1976 35hp Johnson compression

[jbond1717]

This weekend my 976 35hp Johnson decided to shut down a mile from the ramp. It sounded like it was running out of fuel, sputtered and died. I got it to turn over a few times but it just didn't want to start, trolled in. Tested the cylinder compression and got 85 on top and only 30 on bottom. I assume that I've lost my rings or a valve is seized but don't have a clue how much this may end up costing if in fact I need a rebuild.<br /><br />Haven't put a set of rings in anything since my 1975 Hodaka. Is this a do-it-yourself?<br /> <br />John in Mississippi

 

[G DANE]

Re: 1976 35hp Johnson compression

Hi Bond<br /><br />I had a couple of these motors. Compression normal reads between 120-135, when in good shape. It sounds like you probably overheated. I would first try to decarb if you can get it running at all. If not, try to pull the cylinderhead and take a look at the cylinderwalls. How does the plugs look like ? Light brown like coffe with cream is best. If clean = blown headgasket. If white = lean condition. Can you give us some more info.

 

[G DANE]

Re: 1976 35hp Johnson compression

First of cource, be sure you didnt just run out of fuel, or got some fuel restriction. The low compression can be an older problem. Did it run good before this happened.

 

[alcan]

Re: 1976 35hp Johnson compression

Hi bond<br />I agree with Dane on this one. You can try soaking the cylenders with the decarb stuff over night. Just bring the piston up close to TDC before you pour in the solution. Soak one at a time. You could also remove the intake bypass covers off, this will allow you to see the rings and a little cylender wall. Also poke rings with a pointed instrument to see if they spring. The soaking thing is a long shot, but at this point you don't have much to loose. Installing new rings in your out board will be a little more challanging than your Hodka. But what elese would you do with your spare time, go fishing,play golf? Any way good luck, let us know how you make out.