Yamaha hpdi 150hp please help

[thrasja]

My engine will run fine right off the trailor and after running and fishing an hour or so I can crank to move again and it will not get above 3200 rpms I can cut it off and let it sit a minute or 2 and it cranks up and runs fine like nothing is wrong .I have had it looked at by 3 different "yamaha PROS" and no one has fixed it yet .The following has been done to the boat all new filters including vst cleaning and all new fuel lines to sight glass on engine from the on board tank .Checked the fuel pressure from vst and it was 50 psi with the problem occuring.Low pressure pumps have also been checked out good .If someone out here has had this problem could you please give me some ideas on what else it could be I have spent about all I can for mechanics to guess and it not get any better. Thanks

 

[rodbolt]

Re: Yamaha hpdi 150hp please help

what is the high pressure fuel rail when the problem is occuring?
any codes set when the problem is occuring?
do the "pros" have fuel and electrical certificates on the shop wall from Yamaha training?
post a model number as the single driver Z motor is a bit different than the dual driver model.

 

[thrasja]

Re: Yamaha hpdi 150hp please help

Its a VZ150TLRZ I dont know how to check pressure at the fuel rail is it the silver allen set screw at the top of the rail is that a pressure port ?So far everyone that has checked it said it has not had any codes logged into the computer at all .None of them have experienced the problem they say its fixed and I get to the lake and its not fixed so I just started reading manuals and post and checking the stuff I could myself just trying to rule out some stuff . I couldnt afford to keep paying $300 to $400 dollars for people to guess at it I just dont have the money .I appreciate any help or directions I can get .No one around here has ever heard of one doing this. Thanks for your time

 

[rodbolt]

Re: Yamaha hpdi 150hp please help

the VZ tells us its a bass boat motor the last Z tells us its a 2001 model that uses a single injector driver.
the hpdi is a relativly complex engine and a lot of freshwater dealers simply have no experience with them.
to check the medium pressure you use a pressure gauge attached to the schrader valve on the VST.
to measure high pressure you either use the laptop or the test harness with a digital multi meter.
what area are you in and have you tried the yamaha dealer locator function to find a dealer with a master tech in your area?