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Ask Dominick Your Own Question
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 1987 inboard boat with a 454 big block engine with

Customer Question

I have a 1987 inboard boat with a 454 big block engine with Indmar marine components. The engine starts fine and in neutral it runs fine. The engine will rev at high rpm in neutral with no problem. It also will run in gear at idle speed. But, when it is under load above idle speed it stalls. I have replaced the mechanical fuel pump, fuel filter, in-tank fuel pickup and I sent off the Holley carb to be rebuilt. When the engine is cold it will run under load for a few minutes until it warms up. Water is being circulated through the engine and out the exhaust so the cooling system appears to be working properly. I replace the impeller every 5 years. I doubt the problem is vapor lock because the engine is not over heating. If the problem is vapor lock why will the engine perform fine when not under load? Please help me identify a trouble shooting list. Are there any other things I can do before I hire a mechanic to attach a fuel pressure gauge and check cylinder compression?
Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.

Hi John, my name is Jason.

The engine needs 3 basic sets of checks done.

1. Compression test

2. Timing check, and check for timing advance

3. Fuel pressure test.

Are you able to do any of those checks on your own?

Customer: replied 1 year ago.
I have a timing light but it may be time to call a local mechanic.
Expert:  Jason replied 1 year ago.

Okay did you have any questions for me or did you want to call it quits?

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