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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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Its an 1999 25 hp runs and revs up in neutral but does not

Customer Question

its an 1999 25 hp Johnson runs and revs up in neutral but does not rev in gear
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: I took it to the dealer he determined it was not pressuring right from the plastic gas tank and he put a new cap on it helped a little but not cured
JA: Is there anything else the Marine Mechanic should be aware of?
Customer: no
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Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.

Hello. My name is Tan.

With the engine running try squeezing the primer bulb does it run better? If no change then choke it does the engine run better?

If neither of these help then we need to do a spark and compression test. The spark must jump a 7/16" gap on a spark gap tester on all cylinders. The compression must be 90+ psi on all cylinders with no more than 10% difference between cylinders.

Post back with questions and findings.

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