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Dominick
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 surging problem with my starboard 275hp verado

Customer Question

I have a surging problem with my starboard 275hp verado surging from 980rpms up to 1180rpms without touching the throttle, any ideas?
Submitted: 1 year ago.
Category: Boat
Expert:  Charles replied 1 year ago.

Hello, my name is***** will assist you today.

Do you know what octane fuel the engine is running on?

Have you noticed a whistling sound from the engine at all?

Do you know any of the history on this engine?

Customer: replied 1 year ago.
90 Oct. Marine fuel (no ethanol), no, owned engine since new in 2008. Only Port engine surging last 60 to 80 hours. Both engines port and starboard have 919 hours on them.
Expert:  Charles replied 1 year ago.

Ok, there are a few things that can cause this kind of problem on this engine. There were several bulletins over the years that should have been completed on the engine. A few items for you to look at are;

The clamps on the front of the engine that hold the throttle body on. They should be stainless and not rusty. If rusted, this could allow excess air into the supercharger.

The rubber boot on the MAP sensor. This is on the rear left of the engine when looking down from the boat. There is a sensor there with 3 wires going to it. Inspect the rubber boot for tears.

The 2 knock sensors located behind the charge air cooler. They are mounted directly to the block. Make sure that they both are still tight.

Let me know what you find.

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