Very Low Compression on 25 hp Johnson

[flybyboat]

I bought a new boat that has a 25 hp Johnsin motor. it ran slowly and took awhile to start. After having it for about 90 days it did not get better. I was told that it might be the compression so i checked it and i could only get 10 psi out of the two the pistons. i made sure that i tested it correctly and even had a some one else check it with the same results. i dont know what to do, the book says that it should be at least 100 psi, i would be very happy to hear anyone ideas

 

[DJ]

Re: Very Low Compression on 25 hp Johnson

flyby,<br /><br />Several possibilities here.<br /><br />1. The cylinders are completely destroyed.<br /><br />2. The head gasket is gone.<br /><br />3. The rings are stuck.<br /><br />Try to remedy #3 first. Buy some decarbonizing agent from a boat dealer. Follow the instructions and see if it helps.

 

[Yepblaze]

Re: Very Low Compression on 25 hp Johnson

Perhaps you should get a second opinion from a different guage.<br /><br />Don't most "new boats" come with a warranty?