RPM Loss

[mike sylvestri]

I have a 1999 Shamrock express with a Yanmar 4LH-DTE. Recently I have lost 4 rpm and about 4-5 mph. I have changed the fuel filters, air filter, and made sure the bottom and running gear is clean. Nothing has changed. The engine runs fun. no blue, black, or white smoke when running. I have no idea what it can be. The prop seems to be in good shape although I think its fairly old and has been reworked a few times. Is it possible that it’s past it’s useful life and stopped performing one day? Appreciate any help and ideas.

Topic

[Tony Athens]

Mechanical throttle linkage issue?

Post pictures of the engine as installed in the boat–All angles/all perspectives, Clear & in-focus

Tony

[Rob Schepis]

Figured that would be the case based on the title of your post but wanted to be 100% sure as loss of speed with loss of rpm is a different animal than loss of speed without loss of rpm..

Have you seen this and gone through it?

Understanding Low Power Troubleshooting

[mike sylvestri]

400 rpms and 4-5 mph

[Rob Schepis]

Hello Mike. Please clarify – she’s lost 4 rpms? or 400 rpms?

[Author]

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