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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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My 120hp force will start and run in the driveway with

Customer Question

My 120hp force will start and run in the driveway with earmuffs but will not accelerate in open water
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.

Hello. My name is Tan.

The first thing we need to do is a spark and compression test. The compression must be 90+ psi with no more than 10% difference between cylinders. The spark must jump a 7/16" gap on a spark gap tester on all cylinders.

If these test good then we know we have a fuel related issue.

Run the engine then when trying to get on plane choke the engine. Does it run better?

If no change then squeeze the primer bulb real hard. Does engine run any better?

Post back with findings and questions.