Mercruiser 3.0 Bogging down after running good.

[Bfoster22]

Bought a 1986 4 whinn with mercruiser 3.0 . Just replaced plugs,wires,coil,points,cap,rotor,fuel filter. Got it running runs well for little while then bogs down. Will idle and uf stalls starts right back up but will bog down. Let it sit for a while then same.

 

[Scott06]

I assume you set the timing and dwell on the points ? What did the contents of the old fuel filter look like ? Next thoughts would be fuel supply/ contamination and cleaning and rebuilding the carb.

 

[Bfoster22]

Timing set, pulled old fuel out. Filter and flame arrester look fine. Changed filter in pump anyways.

 

[harleyman1975]

Could be a fuel pump going or a restriction in the fuel line. the crap in gas these days destroys the old rubber lines and may allow them to collapse on the suction side of the pump. try replacing that section first...even if it looks good on the outside. could be something inside the tank (like a plastic bag) clogging the pick up.

 

[Bfoster22]

Update. Ran gas can gravity fed into carb. She ran perfect. Now i know its a fuel issue but not carb.

 

[bentle]

Sound like the fuel tank isn't venting properly creating a vacuum lock. Check that you fuel vent line is clear, fuel pick up tube is connected and not cracked or plugged. Some have a pre filter on the pickup tube in the tank so make sure it's clear. If you can open up the fuel cap just a bit and carefully and motor runs normal then problem is most likely a vent issue.

 

[Bfoster22]

Thank you i will try all of that.