Wisconsin Robin Wi-185

slomo

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Service manual pdf says 6.3:1 compression ratio. Wonder if my 60psi would equate to that? Sounds plausible.

Pdf file says cast iron bore. Thought it was.

Forged high carbon steel crank and forged rod. No wonder these were such sought after engines.

slomo
 

bertsmobile1

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Service manual pdf says 6.3:1 compression ratio. Wonder if my 60psi would equate to that? Sounds plausible.

Pdf file says cast iron bore. Thought it was.

slomo
6.3 x 14 = 88.2 PSI so it is a little low
 

tom3

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When you remove the oil dipstick the oil slinger will spray oil and air out the tube. (assuming a splash lube motor) Compression is probably ok. What oil are you using the engine?
 

upupandaway

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Anyone know if these Japanese engines have a cast iron bore?

Yes, it is iron sleeve.
Sounds like the bottom ring is not wiping the oil off the cyl wall or perhaps the drain holes from that ring are all clogged.
If I were u, i would remove the piston and clean the piston and replace the rings. I mean it is 30ish years old....
While you are at it, rent the cylinder bore gauge from Autozone or the like and measure it while it is open to see if the cyl is out of round.
Gasket wise, i used silicone gasket when i opened mine up, and you can always make a gasket for the cylinder head if yours falls apart.
 
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