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1980 Mercruiser 470 acts like it's not getting enough fuel.

MILLER88

New member
Just bought a 1980 Cobalt with a Mercruiser 470. Put her in the water, worked a little to get her started, then ran her for about 5 minutes. We stopped and let her sit in idle...she died. Had to work to get it started again. Tried to put it in gear and it died, which happened several times. Finally got it running again, ran it for another 5 minutes, then slowed to idle. She died again and would not go in gear (forward or reverse) without dying. Had to swim it to the trailor. Took it to the shop, the guys checked several things...checked the fuel filter and put a different pump on, among other things. She started up at the shop and seemed to be running better. Put it in the water about a week later and it ran fine for a few minutes, but once we got up to around 3800 - 4000 rpm, the rpm's started bouncing and the engine would cut out. We stopped for awhile and then ran it again. At first it did like before...died everytime we tried to put it in gear. Then we got it moving but it wouldn't go much above idle without either dying or sputtering real bad. Thinking it's probably a carburator problem...sound about right?

Also...at the risk of sounding stupid, my service manager is telling me that the engine is a chevy block with a ford head...I know ford was involved in the making of these engines but was chevy?
 
Block is Mercruiser`s custom alum block that used Ford parts.
Check the fuel tank vent line
The anti-syphon valve
Try disconnecting the main line at the fuel pump and plug a outboard tank in for testing.
 
"...but once we got up to around 3800 - 4000 rpm, the rpm's started bouncing and the engine would cut out."

Listen to the Bt Doctur's advice. Bouncing tachometer can mean it is failing. It will kill the ignition. Disconnect it at the coil if the problem persists.
 
What Bt Doctor and Bertg said. I've had problems with both. I removed both anti-siphon devices (the oem fuel filter at the carb inlet has a one way rubber flapper that can stick closed I just buy a fram w/o the flapper) and never had a fuel problem since.
 
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