yamaha 300 hpdi

angler0520

Petty Officer 3rd Class
Joined
Jun 24, 2009
Messages
76
i have a 2004 yamaha 300 hpdi i went to the keys for mini season and filled my boat up at a marina several times there when i got back home i have been having problems with my motor if i try to get up and go very quickly the motor just falls on its face i can get up on a plain if i really ease into it but once on a plain it will not go over 3200 rpm and it runs very rough at 3200 like it is not getting enough fuel does anyone have any ideas i nead help bad

i have put it on a 5 gallon tank with new hoses all the way to the motor to rule out the gas tank and have changed the plugs but i dont know what to do next
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
Re: yamaha 300 hpdi

If you are thinking fuel problems you need to look at your fuel pressures and clean/ change the screens and filters. Maybe even have the injectors tested and cleaned.
Running lean will eat pistons and cylinder walls
 

angler0520

Petty Officer 3rd Class
Joined
Jun 24, 2009
Messages
76
Re: yamaha 300 hpdi

yes sir i was thinking about the high pressure fuel i just need to get ahold of a gauge to test it with do you have any idea what kind of psi i should have?

and when you say screens im not sure what you mean
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: yamaha 300 hpdi

there is a filter in the VST that requires maint as well as a medium pressure inline filter between the VST and the high pressure pump that also requires maint.
DO NOT use a standard hose clamp on the inline filter.
use ONLY the correct clamp with the correct tool to install it.
run that engine much running lean and you will find out about powerhead replacements.
while you have the hood off look at the oil pump arm, post the numbers on the arm.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
Re: yamaha 300 hpdi

Do a forum search and read up on HPDI s.
Rodbolt is the guy that knows Yamaha s he is a Master tech so pay attention to what he says as you read.
here is one of his replies, but there is a lot more info he has put out there if you just look.
http://forums.iboats.com/showpost.php?p=969252&postcount=14

never mind Rodbolt found you while I was typing.
 

angler0520

Petty Officer 3rd Class
Joined
Jun 24, 2009
Messages
76
Re: yamaha 300 hpdi

thanks for helping rodbolt what psi should i see when i test the high presure? and what tool/clamp do i need for the filter between the vst and high pressure pump is it something that i can buy or is it a yamaha specialty tool?
once again thanks for all your help
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: yamaha 300 hpdi

the clamp, only part number I know is the one from a yamaha dealer.
the tool I use is a snap on CV boot clampinstaller.
medium pressure is 50 PSI at any RPM. high pressure is about 975 PSI minimum.
high pressure can only be checked with a laptop or a DVM checking orange to pink at 3.2V minimum.
 

champion203

Recruit
Joined
Jul 12, 2013
Messages
1
Re: yamaha 300 hpdi

I have an 04 300hpdi. I was going to change the basket filters and noticed that their is no basket filters on the inlet side of my HP pump. I only have 1ea. per injector. I did see pics of an 05 250hpdi that had the basket filters in the inlet of the HP pump. Is an 04 different or in a different location?
 
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