Yamaha 2001 HPDI Issue

[jimnlouisiana]

I have twin 2001 Yamaha 200 HPDI outboards. One of them will occasionally only get to 3500 RPM at full throttle. Then if I simply shut the motor off for 5 seconds or so and restart, it runs great (gets all the way to 5300 RPM).

Why, when I shut it down for a few seconds, does the problem go away? What could be causing this? It is intermittant, so most of the days I run the boat the motor does not even display this symptom.

Jim

 

[cousinabe]

Re: Yamaha 2001 HPDI Issue

When was the last time the VST filter was cleaned?

 

[jimnlouisiana]

Re: Yamaha 2001 HPDI Issue

which filter is that? I have new fuel filters and I did change the filter in the cowling where the fuel comes in. Is the filter you are referring to on top of the motor that requires a special tool to replace it?

Do you think it could be something restricting fuel flow?

 

[cousinabe]

Re: Yamaha 2001 HPDI Issue

here are a couple of good posts regarding hpdi's.

http://forums.iboats.com/showthread.php?t=144600

http://forums.iboats.com/showthread.php?t=257011

 

[jimnlouisiana]

Re: Yamaha 2001 HPDI Issue

Thanks, those were informative. What is a VST filter. Is that the metal filter on top of the motor?

 

[cousinabe]

Re: Yamaha 2001 HPDI Issue

Sounds like you have a fuel starvation issue.
You don't want to run that motor lean like that for too long, otherwise you could blow a piston. Got to get the problem resolved.

Fuel restriction could be related to many things.
The above links go through methodical ways of testing this.

This link shows the VST filter being changed.
http://bbcboards.zeroforum.com/zerothread/66928

 

[rodbolt]

Re: Yamaha 2001 HPDI Issue

the VST filter is a screen inside the VST attached to the intake of the medium pressure pump. needs annual service.
the metal inline is a medium pressure(50 PSI) filter and needs annual replacement.
to replace it you have to cut the metal band clamp.
you MUST use a metal band clamp when replacing it.
DO NOT use a worm clamp as it can loosen with repeated swelling and contracting of the rubber at 50 psi.
if the short hose is bad DO NOT use a standard automotive fuel line as they are not designed for continuous use at 50 PSI.
a 50 PSI fuel leak is rather nasty.

 

[jimnlouisiana]

Re: Yamaha 2001 HPDI Issue

Update: I did have the VST filter cleaned. It did have trash in the screen and in the gas reservoir. (some kind of red liquid gasket material).

At first it seemed to have solved the problem. I shut the engine on and off a few times and the symptom reappeared. (Note: When I went to start the engine the first time, the battery was dead).

The mechanic from the Yamaha dealer asked if my battery was healthy and I told him that it had no charge when I went to start it. He said, the battery actually may be the issue.

I got a new battery and out of 12-15 starts and shut downs, the symptom only repeated itself twice. (Of course I was starting and shutting down every 45 seconds or so to test it).

Could the battery charge be why sometimes the motor would only get up to 3500 RPM, even with the alternator running?

 

[cousinabe]

Re: Yamaha 2001 HPDI Issue

what about the medium pressure filter? did you replace that as well?

still sounds like a fuel restriction issue.

 

[jimnlouisiana]

Re: Yamaha 2001 HPDI Issue

Yes, I replaced the medium pressure inline filter before I had the vst filter screen cleaned. (I assume that is the bronze color metal filter on the back side of the motor that takes a special crimping tool).

Could voltage (from the battery)have anything to do with the problem?