Compression on 1977 70 hp Johnson

catfish109tc

Recruit
Joined
Jan 21, 2002
Messages
1
Hello,<br /><br />I am just curious as to what the values in each of the three cylinders should be.<br /><br />Thanks
 

ob

Admiral
Joined
Aug 16, 2002
Messages
6,992
Re: Compression on 1977 70 hp Johnson

catfish109tc , A healthy outboard will produce numbers of 100+ and cylinders will be within 10% on readings.
 

cvlngineer

Petty Officer 2nd Class
Joined
Jan 22, 2002
Messages
137
Re: Compression on 1977 70 hp Johnson

I found a 1977 70 hp Johnson, and the compression is 135 135 137<br />Does that sound acceptable?<br /><br />cvlngineer <br /><br />(oops, I logged in with my old username-catfish109tc. I thought I had lost my password for this one.)
 

ob

Admiral
Joined
Aug 16, 2002
Messages
6,992
Re: Compression on 1977 70 hp Johnson

Those readings look very good.If you don't have record of the last lower unit service I would change the lube.Hopefully the rest is good to go.<br /> PS I like the redfish pic. :D
 
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