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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16097
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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My mercruiser 120 2.5 liter 153 cubic inch engine keeps

Customer Question

Hi, My mercruiser 120 2.5 liter 153 cubic inch engine keeps blowing the exhaust part of the head gasket. Any idea what might be causing this? Rich
Submitted: 2 years ago.
Category: Boat
Expert:  Jason replied 2 years ago.

Hi Rich, my name is Jason

There are a couple of things that would do that.

1. Lean fuel condition - This can mean low fuel pressure or a clogged carb

2. Timing to far advanced

3. Incorrect spark plugs

4. Engine overheating in general

Starting with the timing and the plugs. Which plugs are in the engine? Do you know what the timing is set to?