125 Force idle/ low speed issues.

[Chevyboi001]

I posted a bit ago about having high idle, found few things wrong replaced a few things. Anyway recently i have this low speed, idle issue. The motor will choke down and cut off is idle or low speed for a period. Ive done quite of bit of searching and seems it could be a exhaust leak. either at the boot or the gaskets. i was gonna replace both but i cant seem to find the gaskets. when i look on the diagram of the leg i see a gasket at #24 but no listing or part number for it. If anybody has redon the seals on the exhaust because of this issue can you please let me know where or how to get the gaskets. i found the boot and clamps and springs for that. but did not want to teardown motor until i found all gaskets i would need to complete the job. I overheard somewhere that maybe even the gaskets are obsolete. What are people doing in this case? any help is appreciated. thanks

motor is a 1989 125 force us marine.

 

[pnwboat]

That part #24 exhaust tube seal is no longer available. If I remember correctly, I believe it's a thick foam type of seal. Maybe 1/4" thick or so. Some heat resistant neoprene foam would probably work just fine.

I would replace the boot, spring and clamp first. Very easy to do. Just have to take the lower leg rear cover off. See if that helps.

Replacing the exhaust tube seal means that you have to remove the power head. Much more involved and that exhaust tube seal is not something that goes bad very often.

 

[jerryjerry05]

It "could" be an exhaust leak?
​Or maybe it's getting hot at low speed?
Do a compression and spark test.

 

[Chevyboi001]

Comp last check when having carb issues, 140 straight across, spark plugs are new, coils ohm out correct. carbs are all rebuilt, fuel pump rebuilt. all connections are tight no wiring damage. boat wot runs about 38mph phone gps (20 ft maxum). water impeller new, prop new, gas good, everything is either replaced or rebuilt. have zero oil leaks, all i can think of is exhaust choking it out. im gonna try to get it in a tank this week and see if i can spot the leak. i will tell you my friend did say when i first start it up in the water he saw smoke coming from under engine cover blue smoke. that would seem to me as 2stroke gas.

 

[jerryjerry05]

Try running with the cover off??

 

[Derrick Fronckowiak]

Exactly like Jerry said. If you run it with the cover off and it does the same thing, then you've just eliminated the exhaust leak theory. If it runs better with the cover off then yep it could be getting choked by exhaust gas.

 

[Chevyboi001]

had it out on water removed the cover it ran fine. perfect never shut off once. also while in water with cover off tried to find source of leak cant see much but can assure everyone its not the boot.

 

[jerryjerry05]

The adaptor plate is usually the place it leaks.
​But if it only chokes out at low speed?
Then I'd guess the gasket in the lower part of the leg.

 

[Chevyboi001]

I removed the boot and found a plastic tube laying in there? my guess is it washed out of place but where does it go? thank for you help by the way.

 

[jerryjerry05]

It's called a stand tube.
​Should be 2 in there.
They are in 2 1/2in holes and stand upright in the holes.
Most times they are melted or broken.
Just plug the holes.

 

[Chevyboi001]

Haven't tore it apart yet, i found a good deal on a 150 force. until i swap it i just made a little fresh air intake system for the carbs, most would not agree with. With my life status right now(two jobs, 2 kids, wife,bills.) it works great. Motor will idle all day and never shut off. I plan on fixing but wanted to give I, kids a lil more water time before school starts so they are happy which means wife is happy which means ill live a lil longer in life. thanks for the help really!!!