Engine Over Revs At Idle

[RAD]

I have a Westerbeke W30 and over the summer while cruising it would race up for 10 seconds and go back to normal.....and I was afraid it would get worse so todays problem while running it in the slip to get the oil warm for an oil change it would slowly creep up in RPM's without me being near the throttle and if I shut it down and restart it would idle fine and do the same thing
I'm thinking bad injectors or one out of the four......me thinks it might be dribbling fuel and not spraying
anyone been through this?

[delmarrey]

There are multiple things that could cause this. First thing Id check would be the resistance in the throttle. Other things maybe fuel in your oil, air breather is dirty, IP is out of adjustment and so on.

What testing have you done so far?

BTW Welcome aboard!

[flagorio]

My primary fuel filter at the tank turned out to be clogged with algae when I had similar symptoms.

[perchance]

Watch the linkage on the injector pump while the engine is doing it's thing. It could be a governor problem.

[Barnhard_Marine]

It sounds like your throttle is creeping disconect the throttle cable from the injection pump hold the throttle lever in the idle position. Does it still happen? If so it's in the governor assemble. If it doesn't go to home depot and buy an electrical cable clamp and put it on your throttle cable to tension it so it wont creep.

[RAD]

Checked for fuel in the oil and that was ok, looked at the throttle cable at the engine while running and nothing moved, I'm hoping its not something in the injector pump......my filters are clean and have a vacumne gauge to check that but what puzzles me is if you have a clog why would the engine over rev

[Barnhard_Marine]

You might also check for a clogged return line. Air in the main fuel line can also cause surging

[RAD]

Originally Posted by Barnhard_Marine

You might also check for a clogged return line. Air in the main fuel line can also cause surging

This is interesting because the only item I ever touch the fuel line is at the CAV filter on the engine and to get to the filter bolt I had to loosen the banjo bolt for the supply and injector return lines (there both together) I did look at that today and didn't see any fuel leaking so I ruled that out

[Barnhard_Marine]

That CAV filter system is prone to leaks I'd start there

[RAD]

Originally Posted by Barnhard_Marine

That CAV filter system is prone to leaks I'd start there

so an air leak would make the engine rev or behave erratically

[Barnhard_Marine]

That is correct always make sure that the "o" rings, sealing rings and coppers are replaced. always put a light film of grease on the "0" rings and sealing rings... Good luck PM me if the issue presist

[Stray-Cat]

Originally Posted by RAD

so an air leak would make the engine rev or behave erratically

Correct ......air in the fuel suction will cause the engine to speed up