1984 Evinrude 70 hp compression

steamin53

Petty Officer 3rd Class
Joined
Jan 19, 2004
Messages
93
I just purchased a used 84 Evinrude 70 hp E70TLCRD not running with no spark. I'm sure I can get my money out of it if I don't fix the ignition problem by parting out the lower unit and power trim alone. BUT, I'm thinking about maby keeping it.

Here's the question. The engine sat in a shed for many years. I did a cold, dry cylinder compression test finding the following compression readings on the three cylinders: 114 top, 150 middle, 152 bottom.

Should I be concerned about the variance being greater than the recommended 10 to 15 psi difference between cylinders?

Could the variance between the top and the other two cylinders be caused by the engine having been stored so long?

As I recall compression readings in the 150 psi range are out of the ordinary for these 3 cylinder 70 hp models.

Help!

Steve
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 1984 Evinrude 70 hp compression

I'd be concerned about the top cyl. It could be the rings are just stuck or blown head gasket. Mix up some ATF and Acetone 50/50, dump it in and let it sit for a few days, turn it over every so often. Then recheck the compression.
 

steamin53

Petty Officer 3rd Class
Joined
Jan 19, 2004
Messages
93
Re: 1984 Evinrude 70 hp compression

Thanks for the reply boobie. How about some seafoam into the cylinder. Think that might loosen stuck rings if that's the problem?
 
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