how to replace a low pressure pump on a 2001 larson 270 with 5.7 GSI VP

[freelancer]

Hello all, 1st time post but I've been reading for a while now. I have been dealing with a loss of RPMs after about 1300 while under load only. When I drop the engine down around or below 1300 RPM it runs fine, idle and neutral rev up to 4500 RPM the engine runs fine. I have read some other post that described testing the fuel system and my problem is very similar to some of you that went with either replacing the pumps (hi and low pressure) individually or replacing the entire fuel cell. I have already replaced the Hi pressure pump with the Volvo Penta replacement pump but that did not solve the problem. I'm ready to replace the low-pressure pump with the Sierra part number 18-7331 (cant part with the $700 for the whole fuel cell). Replacing the low-pressure side doesn?t look as strait forward as the High pressure side was. Does any one the steps involved in replacing the low-pressure fuel pump? Steps already taken to resolve low rpm issue: replaced fuel separator 3 times, tested fuel for water (none found), new rotor, new plugs, new wires, new distributor cap, dry gas added to tank, new hi pressure fuel pump. Please advise. Freelancer

 

[Don S]

Re: how to replace a low pressure pump on a 2001 larson 270 with 5.7 GSI VP

Sounds like you are having a lot of fun wasting money on pumps that probably aren't your problem.
Have you ever checked the fuel pump pressures? How about running the engine on a diagnostic tool? Your ECM may be telling the the engine to slow down for some reason. I assume you have been reading the OEM diagnostic manual haven't you?

PS, what is your full model number or SN for the engine. Year doesn't mean much.

 

[freelancer]

Re: how to replace a low pressure pump on a 2001 larson 270 with 5.7 GSI VP

Thanks Don for the reply,
I did write down the SN but it?s on the boat right now, going down this weekend and will get it then. I do know however, the model is a 5.7 GSI PEFS, and the fuel system has the twin throttle body injection system.

To answer your specific questions, no I have not checked the fuel pump pressures or run the engine on a diagnostic tool. I purchased the boat used in the spring of 2006 and I'm not really sure of the prior owner approach to maintenance outside necessary repairs and winterization. The plugs were Delco brand so maybe they were replaced in the past but for the rest of the "tune up", it was probably past due, especially the distributor cap that totally caked up inside. This week I purchased the Seloc manual with the online access for a year. I would like to get a little more familiar with my engine but I haven?t gotten there yet and I don't have many specialized tools. Also, the hi pressure pump was winning most of last season and just got louder until I replaced it, there was a small amount of build up on the screen. Freelancer.

 

[Don S]

Re: how to replace a low pressure pump on a 2001 larson 270 with 5.7 GSI VP

Here is a link to the manuals for an EF model. You need manual 2,4,and 5 as they are listed.
http://www.4shared.com/dir/14518190/c08a758e/EFsharing.html

And one of these so you can listen to the engine.
http://www.rinda.com/marine/mtspec.htm

 

[freelancer]

Re: how to replace a low pressure pump on a 2001 larson 270 with 5.7 GSI VP

I'll take a look at the links; hopefully they will help. Thanks-Freelancer.