'89 Force 125 hp compression problem

[brenandryan]

Here is a little history on the boat, our friend gave it to us after it sat in his driveway for about 4 years. Last year we got it running great. We have taken it out twice this year, neither time could we get it over 15 mph. Both carbs have been rebuilt, it new has reeds, all gaskets have been replaced. Can't find any vacuum leaks. Spark plugs #2 & 4 are dry. Checked the compression tonight & #4 was about 25 psi lower than the other 3. First three are right around 125, #4 is at 100. When we cover the top carb, the engine dies out. When we cover the bottom carb, nothing happens. Other than rebuilding or buying new powerhead, does anybody have any suggestions?

 

[JB]

Re: '89 Force 125 hp compression problem

Bottom carb rebuild failed. Do it over.

 

[pnwboat]

Re: '89 Force 125 hp compression problem

Helps if you have the year, HP and serial# of the motor.

Sounds like you have a 125 or 120 HP 4 cylinder. First thing I would suggest is to get a manual if you don't already have one. Compression readings are OK, not the greatest but it should run OK. I wouldn't assume that you need a re-build at this time. Some basic trouble-shooting should get you pointed in the right direction.

1. Verify you have good strong snappy spark on all 4 cylinders.
2. Verify you are getting gas to the bottom carb. Remove the bowl and see if gas drains out. Bowl should be pretty much full of fuel. Needle valve may be stuck closed from debris. To eliminate this in the future, install an inexpensive inline filter between carbs and fuel pump.
3. Check filter screen on the fuel inlet cover to the fuel pump. Clean if needed. If you haven't replaced the fuel pump diaphragm, I would do so at this time.
4. Check ground connections on all 4 coils and ground from coil mounting plate to block.
5. Check primer bulb. It should get hard after squeezing 3 or 4 times.

 

[JDP]

Re: '89 Force 125 hp compression problem

Had the type of problem with my 86 125. Turned out to be the CDI pack for #3 and #4 went bad. I would as previously suggested and check for spark on all 4 cylinders.

 

[brenandryan]

Re: '89 Force 125 hp compression problem

We checked the fuel diaphram. There are cracks all around the big one and a hole in the small one (sorry, don't know the terms!) Could that be the culprit?

Thanks for everyone's assistance. We live in Phoenix & you would think we would have more people out here who could fix boats. We have taken it to 4 different people and nobody has been able to fix it.

 

[chitownborn]

Re: '89 Force 125 hp compression problem

yep, your diaphram is toast, easy to replace and not expensive