1988 force 125 won’t stay on in water

[Oillywater]

Hello I have a 1988 force 125 bay liner capri
My problem is that when I have the boat out the water and I start it. It starts right up and will stay in it will stall out occasionally but for the majority of it it runs good and stays on. Took it out to the water and it has difficulties starting and when it starts it idles but stalls the if u put it in gear you have to dump it in gear or it stalls.
Before I was on here since it wouldn’t start. I had a magneto problem but I just disconnected it on the motor and have been killing it with the choke. Then it was timed way off set the timing and it ran good. Now I just have this problem. I’ve cleaned every inch of the carbs multiple times only thing I notice is the bottom carb idle screw is very worn out. I’ve changed the fuel pump gaskets and port cover gaskets.
Please help me. And maybe I can use this information for my jetskies as they also are the same but they just won’t start in the water but out they instantly start

 

[Nordin]

The major different you have between running on muff and running in water is when in water you have the water back pressure.
First check to run in water without the engine top cover on.
Maybe you have an exhaust leak, check for leaks around the exhaust cover plate and the exhaust/water rubber boot at the back of the mid leg cover.
You say the bottom carb air/fuel mixture screw is worn out.
That can be an issue too, check by turning that screw in when idling.
It should affect the idle cause of a lean mixture, if no affect this is part of the problem.

 

[racerone]

Step #1 for a misbehaving motor is a compression test.-----Post the actual numbers here.

 

[jerryjerry05]

Compression test on BOTH, outboard and jet? Spark test?
What's the idle on the outboard? should be 750-800 in gear in the water.
Try running with the cover off(Nordin)
Try the starting fluid test. Start the motor, spray the SF all around the intake side of the motor. That includes the base of the carbs and the area under the packs and coils, around the 4 port covers. If that makes the motor run differently then it's sucking air in that area.

 

[Oillywater]

Step #1 for a misbehaving motor is a compression test.-----Post the actual numbers here.

Compression test on BOTH, outboard and jet? Spark test?
What's the idle on the outboard? should be 750-800 in gear in the water.
Try running with the cover off(Nordin)
Try the starting fluid test. Start the motor, spray the SF all around the intake side of the motor. That includes the base of the carbs and the area under the packs and coils, around the 4 port covers. If that makes the motor run differently then it's sucking air in that area.

Sorry forgot to put the compression test numbers. #1-150psi
#2-145psi
#3-145psi
#4- 145psi
As for the cover it’s about the same with it on or off
As for the jet ski I haven’t done compression test yet but once I got it started it ran really good she was purring. But I’ll do the test and post it.
As for idle when in water I’m not sure i don’t know if the rpm meter is right but if I can remember correctly it’s around 1-2k sometimes it’s below 1k

 

[Oillywater]

The major different you have between running on muff and running in water is when in water you have the water back pressure.
First check to run in water without the engine top cover on.
Maybe you have an exhaust leak, check for leaks around the exhaust cover plate and the exhaust/water rubber boot at the back of the mid leg cover.
You say the bottom carb air/fuel mixture screw is worn out.
That can be an issue too, check by turning that screw in when idling.
It should affect the idle cause of a lean mixture, if no affect this is part of the problem.