2009 Yamaha 225 HPDI Losing Power

[rickboat]

Been trying to track down why motor has lost power. Will not rev over 2800rpm. Doesn’t miss or sputter. So far I have changed VST filter, intermediate pressure inline filter, filter before low pressure pumps. Under running conditions, 2800rpm, intermediate pressure is solid at 50psi. High pressure is solid at 955psi (measured using the YDS 1.33.). I believe that the pressure sensor is on the port fuel rail. Compression at 113psi in all cylinders. Not sure where to go next. HELP please.

 

[99yam40]

have you looked at the read out to make sure the shift switches are operating?
HPDIs limit RPM when in neutral by cutting cylinders

 

[rickboat]

I did look at that. The YDS engine monitor shows the “shift position switch” toggle between on and off as I shift in and out of gear. Also can see cylinders 2 and 3 off in neutral and all cylinders firing in gear. All reported in the engine monitor.

 

[rickboat]

One more thing, the YDS also shows a “shift cut off switch”. It apparently is also in the remote shifter​​​​. What does it do? I don’t believe I saw it change state when shifting to forward.

 

[99yam40]

I believe it is to help get it out of gear

 

[rickboat]

I have used the YDS to fire each of the injectors. I can hear each one and they sound the same. Have also checked that I have spark but have not check strength of spark with a spark gap tester. If I have pressure of 955psi would that possibly indicate partially plugged injector(s)? Anything else?

 

[99yam40]

what are the specs for high pressure?
as long as rail pressure meets and stays in spec , it just says the pump and screens/filters are good

injectors also have screens in them that can clog up.
they can be sent off to be tested and cleaned just like the high pressure pump can be.
it also has screens/filters inside of it

need to be looking at YDS when problem shows up.
you can capture and save info for looking at later

 

[rickboat]

I think I'm going to send injectors out for cleaning, flow check, etc. Any suggestions as to where to send them?

 

[rickboat]

Sent injectors to Brucato for cleaning. In the meantime I am changing the basket strainers (secret filters) in the high pressure pumps. There are 2 in each pump. I was able to change the ones behind pipe joint item 29 on parts list since it came off with the cover. The other pipe joint, item 27 did not come out with the cover and stayed in the pump covering the filters. How can I remove these pipe joints without damaging the o-ring on the exposed part of the joint?