No compression?

[vanceboroguy]

I have a 1978 Evinrude that has virtually no compression on one cylinder ,the other five have 125lbs.The cylinder with no compression will build up to 60lbs.What can I expect to find wrong? How long will motor hold together like this? I noticed the last three times we skied it was not as strong out of hole and idled not as well as it had. Motor is old but was never used much.Will cylinder receive enough oil this way or will it seize? The boat will still go around 39mph,but used to run in the 40s.

 

[JB]

Re: No compression?

It is broke, vbg. Do not run it again until it is fixed unless you are prepared to have it blow up 10 miles away from the ramp.

"Virtually no compression" and 60psi are not even close to the same. Please report only facts.

Pull the head and inspect. Let us know what you find.

 

[vanceboroguy]

Re: No compression?

True,when turning over motor to check compression ,a few revolutions,all cylinders at 125. One cylinder 0. I spun it over many times and gauge built up to 60. Give me a break,I am not a mechanic.

 

[kenmyfam]

Re: No compression?

I'm with JB on this one. Find your problem. Could have some ring damage in there or worse.

 

[Daviet]

Re: No compression?

I agree with JB, it will run till it either throws a rod or siezes. Might be a cheeper repair before major damage happens.

 

[emdsapmgr]

Re: No compression?

Pull the head off on the bad side. Possible it is just a bad head gasket-a relatively easy and inexpensive fix. When you remove the head to check, you will see what the cylinder looks like. If the cyl failed due to lack of lubrication, stuck rings, or ring failure, you should see it.