[paul1]

i have a Mariner 40h outboard don't know the year 2stroke single carb.the problem i am having is i am losing power on top end and fuel is not pumping through properly have to pump it though with primer pulb on fuel line.it is ok on tick over.any advise would be gratefulpaul

[rickdb1boat]

Sounds like fuel restriction or fuel pump needs replacing. I would check all the fuel lines for air leaks, replace primer bulb and connectors at Fuel Tank and the Motor. If this does not do it, replace the Fuel Pump. Can you give us a Model and Serial Number? Would help in diagnosis!

[paul1]

the only number i can find is 67600 on the engine.it is a yamaha mariner 40hp 2 cylinder single carb.the age is somewhere between 1977-1989 i think.paul

[rickdb1boat]

I believe it is a 1987 Model.1987 - H

[paul1]

thanks for the advise will try that tompaul