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Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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I have a carburated Mercruiser 5.7l with Alphi I outdrive.

Customer Question

I have a carburated Mercruiser 5.7l with Alphi I outdrive. It was running well and I let it sit for about a month and a half in the marina. I took it ouut yesterday and it started easily, it ran nicely leaving the marina but as soon as i tried to get the rpm up towards 3000 it started to hesitated and backfire - if i pushed it further it would backfire and stall. It contoinued to run fine at low rpm. In neutral I could run it to 3500+ rpm and it was fine. so it was only problematic under load. Any idea what this could be?
Submitted: 4 months ago.
Category: Boat
Expert:  Jason replied 4 months ago.

Hi Mike, my name is Jason.

It could be a number of things. Do you, or can you say for certain, if it was backfiring through the carb, or out thrugh the exhaust?

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