1995 120 force no / low compression

[mmoorewa]

I have a 95 120 force. I bought it new in 95. I have gotten a lot of use but a few years ago had the idle adjusted at the dealer and it has been down hill ever since. I am a novice and am having a friend help who knows a lot about engines but little about outboards. I have lost compression in 3 and 4 and 1 has 36 and 2 has 55. It starts right up with the throttle wide open but will die when I get close to neutral. It runs but wil only top out at 32 MPH. Looking to start the process of taking it apart, starting with replacing the head gasket. Looking to get it running good enough to sell it. Thanks

 

[further]

Re: 1995 120 force no / low compression

Try a diffrent compression tester. Those readings don't sound right for a motor that starts, runs and does 32 mph?? Do you have a tach? Is the idle set right?

 

[mmoorewa]

Re: 1995 120 force no / low compression

Thanks, I will try a new tester. I know I have had problems with the idle in the past. Not sure how to adjust or test it. I am also seeing water in the bottom cylinder like a few other posts I have read. I have ordered a manual and waiting for it. Hope to be able to work on this weekend.
Another post recomended changing the head gasket. It was changed 3 years ago. Do you ahve any other suggestions? I am a novice and have never worked on engines before. Tach meter?

 

[199675hpforce]

Re: 1995 120 force no / low compression

First run different plugs like autolite's hotter plug. Use only high end semi synthetic oil. Now my plugs gunking up is gone. Just found out my carb float needle was stuck not allowing fuel into the motor cleaned it up. I plan on running mercury quick clean in fuel to avoid this in future. My motor should run great now.

 

[further]

Re: 1995 120 force no / low compression

clean plug + water in cylinder = head gasket. Pull the head and also inspect the cylinder walls for scoring/piston damage.

Tachometer - measures rpm's. You may have one already, if not you should consider installing one or picking up a tiny tach
http://www.tinytach.com/tinytach/index.php

 

[mmoorewa]

Re: 1995 120 force no / low compression

Thanks for your help, I had been running autolight for 15 years. Same oil then I changed to a different brand and now I have this trouble. I will check into a tach, new gasket, new tester, better plugs and oil. I just need to keep this running and sell it at the end of the year. When I had the idel adjusted 3 years ago they said there was a small nick on one of the cylinders. Can this be fix? How much to have it redone?

 

[jerryjerry05]

Re: 1995 120 force no / low compression

If you have low comp on 2 adjoining cylinders a head gasket has probably blown.You in salt water?? Fill out the profile.Someone might be close enough to help.
Remove the head and check the gasket.They sell parts here(i.boats) or at boats.net
NAPA sells parts too and can get them overnight.
You don't need hotter plugs.The factory insalled the right ones.If there was a problem with the air mixture a hotter plug will only mess up things further.
The price to rebuild can be as low as $1500 or $3500 depends on if the mech is gonna screw you.The dealers want LOTS to re-do one of these.
I usually charge about $1400 depending on what's wrong.
Your problem can probably be fixed for $35(head gasket).J

 

[Surlaw]

Re: 1995 120 force no / low compression

It's a 4 cylinder. What was compression on other cylinders? Sounds like you have a rebuild coming and the idle won't fix that.

 

[Surlaw]

Re: 1995 120 force no / low compression

Opps, I should read other post before I comment. I hope JerryJerry is right. Sounds like good advice.