350 MPI Tow Sports "cutting out" at 3000-4000 RPM

[deisenhauer]

Runs fine at lower RPMs, but stalls out above 3000 RPM. Just started doing so recently. In-line fuel filter and fuel/water separator replaced which helped some (was stalling at lower RPMs at times before replacement). Engine is in a 2003 Tige Rider's edition with under 300 total hours. Any suggestion on items I can try myself before brining it in to a dealer?

 

[Bondo]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

Ayuh,... Welcome Aboard,... Sounds like Bad fuel, or Water in the fuel, or the fuel system already has a load of Crap in it,...

 

[deisenhauer]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

Ayuh,... Welcome Aboard,... Sounds like Bad fuel, or Water in the fuel, or the fuel system already has a load of Crap in it,...

Thanks. So would you suggest anything other than replacing the fuel to begin with? Any additives to clean the fuel system?

 

[Bondo]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

Thanks. So would you suggest anything other than replacing the fuel to begin with? Any additives to clean the fuel system?

Ayuh,... How much crap was in the fuel filters ya took off,..??

Additives won't fix fuel that's already Bad,...

Ya gotta clean the fuel system, 'n start fresh,...

 

[deisenhauer]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

That's the next step, siphon out all the gas an put in clean. The filters coming out were pretty clean actually, with some water in the separator.

 

[Bondo]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

That's the next step, siphon out all the gas an put in clean. The filters coming out were pretty clean actually, with some water in the separator.

Ayuh,... You've Id'ed the Problem,....

Now ya gotta figure out where the water came from, so's it don't happen again, 'n get rid of the water ya got now,...

You can probably get most of it by pumpin' off the bottom of the tank,....
Water is way heavier than gasoline,...

 

[deisenhauer]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

Ayuh,... You've Id'ed the Problem,....

Now ya gotta figure out where the water came from, so's it don't happen again, 'n get rid of the water ya got now,...

You can probably get most of it by pumpin' off the bottom of the tank,....
Water is way heavier than gasoline,...

No Joy! Fresh gas give the same result. Think my next step is taking it in to get looked at unless you have another suggestion?

 

[Bondo]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

No Joy! Fresh gas give the same result. Think my next step is taking it in to get looked at unless you have another suggestion?

Ayuh,.... Fresh gas in the same tank,..?? with the same filter,..??

Hookin' up a remote tank to the filter, after it's checked, 'n changed will eliminate the tank,...

 

[deisenhauer]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

To close this out, the problem ended up being a bad fuel boost pump dropping pressure at higher RPMs. Replaced pump and works fine. Thanks for the suggestions!

 

[Bondo]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

To close this out, the problem ended up being a bad fuel boost pump dropping pressure at higher RPMs. Replaced pump and works fine. Thanks for the suggestions!

Ayuh,.... Glad to hear ya got it sorted out,....

How 'bout the water in the fuel issue,..?? that may well have helped kill the primary fuel pump,...

 

[agallant80]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

My friend killed his booster pump because of water in the fuel.

 

[deisenhauer]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

Bond-o, don't know that there was water in the tank as I had emptied the gas and replaced the filters. It very well could have been a contributor to the pump failing. There's no indication of any way water could get into the tank, no leaks, no standing water every around the tank so it would have to have been from a bad source at some point. I try not to by gas on the water, will be even more diligent going forward!

 

[achris]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

If you live in a high humidity area it could be coming in just via the air pumping in and out of the tank during the day. As the fuel heats up during the daytime it expands, forcing air out, then at night it cools and sucks moist air back in. The water in the air hits the (relatively) cool fuel and drops out of the air and into the fuel. Just a few mills, but as the days go by that adds up....

Easiest way to avoid that, is to keep the tank topped up... Less air volume for the tank the 'breath'....

Chris......

 

[Bondo]

Re: 350 MPI Tow Sports "cutting out" at 3000-4000 RPM

Bond-o, don't know that there was water in the tank as I had emptied the gas and replaced the filters. It very well could have been a contributor to the pump failing. There's no indication of any way water could get into the tank, no leaks, no standing water every around the tank so it would have to have been from a bad source at some point. I try not to by gas on the water, will be even more diligent going forward!

Ayuh,.... Go ahead, 'n run it,... I'd just pull the fuel filter on occasion, 'n inspect it's Contents,...

I fought water problems on a couple of hulls, that went back to tank Vent lines installed without an upward loop,...