Yanmar 1GM10 changes tone and has less power

[slawosz]

Hi,
I noticed around 15 engine hours ago that for few seconds engine sounds like old tractor on low revs, power is the same but cant accelerate - nothing chages. It was every 30 minutes or so but now is half of the time. Lower revs are fine. Bit worried as I am in the middle of the trip. I wonder if it sounds like filter clogging? Filters changed around 3 weeks ago and engine was running 50 hours since.

 

[LittleSister]

Yep, very likely primary fuel filter clogged.

(Especially as you're in the middle of a trip, because (i) fuel getting sloshed around the tank surfing up muck and debris; and (ii) gremlins are always tempted when you are trying to make progress!)

With partially blocked fuel filter it will run OK if you are drawing limited fuel past the filter at low boat speed - that much can fuel can get through - but try to draw more and the engine uses up what's available to it faster than replacement can get through the filter and then engine becomes starved.



Doesn't matter how long ago, whether weeks/months or engine hours ago you changed it, change it again now (and inspect the inside of it if its the type you can). At worst it will eliminate that as the potential source of the problem. At best it will completely solve the problem for good. Quite possibly you have fuel bug and a new filter will be ok for a bit, then get clogged again.

 

[slawosz]

Thanks. It was primary filter. Black fuel in bowl and lot of debris. I was lucky as was motoring entire morning (doing amazing 2kts sog) and engine died when I was about to turn it off as finally cleared The Looe.
Engine is very happy, I still need to sort muck in tank though.