225 Johnson Compression.

[Captn Dave]

The compression on my 1989 225 is approximately 80 psi in all cylinders. Otherwise the engine starts fairly well, idles okay and runs with no apparent loss of power. I suspect the rings are coking up and have tried Yamaha Ring Free but with no success. <br />Should I be thinking rebuilt powerhead at this time?

 

[nickster]

Re: 225 Johnson Compression.

Wave1<br /> I don't exactly know what the compression should be on that motor but it is tremendously low. There should not be no more than 15psi from one cylinder to the other cylinders. From what you have explained that they are all even but very low. So if it was me I would have the powerhead rebuilt.<br /><br />GOOD LUCK!<br />Nick

 

[Terry H]

Re: 225 Johnson Compression.

Wave...first thing I would do is to take a compression test using another compression guage...all guages are not equal...Thought101

 

[SeaDawg]

Re: 225 Johnson Compression.

Did you check the compression with the throttle wide open? I believe that is the correct way to check it.

 

[Fouled Plug]

Re: 225 Johnson Compression.

Rebuild? Depends on how many hours you have on the engine. It would be cheap and easy enought to try a spray-in decarb like SeaFoam or Merc's Power Tune and see if the #'s improve. If not, a squirt of oil into the cylinders and another compression test will reveal bad rings if the compression jumps up.

 

[dick]

Re: 225 Johnson Compression.

OMC ( BOMBARDIER ) looper engines have low compression 80-110 PSI is common. I would as sugested try another comp. gauge and if there all within 15% go boating.

 

[petryshyn]

Re: 225 Johnson Compression.

I'm with d!ck. If it starts, idles and goes, you're ahead of most. If it ain't acting up...don't fix it<br /><br />

 

[Captn Dave]

Re: 225 Johnson Compression.

Thanks for your help guys.

 

[trevorcday]

Re: 225 Johnson Compression.

Two strokes are funny about compression. If the cylinders were dry and/or the throttles closed when the test was performed that could easily account for the numbers.<br /><br />Do you still pull the same max. RPM as when the motor was new? If so the motor is still making the same power plus or minus.<br /><br />Don't worry be happy.