Looking for some advice

[Shrimphawg23]

I have a 1995 M90A 90 horsepower Tohatsu. It starts up pretty easily. Doesn’t like to idle very well. Shuts off frequently when going into gear. Will run low speed and somewhat at mid throttle. WOT it will run 15-20 seconds then stalls down. I have to go to neutral and rev it up to continue at low speed. It is on a 21’ Carolina Skiff and I use it to pull a 30’ trawl net for shrimp. I am beyond crazy with trying to find the problem. I have replaced all fuel lines, cleaned the fuel filter, and replaced the fuel pump. Also has new spark plugs gapped according to the sticker on the motor, .040. When I first got it a couple of months ago it would run 34 kts with me and my father in it. Now I can only go about 6.5 kts.

 

[racerone]

Post the compression test results.----Does spark jump a gap of 3/8" on all leads?----Water pump impeller replaced ?

 

[pvanv]

When was the last time the carbs were Properly cleaned?

 

[Shrimphawg23]

When was the last time the carbs were Properly cleaned?

I have only had it for a couple of months. Like I said it ran excellent the first few times I took it out after that is history

 

[Shrimphawg23]

Post the compression test results.----Does spark jump a gap of 3/8" on all leads?----Water pump impeller replaced ?

I haven’t checked compression and have only checked spark plugs with a tester connected to them. I will check them to see how far they jump

 

[Shrimphawg23]

Post the compression test results.----Does spark jump a gap of 3/8" on all leads?----Water pump impeller replaced ?

Spark jumps 3/8” on all leads. Compression is 120 on all cylinders.

 

[Shrimphawg23]

Post the compression test results.----Does spark jump a gap of 3/8" on all leads?----Water pump impeller replaced ?

120 on all cylinders, spark jumps 3/8” water pump impeller replaced two months ago.

 

[racerone]

Check flywheel key.----Check reed valves.----Look into carburetors with a strong flashlight and compare amount of fuel coming up main nozzle. Do this at full throttle out on the water.----Oil injection checked ?

 

[Shrimphawg23]

How do you check oil injection?

 

[racerone]

It would involve running with 50:1 premix and measuring oil pump out put over say 10 minutes at fast idle.------Manual would have an exact procedure.

 

[Shrimphawg23]

It would involve running with 50:1 premix and measuring oil pump out put over say 10 minutes at fast idle.------Manual would have an exact procedure.

Okay thank you. I just got a manual today.