compression 50 psi all cylinders, 88 v4, 140 hp

denebach · Jan 10, 2013

The motor has been sitting on boat for 2 years without running. The owner said it ran fine at high speeds 2 years ago. What has happened and what can be done to get the compression us to 125 psi.

boobie · Jan 10, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

Did you try to start it ?? You may want to get a different compression gauge and try that for a second opinion.

samo_ott · Jan 10, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

And try some decard or seafoam in the cylinders. But I agree with boobie, try another gauge first. Rare they'd all be that low and consistant.

RogersJetboat454 · Jan 10, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

Agree with the others.
Borrow a compression gauge from Autozone (free after paying a refundable deposit), rinse and repeat...

nwcove · Jan 10, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

^^^+4. either the guage is flawed, or your method is flawed, or a combination of both.

bird33 · Jan 10, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

I just checked my compression with similar results. I then went back to Autozone to exchange the original tool and found out that the original was broke. After re-checking the PSI readings were almost double in my case. Cant beat renting the tool for a deposit and returning for same deposit.

denebach · Jan 11, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

I just checked the compression with an Auto Zone tester and found the same results. 50 to 55 psi for all 4 cylinders. Again, the motot has been sitting for 2 years without being turned over. The previous owner said it ran fine with power on the boat
More suggestions are welcome.

boobie · Jan 11, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

Again, did you try to start it ??

denebach · Jan 12, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

boobie said:
Again, did you try to start it ??

No, that is another problem. no spark. I will work on that today. Fortunately I also have a Johnson 120 that runs.

Chris1956 · Jan 12, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

You did crank it until the compression stopped climbing, right? You normally need 4-5 revolutions to reach max compression.

FARSCAPE23 · Jan 16, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

I have the same exact engine. 1988 looper V4 140hp, the one is on my avatar. When I first got it 3 years ago, boat was parked for 2 years, compression was under 60 psi on two cyl (starboard side). I ran the engine with one can of seafoam mixed with one gallon of gas, spray some seafoam deep creep thru the spark plug holes with the engine hot and problem was solved. Recheck compression and readings was 120 psi on all four cyl. Now I do this every 3-4 months and my engine runs perfect.

denebach · Jan 17, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

FARSCAPE23 said:
I have the same exact engine. 1988 looper V4 140hp, the one is on my avatar. When I first got it 3 years ago, boat was parked for 2 years, compression was under 60 psi on two cyl (starboard side). I ran the engine with one can of seafoam mixed with one gallon of gas, spray some seafoam deep creep thru the spark plug holes with the engine hot and problem was solved. Recheck compression and readings was 120 psi on all four cyl. Now I do this every 3-4 months and my engine runs perfect.

Thanks. I have read about using Seafoom in that way and will try it as soon as I resove the no spark problem. I have another CD power pack to try now. TBD

FARSCAPE23 · Jan 18, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

denebach said:
Thanks. I have read about using Seafoom in that way and will try it as soon as I resove the no spark problem. I have another CD power pack to try now. TBD

Keep us posted... Good luck ...

boobie · Jan 18, 2013

Re: compression 50 psi all cylinders, 88 v4, 140 hp

Have you tried disconnecting the black/yellow wire from the pack and see what happens with your spark prob.

compression 50 psi all cylinders, 88 v4, 140 hp

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