2005 150 HPDI trouble

[skyduck]

Have the same problem that others have been having slugish out the hole down from 5500 to 4800 rpms.
Changed plugs, fuel bulb, changed vst filter, fuel-water sep under cal, screen under pump in vapor sep, 1/4 screen behind regulator. Ran boat for an hour with no problems only to return next day and problem is back. Motor cranks idles and runs smooth just acts like I haven't got gas to it. Pulled plugs one at time so haven't lost one. Cut fuel lines at bulb change don't seem to be coming apart. Can't find any leaks but bulb doesn't stay hard.(never messed with so not sure this is normal or not)Don't have 10 micron so I guess it's possible I have trash in tank and did it again though I didn't find much on screens first time. Any Ideas? I guess one test would be to run small external tank and see what happens.

[Rich Z]

Did you change the fuel strainer and did you check the lift pumps?

[skyduck]

Yes I changed the strainer, please elaborate on the lifts.

[Rich Z]

There are two low pressure pulse fuel pumps that are bolted to the side of the block. They supply the fuel to vst. Unbolt them from the block and squeeze primer bulb. If fuel leaks out from the back, then you need to replace the diaphragms or the whole pump. The fuel injectors may also need service.

[skyduck]

Can you explain why after changing screens and filters I was able to run with no problems for an hour. Return next day and the bogging down has returned? Not questioning your suggestion just trying to understand.

[Charlie206]

That's an excellent question. The answer can be pretty hard to come by however. Intermittent problems are the hardest to find. Rich gave you very good advice - check the lift pumps. Without having all the necessary testing equipment, it is a process of elimination finding the problem.

[Rich Z]

You doing the right things. Like Charlie said a lot of the times it’s a process of elimination. Most fuel related problems will not be detected even by DDT. Checking these lift pumps is easy and won’t cost you a dime unless you tare a gasket that typically is stuck to the block. There are also four little screens in the fuel compressor pump that can cause problems. The fuel tank pick up tube has a screen and injectors also have screens. Any of these can cause problems. Lift pumps are the most problematic. The initial run can be fine and when motor sits for a short time the fuel will leak into the crankcase casing a flooding condition. It all depends how badly thorn are the diaphragms. I experienced a complete WOT shutdown before due to bad LP but stared up and idled fine.

[skyduck]

Update. Took the first one loose just pulled it back from block without taking it off and pumped bulb. Saw gas leaking from one of the 4 screw holes not the back. Put a screw driver on the screws and could tighten them with 2 fingers. Pumped the bulb and no more leak. I did not pull the vapor seporater to check the other one but took the boat out and ran it. Ran great. Hopefully that was it. Thank you so much for your help.

[Rich Z]

maybe just an air leak

[Charlie206]

Go ahead and try to tighten the screws of the other one if they seem loose, if you can get to them. Use a 90 degree screwdriver if you need to. Glad to hear it seems fine.

[skyduck]

Update again. Ran the boat yesterdayfor a couple hours and everything was fine, then it started again. I came home pulled both lifters and pumped the bulb found nothing coming out of either. Tightened all screws and ran it today same thing right from the start. Slugish out the hole 4700/4800 rpms tops. I have no idea what to check as I belive I got all the filters so I guess the next stop is the shop unless someone has an idea.

[Rich Z]

http://www.bbcboards.net/zerothread?id=630903
First post on top of this page

[skyduck]

Rich, If while checking the lifters if I damaged the gaskets on the back of the lifters would that cause the lifters not to work right and give the result I'm having. Also, I hate to say this but when I changed out the primer bulb I replaced it with a Bass pro one. Could that be it? I'm just trying to elementate everything posible before getting into the little filters or shop.

[Rich Z]

Bad gaskets on lift pumps must be replaced to eliminate air leaks into crank case. This can cause all sorts of problems. The fuel line bulb should be fine as long as the directional arrow is pointing the right way and either pointing horizontal or up. The high pressure pump screens are the most likely culprit to your problem.

[skyduck]

I replaced the bulb with an oem mercury bulb ran the boat and it ran great. I'm not getting my hopes up as I've been here before but the bulb goes hard and stays that way where it didn't before. If I have any more trouble I'll be contacting you about the screens.

[skyduck]

I'm still having trouble. Ran the boat last weekend and it ran good for about 12 miles. I stopped and fished a while and when I started back up it started acting up again. Slow out the hole and drop in rpms could only get 3900rpms. I don't understand why I can ever get full rpms with a fuel restriction and why it doesn't buck sputter or hesatate. Rich if you still think it's the screens could you please tell me how to go about ordering them and what else would you suggest getting while I do this. What are the "pipes" you talk about in your post?

[Rich Z]

Im sent