullet and ordered a new set of CDM coils. Those coils are for a mercury, this engine does have the merc ignition components.

My components were in spec cold but not if I checked them after they got hot. The switchbox was the worst if I remember right. It would cause one cylinder to miss badly at high speed and almost totally quit at idle.