1994 force 120 idle problem

fab9racing

Seaman Apprentice
Joined
Jun 16, 2008
Messages
42
I have a 94 force 120 i have just replaced all new pistons rings and bearings and the motor runs great its very quite, i also replaced all the electronics with new parts, trigger, and brain box with a rectifer as well, the problem i am finding now is when i let the motor idle for like 5 minutes it will juust get lower and lower till it kills, now if i pull the cowl off it will idle all day, it apperars to be starving for air, any ideas will be appreciated
 

chitownborn

Petty Officer 2nd Class
Joined
Jul 13, 2007
Messages
178
Re: 1994 force 120 idle problem

you might check your exhaust boot, it might be leaking
 

glenik

Recruit
Joined
Dec 4, 2008
Messages
4
Re: 1994 force 120 idle problem

My exhaust boot leaks like a sieve and I have this exact problem.
 

fab9racing

Seaman Apprentice
Joined
Jun 16, 2008
Messages
42
Re: 1994 force 120 idle problem

are you refering to the rubber tube that comes off the inner housing that just rests against that trim piece that has the 2 holes in it ? or the tube that connects at the powerhead that is about 3in square tubing ?
 

chitownborn

Petty Officer 2nd Class
Joined
Jul 13, 2007
Messages
178
Re: 1994 force 120 idle problem

its on the leg below the power head, its round and rests against the plate with two holes in it. if its leaking or not seated right it'll put exhaust fumes under the cowling and starve the engine of air causing the engine to quit, with the cowling off the carbs are getting clean air to run
 

fab9racing

Seaman Apprentice
Joined
Jun 16, 2008
Messages
42
Re: 1994 force 120 idle problem

yes i know what you are talking about man that is a lame design, i think ill drill that section out of that trim panel and make a section that will clamp to that exaust boot i seen that thing smoking somewhat but man they have so much bubbles coming up around that lower part of the trim bubbles all bust right under that little trim piece, i would have thought with all the engineers that chrysler or force would have fixed that problem.
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: 1994 force 120 idle problem

UH! Not quite as simple as it seems! That boot has a plastic bushing inside the tapered end that the internal spring bears against. SO: If you drill out the lower shroud, you will be increasing the size of the outlet.

That rubber boot and the vents in the shroud are the idle relief system. This relieves back pressure when the engine is sitting low in the water. Both exhaust and water exit here. If you enlarge the hole to clamp a fitting inside the boot, you are very likely to get more exhaust and stinky smoke at Idle.

Mind you: I am not saying you can not do it, just that you need to think about it before you do.

It is also my opinion that unless the boot is torn or broken, there really isn't much of a problem. The boot popping out of the seat doesn't happen too often. If your boot tears, it won't matter if you have it clamped or if it is sitting in the seat, spring loaded: It's still going to leak.

I just think you would be going to some unnecessary work and trouble. All you need to do is re-seat the taper and it may never pop out again.
 
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