Compression

[Ponderosa]

I have a yamaha shop manual and have not been able to determine the normal compression.
I am refering to a 40etlk.
It has retired and I am trying to determine if it is worth fixing since it has a electrical problem that has yet to be identified.
I did a compression check and they seem quite low that would indicate a badly worn engine. readings 85 to 105 i did read that the compression is different on say cly 1 or cly 3.
where can i find the range?

[rodbolt17]

there are no factory numbers.
your posted numbers are out of the 10% range.
do a leakdown test.
if that fails its simply time to remove the head for inspection.

[200090tlry]

Decarb

Try a decarb and the numbers may improve. There are plenty of posts on this subject. Mercury,Johnson,Yamaha make cleaners. But Rod is king of Yamahas go with his opinion.

[rodbolt17]

decarb is quick and easy.
try posting the model number of the engine and why you checked compression.
thats seems to be the hard part on forums.

[Ponderosa]

ponderosa

I assumed that i posted the model number anyway the model # is 40etlk and I took the compression because i thought it was somewhat hard to turn over like a cly was (in my language ) dragging a bit which one was not known.

[rodbolt17]

its possible you scuffed a piston, leak down test wil show it as will a bore scope.
or simply remove the cylinder head,easier said than done on a saltater motor.