reed valve

[crappie lover ken]

my 87 115 hp yamaha shows i'm getting 0 compression on the number 2 and 4 cylinders. how ever when plugged it is harder to turn over than when not. meaning that compression is there. my question is could a bad reed valve be sending the pressure elsewhere in the crankcase giving me a false reading? or could there be some other problem?

 

[rodbolt]

Re: reed valve

sounds like a blown head gasket.
odds of breaking both reed boxs are slim and even with no reeds you will have compression.
maybenot the normal but you still will have most of it.
the reeds simply create the crankcase vacum and pressure required to move fuel.

 

[crappie lover ken]

Re: reed valve

thanks for the reply i will pull it today and check the condition. hopfully that is the only problem.