Yamaha Non starter.

[Mercury]

Hi, I am having trouble with my Yamaha 4 hp 2 stroke. I have cleaned fuel line and carb, reed valve look good new gasket on reed valve & carb, and I have spark. Tried a compression test but it seems low to me around 80 psi. but not sure what it needs to be, does any one know ?

[beamishken]

80 psi does sound a bit low but its notoriously difficult to get an accurate compression test result on a pull start engine even if it is as low as 80psi I'd still expect it to start. If the plug is okay & you definitely have spark I'd try some neat petrol down the plug hole & see if it fires on that, just dont go too mad & that it cant turn over. If it fires you know its fuel related if not then you need to look elsewhere

[jeffstevens763@g]

120/150 psi normal