2001 150 hpdi

[Scotakns]

Buying a boat with a 150 HPDI motor and after getting on plane the engine will stall. Starts back up and runs a distance and repeats this. It is running out of fuel. How many electric fuel pumps does this motor have? Both diaphram pick up pumps have been replaced.

[VectorPat]

It has one elec pump in the VST, pretty good chance the filter on it is plugged up and while you are changing it you might as well change all of the others.

[mrv8outboard]

There are two low pressure lift pumps, one electric in the VST tank and one belt driven. There are filters first one on the engine is 68F-24563-00-00 ELEMENT, FILTER. Next one is in the VST tank 68F-13915-00-00 FILTER. The last serviceable filter on the engine is between the VST and the high pressure pump 68F-24251-00-00 STRAINER 1. Also check for a water separating fuel filter in the boat.

The other thing I would suggest is to have it checked with the YDIS software.

[Scotakns]

I took it out today and every once in a while it will try to run pretty good and then it will fall on it's face. My question is if the high pressure pump was bad would it run at all?

[Superbender]

the motor will idle ,not very well with the belt off,just enough to get you home.I agree with vector pat check the fuel presure at the vst and replace the filters if you know someone with ydis that would be even better

[Scotakns]

I am going to check the filter in the vst tomorrow. What is YDIS? Is this a diagnostic tool? I am in the Dallas area if there is anyone here that I could talk to or pay to help. I am an automotive technician so I try to fix everything I can myself.
Thanks

[Scotakns]

Okay, I have taken the vst apart this morning and the filter on that fuel pump looks great and the tank was full of fuel. Can the O2 sensor cause this same syptom?

[Scotakns]

I checked the fuel pressure at vst fitting and I have over 50 psi. I took the o2 sensor out this morning and it is pretty nasty. Will this cause some of the symtoms I am having.? Is there anyway to check fuel pressure on the belt driven pump?

[Scotakns]

Can anyone help here?

[VectorPat]

Did you check fuel pressure at the time the engine would stall or just with the key on or running on a hose? It needs to be checked at the time the issue occurs or you will be chasing your tail. I would still have replaced the filter in the VST, many times they appear to be clean but if you let them dry out you might notice a film will form over the screen. It would also help to have a computer connected so you can monitor your pressure from the high pressure pump.

[Scotakns]

Fuel pressure was good when it stalls. I did this, I unplugged the o2 sensor for a minute and when I plugged it back up it seemed to run good for a short period of time. I am going to try and clean the sensor and tube and see what happens.

[VectorPat]

The O2 sensor is mainly used under 1600rpms and really isnt used after that. I have seen some running issues caused by them tho. Be careful cleaning as you might damage or contaminate it and create another problem.
I would still replace the filter that is between the VST and the high pressure pump and if you have anyway to get a computer connected to it you need to do that so you are sure you are maintaining high fuel pressure.

[Scotakns]

I have about 3 volts at the hp sensor which should be around 600 psi according to a Yamaha tech on another site.

[VectorPat]

I have never used the voltage to measure that so have no idea of that is good or not. You still need to check it when the engine is stalling. You should have around 750psi.

[hydrostream1]

Check the basics first,get an external tank hook the fuel line to the motor,go out and run it,if it does the same thing its not fuel supply,if it runs good,look at the check valve at the tank or pickup in the tank.

[Scotakns]

Where is the check valve at? I put new plugs in it today and took it out it ran great 5500 rpm's for a mile or so and then would start losing power and stall out, I could resart it and it would go again for a while. I tried an external gas tank, less than a gallon though so I'm not sure if that was enough fuel. But it seemed to do the same thing. I just can't see it being the HP pump if it runs good for a while like that. I plan on taking it to the dealer on wed. and see what the vds shows.

[Scotakns]

I found that the fuel pressure regulator was stuck closed and the dealer said that the medium pressure was high. Also said it had a code 16 clogged fuel injector or filter. Will the fuel pressure regulator cause a issue like this?

[mrv8outboard]

Check out these, there are some visuals there that may help.

hxxp://www.yamahaoutboardparts.com/forum2/hpdi-mechanical-high-pressure-pump-th10974.html

[mrv8outboard]

Check out these, there are some visuals there that may help.

hxxp://www.yamahaoutboardparts.com/forum2/hpdi-mechanical-high-pressure-pump-th10974.html

[VectorPat]

You can get a fuel injector code from low fuel pressure as the ECU doesnt see the load from the injector. I have seen this many time when someone runs out of gas. How high was the med fuel press?

[Scotakns]

Okay, here is the deal. I tested it today on the water and my med. pressure ramains at 50 psi no problem. I had a volt meter on the HP sensor wires and was told by a Yamaha tech that it should remain between 2.8 and 3.2 volts. It is about 3.0 volts when idling or revving up in neutral, but when I put it in gear and try to take off the voltage starts dropping rapidly. So I am assuming the high pressure pump is bad. Are these pumps repairable or do you just have to buy a new one? As much as one cost new you would think that they would last a lot longer.