yamaha 0x66 fuel pump - question

[bigguy]

I am trying to troubleshoot , boat runs for about 2 min. at 4000 rpms before the fuel pump shuts down and the engine stalls. You can start it back up and it will do the same thing again. I jumped the voltage regulator to the fuel pump and the same thing happens. If the fuel pump was bad wouldn't it just stall right away? Any ideas or suggestions would be greatly appreciated. :evil:

 

[John_Madison CT]

I'd hook up a fuel pressure gauge to see if your pressure drops. You can buy them at NAPA, Autozone, etc. etc... They hook up to the schrader valve on the VST filter.

When was the last time you checked your VST filter??

 

[bigguy]

I have 35 pounds then it just drops to 0 and stalls. If it was the vst I think it would drop to about 2000 rpms ?

 

[HM5]

If this has the box style low pressure fuel pumps, the diaphrams in them are shot. Had to replace both of nine on a HPDI engine last fall for the same symptoms.

To test, remove the 2 bolts holding them on the engine. Leave the fuel lines connected, and squeeze the primer bulb. If you see fuel leaking out of the back side of the pumps, replace them.

Check with Andy at Shipyard Island Marina, got mine for 20% off.

hope this helps

 

[TomS]

You can also try pumping the primer ball when the engine starts bogging down to see if that gets it going again. If it does, then its the LP pumps, as suggested above and a very easy (and inexpensive, if such a thing exists) fix.

-- Tom

 

[bigguy]

Thanks ,I will give it a try

 

[Capt Bill Welder]

When you turn the key to the on position the VST pump will cycle. You can hear it.
When was the last time you cleaned/replaced the filters in the VST pump?

 

[bigguy]

The vst filter was the first thing I replaced. I am going to check the LP pumps today.

 

[bigguy]

replaced lp pumps running great now thanks

 

[HM5]

Glad to hear it, bigguy. Amazing when those little ba$%ar!s won't pump enough fuel to keep the fire lit.
One more thing, I bought some aftermarket diaphrams, and rebuilt the housings I took off. Put them on the shelf just in case the new ones take a dump. If the boat ever presents those symptoms again, it won't take long to diagnose, and I can put them on while waiting for factory pumps.