125hp force runs rough at low speed and dies at idle

[B.B.Upch]

88 125hp force. Ran decent but wouldnt idle. I could get it to crank and quickly put it into gear and it would run pretty good but if I tried to take it back to idle it would start to run rough then die.. we spent 2 hours out on the water yesterday tubing and every time I would idle it down to pick up the girls it would die.. then take me 5 minutes to get it cranked up and running again? At wide open it ran good but low speed it was a little rough.. it smoked pretty good and seemed to be running a little rich..
also at wide open it ran good and got on top of the water but would only run about 45 to 50mph? Is that good? My dad had his 70hp fishing boat and i could barely keep up with it... so I felt like it should be running a little faster even at top end.
any help would be greatly appreciated thanks

 

[jerryjerry05]

First: compression and a spark check on each cylinder????
Post your results????
What rpm's is the idle set at? 800 in gear.

Check the gas for water.

Get a can of starting fluid, start motor and spray the SF around the intake side of the motor, at the carb base, then around the port covers under the coils/packs.
If spraying makes any difference , cough/ stutter/ stall?? then there's an air leak somewhere and the motors sucking air.

Pull the plugs and check for even burn, post pics?

If the SF test makes no difference. then try cleaning the carbs and check the reeds while they're off.
The first 5 posts in this forum: READ THEM there's a lot of good info there.
The "link and sync" might help?

 

[foodfisher]

Sounds like your fuel recirculation system is plugged. Hard starts and heavy smoke. Speed sounds too fast. Maybe your over propped overloading the engine. Usually hear about mid to upper 30's.

 

[B.B.Upch]

First: compression and a spark check on each cylinder????
Post your results????
What rpm's is the idle set at? 800 in gear.

Check the gas for water.

Get a can of starting fluid, start motor and spray the SF around the intake side of the motor, at the carb base, then around the port covers under the coils/packs.
If spraying makes any difference , cough/ stutter/ stall?? then there's an air leak somewhere and the motors sucking air.

Pull the plugs and check for even burn, post pics?

If the SF test makes no difference. then try cleaning the carbs and check the reeds while they're off.
The first 5 posts in this forum: READ THEM there's a lot of good info there.
The "link and sync" might help?

I did a compression and spark test before rebuild. 1st thing I did actually. Between 120 and 130 compression on all 4 cylinders and good spark. I cleaned fuel tank and put fresh fuel in it. I did a vaccum check by spraying carb cleaner all around it while it was running and no change.
I was wondering if it was the air valve adjustment? Or a carb adjustment that I might need to check.
Also from gauge doesnt work so not sure what rpms I'm running at idle.

 

[jerryjerry05]

They sell a small tach.$15 Called Tiny Tach.
What's the compression and spark now?
Comp can change in 1 trip around the lake.

Set the air screws at 1 1/2 turn and adjust from there.

Any gas coming from the front of the carbs? Check the reeds?

 

[B.B.Upch]

They sell a small tach.$15 Called Tiny Tach.
What's the compression and spark now?
Comp can change in 1 trip around the lake.

Set the air screws at 1 1/2 turn and adjust from there.

Any gas coming from the front of the carbs? Check the reeds?

Compression test still looks the same. Didnt write down exact numbers but all fell between 120 and 130. I'm going to replace the spark plugs since I have them out.
There is a little sputter out the front of the carbs... how do I check the reeds?

 

[B.B.Upch]

What spark plug should I run? I have champion l77cj4 now

 

[jerryjerry05]

Reeds: pull the carbs and check behind them.
There might be small gaps, no broken or missing.
UL 18V

 

[B.B.Upch]

Ok so we tried to adjust the air flow screws amd the timing/idle screw and we got it to idle ok but still running rough. And something new happened that we noticed. It would idle ok with the hood off but as soon as we put it on it would die? What would cause this? I think this might be my problem...

 

[jerryjerry05]

"And something new happened that we noticed. It would idle ok with the hood off but as soon as we put it on it would die? What would cause this? I think this might be my problem."
We call this a clue!!!!

If it dies with the hood off? then check the rubber boot where the exhaust exits the mid section.
That OK? then you have an exhaust leak somewhere?
Usually where the block meets the adaptor plate????

"Ok so we tried to adjust the air flow screws amd the timing/idle screw and we got it to idle ok but still running rough"
Do the starting fluid test:
Can of SF, start motor, spray the SF around the intake side, including the port covers and around the fuel pump.
If this makes a difference in the way it runs? Then it's sucking air sommewhere???
Possible: one little cough or backfire can blow the port cover gasket/gaskets.
If so? it will never idle right until the air leaks fixed..​

 

[B.B.Upch]

Thanks Jerry
We did the sf test yesterday when we had it in the water and nothing changed. I sprayer around the block, the fuel pump,the carbs, all over the motor and no difference. Just checked the exhaust and it's free and clear as far up as I can tell... (should be since it smokes like a demon lol). Pulled the carbs amd there are no reeds... nothing behind the carbs?? Not sure if that is normal.on an 1988 125 force or no but posting pictures... also tried to post videos but no luck.
stills seems to be running rich and smells of gas
I was wondering if putting the hood on was causing it to starve for air and that's why it would die when we put it on...

.....NVM... I just realized I have to take off the MANIFOLD on this one lol.....

Also the idle screw?? Or timing screw?? Not sure which is which but if I put just a slight pressure on it then it would run great but as soon as I let go it would run poorly again.. we adjusted it so that it was as far forward as we could get it.

 

[B.B.Upch]

"Also the idle screw?? Or timing screw?? Not sure which is which but if I put just a slight pressure on it then it would run great but as soon as I let go it would run poorly again.. we adjusted it so that it was as far forward as we could get it."

Here is a picture of what I am talking about

 

[The Force power]

You don't need to take the manifold off to see the valve-reeds, but it would help for a good inspection!
The top screw is to set/adjust the timing; do this first ! (with the proper tools)

The bottom screw is part of you link & sync. the carbs.
(follow instructions in the sticky notes at the top of this forum, if more info is needed; use the search-bar and type in keywords pertaining the problem/ this has been discussed & explained multiple time)

You could also check the re-circulation hoses/screen(s) for blockage (they're on the starter side) make a note of where what goes to put it back correctly

Keep us posted :ranger:

 

[jerryjerry05]

Both pics show the reeds???
Google Force outboard reeds?

The top screws for setting the timing.
The bottom is for setting the linkage.
Look up Link and Sync.
A video from FrankA shows how to do the initial setup and the static timing.

You read any??? of the posts in the front of the Force forum?
I mentioned it before.
They cover a lot of things that would have fixed your problems.
Read them.

 

[B.B.Upch]

Yes I watched both videos on it a couple of times and read through the threads. I'm going to get a buddy of mine to help me look at the timing when he gets back from the coast. I found the idle screw but Is the idle screw hard to turn? I found the idle screw but is really hard to turn even a little bit

 

[jerryjerry05]

The idle screw has a 1/4-20 nut at the base.
Undo that and the screw should turn easily.
WD for the hard turning?

 

[B.B.Upch]

Ok I watched the set & timing carbs a couple of times and read other posts... 1 thing I'm still not sure of is adjusting the cam. So with the motor off and in neutral. The cam is to far forward but when I move it back then open the throttle to "wot" then the carbs dont even open half way? Cant get this adjusted where it lines up amd still opens up in wot.

Here are pictures of what I'm talking about. The first set is with the - on cam plate even with carbs. But when u put it in "wot" the carbs barely open..
the last 3 is with - underneath the carb adjustment screw but when in "wot" the carbs open like the should.
am missing something?

 

[B.B.Upch]

Ok so I adjusted the idle screw since it was all the way in and tightned up the throttle cable so now when it's in neutral the cam plate lines up close with the black roller on the throttle rod of the carbs.. and when it's in "wot" the carbs actually open close to horizontal if not a little further. Now I'm going to check the timing and get it set. Then try and crank it and see what it does.

 

[The Force power]

Ok so I adjusted the idle screw since it was all the way in and tightned up the throttle cable so now when it's in neutral the cam plate lines up close with the black roller on the throttle rod of the carbs.. and when it's in "wot" the carbs actually open close to horizontal if not a little further. Now I'm going to check the timing and get it set. Then try and crank it and see what it does.

Remember to check/set the timing at WOT while cranking the engine with a tested / good battery

 

[B.B.Upch]

Remember to check/set the timing at WOT while cranking the engine with a tested / good battery

Yes Sir will do. Thanks. And it should be at 30° at "wot" at cranking?