compression on 1987, 200 HP Johnson

[SancheAr]

Today I did a compression test on my 1987, 200 HP Johnson outboard and all six (6) cylinders are 75 PSI. What is a normal reading for this type of engine? Thank you, Armando

 

[rodbolt]

Re: compression on 1987, 200 HP Johnson

hello<br /> quite a bit of the late 80's early 90's v6 loopers ran about 80 psi. the first one I checked I went and got another gauge. I suspect your gauge may be somewhat off. all you are looking for is that highest to lowest is within 10 psi. there is no set spec for the actual PSI reading.<br /> good luck and keep posting

 

[james roach]

Re: compression on 1987, 200 HP Johnson

My 1987 200 Johnson runs around 100 psi. With 75 psi all around, as long as your motor runs good and starts good I wouldn't worry about it.

 

[SancheAr]

Re: compression on 1987, 200 HP Johnson

Before replacing the mid section, I wanted to make sure that the power head is worth the expense. The motor is running good except, the steering arm is completely rusted and needs replacing. Between parts and labor it will cost me $900 and the mechanic is recommending to replace the whole mid section due to the time it will cost me to remove and possibly break a few rusted bolts. My concern is that with the compression reading of 75 PSI, is it worth replacing the mid section or better to replace the whole motor? Thank you for your input, Armando

 

[Dhadley]

Re: compression on 1987, 200 HP Johnson

If its been a while since a decarb job, this may be a good time for one. <br /><br />Let us know how it turns out!