low compression on bottom cylinder yamaha 25hp 2 stroke 2 cylinder

by andrew macdonald
(Townsville Australia)

 yamaha 25hp

yamaha 25hp

was using the boat when the outboard made a funny noise and lost power, continued to run rough and almost had no power and stalled a few times till i made it to the boat ramp. once home did a compression test and found the bottom cylinder had 35psi compression and the top cylinder had roughly 130. the outboard at times has a slight sneeze when idleing or going very slow and has stalled which i assumed i had a crappy fuel line connectorbut once up to a slight speed it ran perfect. Just wondering if anyone has any experience with this at all and wondering where to start looking first pistons, reed valves etc. or if there is a common easy solution that wont involve me stripping the outboard?
Motor is a yamaha 25hp 99 model 2 stroke 2 cylinder
Any help is appreciated.

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