2005 Yamaha 300 hpdi will not get above 4100 rpm

tdxbunger

Cadet
Joined
Jun 23, 2007
Messages
13
Two weeks ago, at the end of a day-long trip, the engine lost rpms and the boat fell off plane. When I gave it addtional gas to get back up on plane, the rpms would not rise. Turned off, checked prop and no problem. Fired up and was fine.

Took out again last night. Fine for 45 minutes or so, but then same problem. Turned off, waited, turned back on. Fired up and went to max rpms fine. 30 mintues or so, same problem.

This morning, it would not get past 5,000 initially and then would not get past 4,100 the rest of the way back (1 hour or so).

Engine just had annual service prior to first trip. I checked filters and no water. The fuel flow meter indicated over twice the fuel being used. I assumed I needed to recal the meter. Maybe not, though.

The batteries should be fine. The temp guage never even registered the engine getting hot.

Any ideas?
 

Ray Neudecker

Lieutenant Commander
Joined
May 25, 2004
Messages
1,656
Re: 2005 Yamaha 300 hpdi will not get above 4100 rpm

first check for a problem with the anti siphon valve in the fuel tank.
 

JUSTINTIME

Captain
Joined
Sep 2, 2006
Messages
3,284
Re: 2005 Yamaha 300 hpdi will not get above 4100 rpm

did primer bulb go flat?
drain the vst and see if any debris come out
 

tdxbunger

Cadet
Joined
Jun 23, 2007
Messages
13
Re: 2005 Yamaha 300 hpdi will not get above 4100 rpm

Primer bulb did not go flat, but it did not get very hard.
 

tdxbunger

Cadet
Joined
Jun 23, 2007
Messages
13
Re: 2005 Yamaha 300 hpdi will not get above 4100 rpm

Update:

Thanks for the suggestions. It was a fuel delivery issue, and the first one I checked: the fuel filter. However, I did not check it well enough because we ended up checking the venting, gas tank pick up, anti-siphon value and a couple of other things.

It ran fine on a remote tank and then we bypassed the filter and it ran fine.

I will be keeping at least one extra on board at all times now.

Adam
 
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