Johnson 175 Low Compression

Hi there,

I have a Johnson 175HP V6 Loop charged on a Bayliner Trophy. The engine is about 1995.

I had a compression test done recently as last season I had some difficulty restarting the engine after a long run. It also was cutting out just as I put it into neutral/reverse approaching my mooring - still after a long run.

The compression showed all 6 cylinders at 70% when cold. I believe a further drop in compression when hot would explain why it spins over for so long without starting.

But the thing is, this doesnít always happen. I use the boat for sea fishing and I like to shut the motor off while drifting, but I'd rather leave the engine ticking over instead of running the risk of no restart.

Also, after a while itís inclined to steam from the tell-tale holes instead of water jets.

Am I looking at getting a new powerhead/ rings/ re-bore?

Is anyone familiar with this problem?



It sounds like it was overheated in the past and it is trying to live with cylinder damage. Have it rebuilt and you will be pleased with the result.




Please submit whatever questions you have to  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Mark C.


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