1981 Mercury 4.5 HP fuel flow problem

starcraft12 · Jul 31, 2014

I recently bought a 1970 Starcraft 12' along with a 1981 Mercury 4.5 HP outboard motor. The boat sat for at least a year. When I took it out for the 1st time, the engine would die unless I'd remember to pump the primer bulb every few minutes. Any clues as to the problem?

heron2000 · Jul 31, 2014

fuel pump

then rebuild the carb

I would do both

fuel pump1st

SumDumGuy · Jul 31, 2014

you should also consider replacing the impeller.

malaki · Aug 3, 2014

Replace the needle valve while your at it. Mine gave me fits and its $5.

JMichael · Aug 4, 2014

I had an older 3.9 Merc that did the same thing. Problem turned out to be a worn o-ring inside the fuel line connector where it connects to the engine. It was allowing a little air into the fuel line as the fuel pump tried to suck the fuel from the tank. There are a lot of possible reasons that can cause the same symptoms as others have listed some of them so you may end up chasing this one for a while before you find it.

starcraft12 · Aug 5, 2014

Thanks for all the replies. I'll start with the cheapest fixes first & work my way up.

1981 Mercury 4.5 HP fuel flow problem

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1981 Mercury 4.5 HP fuel flow problem

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