1994 Force 120 Compression good??

[Kevin9189]

I checked compression with all plugs out and hot battery. #1-94psi, #2-92psi, #3-95psi, #4-100psi. I know this is not the greatest compression, but will this engine still run in the water with these results??? It doesn't want to run in the water and of coarse it runs on the hose. It starts and runs in the water for about 30-60 seconds and then dies and gets harder to start the more I try.

 

[jerryjerry05]

Re: 1994 Force 120 Compression good??

Your comp is low.
It could be the gauge?
Or the procedures used.
You remove all 4 plugs?
Starting and running and then hard starting?
Could be the fuel pump diaphram?
Water in the gas?
Low/weak battery.

 

[Kevin9189]

Re: 1994 Force 120 Compression good??

I know it's low. Is it to low to run properly in the water or should it still run but not to full power?

 

[roscoe]

Re: 1994 Force 120 Compression good??

Yes, too low for that motor.

But why?

Very unusual to find all 4 low and nearly even.

Could be your gauge, your procedure, or ??

What do your plugs look like after running a while?

What is the idle speed on the hose?

What is idle speed in gear in the lake?

 

[JB]

Re: 1994 Force 120 Compression good??

Four cylinders don't go low the same amount at the same time.

Try this:http://forums.iboats.com/johnson-ev...ion-test-jb-313963.html?highlight=compression.

Your outboard has a different trouble related to fuel supply.

 

[Jiggz]

Re: 1994 Force 120 Compression good??

You are probably using a press down type compression tester vice the screw in type or it could just be a miscalibrated gauge. When you said dies in the water do you mean in neutral without doing anything it will just die on itself? If yes, then maybe you need to make sure the idle mixture screws for each carbs are at least one turn out from slightly seated and the idle rpm set to at least 1000~1100 in neutral in the water. If problem continues, try running with the cowl remove and if problem goes away check for exhaust leaks in the cowling area especially with the idle relief hose and exhaust plate gaskets.