Lost Top RPM's

[Raymond W Smith]

Cummins QSL9-40 Ft. Sedan Trawler. Had prop reconditioned and the boat ran perfect. Couple days later i lost 50 RPM off the top end of 2100 RPM. Checked all fyel lines-Installed a complete new filter. It seems the boat runs nice until it hits about 2050 or 2060 and thats it. Engine & boat is ten years old and well maintained. 450 EH’s. Never had this problem before. Any comments or suggestions. Thanks

Topic

[Raymond W Smith]

Tony….Problem solved….As crazy as it may sound, the prop was coated with a heavy growth of thick slim. Never ever seen it like this before. I run the boat every week or so. It went from a clean prop to this in about a week or two. Others in the yard are finding the same thing. I have always used the best Micron Extra with the Bio. I did not think it was the prop since i just had it checked and tuned up. Boy was i wrong!!!! Thanks for all your help!!! Have a great day.

[Tony Athens]

Let’s start by you telling what you have for instruments?  Maybe a good picture of the dash?

Then I need to know what you have as to controls for the engine.

I need to know if you can check the following?

 

1) Max no-load RPM (neutral), engine warm, at the dock or at sea.

2) Throttle percentage (0-100%), instruments on, but the engine can be off to do this.

 

Tony

 

 

 

 

 

 

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