02' yamaha HPDI problem

[huurup]

I have twin 150 hpdi's. One of them looses power after a few minutes of +4000rpm, it will slide lower and lower and won't rise back up. Its just like a loss of power? If you turn the key off and wait a few seconds your good for another mile or two at +4000rpm. I have changed racors, vst filter, meduim pressure filter, fuel is good, bulb is firm when problem occurs, electric pump holds at 50 psi . I have run the yami software and it shows low pressure on high pressure pump when problem occurs, i want to understand how by turning the key off this will temporarly fix the problem?
All other info on the computer shows well with in ranges, o2 sensor may be a little off, low if any thing, which would confirm whats going on inside. Any ideas will great! Has anybody replaced a high pressure pump? What were the syptoms?
Thanks for your help!

 

[Bob Gale]

Re: 02' yamaha HPDI problem

Yes, I had a problem similar to yours. All the same symptoms and it showed the HP dropping to about 50# from 750# when the problem occured. I replaced the HP pump and it's pressure regulator and the problem went away. Expensive, around $1200 or so from a discount parts place, actually here I think. Before you go that drastic, I would try removing the 4 (I think 4) tiny screens and soaking them in something like Sea Foam then blow them out. To remove them just screw a sheet metal screw in and pull it out. I can't find any source to buy them. It's worth a shot if your going to replace it anyway. After looking at my old one I found one clogged screen, but never put it back on to test it. I know I'll get lambasted for my advice by the pros on here, and they are good but none of them steered me to the HPP. You can check out my thread by searching "Help, Yamaha 150 HPDI, engine surging" or under Bob Gale. Oh, I have heard that a place in Florida rebuilds the pumps.

 

[rodbolt]

Re: 02' yamaha HPDI problem

its cause bob never mentioned the loss of High pressure fuel.
can be tested with a laptop or a simple multimeter.
Flagship marine in punta gorda FL can clean and test the HP pumps on that motor.
and sometimes ,as I just got married and bought a house all in the last 6 months, I actually miss a few threads. sorry.

 

[rodbolt]

Re: 02' yamaha HPDI problem

have you changed the medium pressure inline filter?
you MUST use the special clamps not a standard hose clamp or a wire tie when changing this filter.
part number is 60V-24251-01-00. cost about 80 dollars and the clamp is about 10.

 

[huurup]

Re: 02' yamaha HPDI problem

I have changed it! It aint cheap and niether is the clamp!
How does the fuel regulator work? It did read 70 psi at one time, does that indicate a restriction before the high pressure pump?
I have had this problem or similar before and new filters took care of it! This time its got me puzzled!
Thanks for your help!

 

[rodbolt]

Re: 02' yamaha HPDI problem

with a known good medium pressure inline filter simply monitor both the VST fuel pressure and the HP pressure.
if the VST stays good and the HP falls then send your pump to Flagship marine, we just got the bulliten from them a few weeks ago that they offer HP service.
no service parts for the HP pump are avalible from yamaha.
and yes there are 2 filters in the HP pump.