2003 F115 Stalled, no fuel pump noise...next morning runs great again

[TryItNow]

I have a 2003 F115TLRB with 110 hours on it, original owner is me. The boat has run flawless other than last year I had to have the injectors sent out to be cleaned, cleaned VST, filters etc. It ran great for over 20 hours since then.....

This year after about four months storage (warm California indoor storage) the boat cut out a little. I removed all fuel, added new fuel with additives as usual, all seems well ..ran for a few hours fine after that. Well last time I took it out, it totally turned off under power and would crank but no start...got towed in. Trying to start while towed it sputtered and idled only for a second, then totally turned off...no fuel pump.

That night on the trailer, on ears, crank but no start several attempts. No fuel pump priming AT ALL When turning key on, but I would get the IAC noise. I let it sit for the night and thought I'd diagnose further in morning. In morning, turn key on, fuel pump primes perfectly, everything seemed ok again....so it was not able to be diagnosed.

What do I have to look at...I was thinking maybe main relay acted up? (68v-81950-00-00) or maybe the high pressure fuel pump was acting up,....but it now sounds perfect and I ran the boat two more days about 10 miles and ran perfect, no bogging, no nothing. Any ideas before I throw a part at it or am I going to have to do the dreaded wait till she quits again?

Thank you, I've been lurking on here forever finally have an issue that has me worried.

[pstephens46]

My 2 cents. Boats sits for long periods of time. Very low hours. CA, as far as I know, only has ethanol available. Symptoms point towards fuel contamination. Fuel system needs to be cleaned from tank through injectors. You need to use that boat way more often. You have to cycle that ethanol. The more you use it the better it will run.

you should only hear the ISC valve at key off. That may be an issue also. Verify that also.

[TryItNow]

Ok, I should have been more clear. I bought the boat in 2014 from first owner (family) from texas, and addressed fuel issues when I started using it. I have put 40 hours on it since then. Wouldn't, though, the fuel pump still cycle on with key on? I was getting no pump...and no psi, and no start. Even bad fuel wouldn't effect that? (I'm asking as I don't believe so but not sure)

[pstephens46]

Yes I believe the pump should cycle at key on just as my F150. I can’t hear mine unless the cowl is off. You need to get a fuel pressure gauge to check pressure at key on and running.

[TryItNow]

Yes it now runs perfect..pump cycles at key on for a second to prime system. When I had the stall and no start pump was NOT running even at key on ....after sitting it now runs fine again. Bad fuel shouldn’t make pump not work right?

[fairdeal]

Bad fuel shouldn’'t make pump not work right?

"bad fuel" is a broad term

at an extreme, "fuel" which results in water inside the VST will certainly make the pump "not work"
but in that case,
I doubt its going to "get better on its own" - overnight! and start "working fine" again.

[pstephens46]

It probably will show up again. You may need to dig into that VST again to look for corrosion on pump, etc.

[TryItNow]

yes, I understand bad fuel may make the pump "not work" but I'm not talking rusty fuel, I'm talking fuel which may have gone bad after a couple months or so (still a liquid). Yes I will see if it shows up again, I'm always under the impression the pump works or it doesn't but if there's junk in it or corrosion, or burnt up wiring terminals then I'll know what happened. Hopefully next time it acts up it doesn't get better letting it sit over night and I can diagnose it...it sure seems odd letting it sit made everything work hunky dory again. I have seen the posts about IAC valve...but not sure it would give the condition where pump does not prime at all at key on. The float in the VST....where does the fuel go when it fills up? I imagine the pump keeps running all the time...I dont' have the motor in front of me to see where the lines go and my memory doesn't serve me.

[pstephens46]

yes, I understand bad fuel may make the pump "not work" but I'm not talking rusty fuel, I'm talking fuel which may have gone bad after a couple months or so (still a liquid). Yes I will see if it shows up again, I'm always under the impression the pump works or it doesn't but if there's junk in it or corrosion, or burnt up wiring terminals then I'll know what happened. Hopefully next time it acts up it doesn't get better letting it sit over night and I can diagnose it...it sure seems odd letting it sit made everything work hunky dory again. I have seen the posts about IAC valve...but not sure it would give the condition where pump does not prime at all at key on. The float in the VST....where does the fuel go when it fills up? I imagine the pump keeps running all the time...I dont' have the motor in front of me to see where the lines go and my memory doesn't serve me.

Fuel gets cycled back to pump when VST is full. I have seen pics of corroded pumps from ethanol left in the VST for too long without running. Corrosion could lead to the pump motor seizing intermittently I would imagine. Could be an electrical issue also. But I am a pessimist. Time will tell

VST image.JPG

[TryItNow]

Fuel gets cycled back to pump when VST is full. I have seen pics of corroded pumps from ethanol left in the VST for too long without running. Corrosion could lead to the pump motor seizing intermittently I would imagine. Could be an electrical issue also. But I am a pessimist. Time will tell

VST image.JPG

Wow that doesn't look good. Do you have any idea how long the fuel sat in there? I parked this boat indoor storage in November, brought back out in April and this is when I had the hiccup with the fuel pump not coming on. I believe there is a drain on the VST on my motor, is that something that should be done, or is it the whole...is it better to be submerged or not debate I always get with race carbs on my cars? Thank you for your time on this!

[pstephens46]

*** that doesn't look good. Do you have any idea how long the fuel sat in there? I parked this boat indoor storage in November, brought back out in April and this is when I had the hiccup with the fuel pump not coming on. I believe there is a drain on the VST on my motor, is that something that should be done, or is it the whole...is it better to be submerged or not debate I always get with race carbs on my cars? Thank you for your time on this![/QUOTE]

I pulled that pic from internet so I don't know how long. I don't know for sure if you have this issue. What concerns me is a low hour 15 year old motor in a state that only allows ethanol fuel.

[TryItNow]

*** that doesn't look good. Do you have any idea how long the fuel sat in there? I parked this boat indoor storage in November, brought back out in April and this is when I had the hiccup with the fuel pump not coming on. I believe there is a drain on the VST on my motor, is that something that should be done, or is it the whole...is it better to be submerged or not debate I always get with race carbs on my cars? Thank you for your time on this!

I pulled that pic from internet so I don't know how long. I don't know for sure if you have this issue. What concerns me is a low hour 15 year old motor in a state that only allows ethanol fuel. [/QUOTE]

Yes, I bought it in 2014 with 80 hours on it, it spent its first 11 years in TEXAS. I use it wayyy more than the original owner did, who is family. I did the whole fuel system in 2016....injector cleaning, vst vilter, all other filters and has ran flawless till this year after a few months in storage.

[TownsendsFJR1300]

Draining the VST would show any water / junk settled inside.. Of course catch what comes out in a clean container...Pump the primer too while the valve is open.

I gather the pump inside the VST was not corroded visibly on the outside, (or elsewhere) when you last had it apart.


Remember too, that years of sitting, any water collecting inside the VST will cause corrosion. You may have gotten a piece stuck in the pump and it dislodged..

You didn't mention draining and cleaning the fuel tank. It's very possible crap (sitting in the bottom of the tank) got sloshed about and picked up into the fuel system (pump)

[TryItNow]

Draining the VST would show any water / junk settled inside.. Of course catch what comes out in a clean container...Pump the primer too while the valve is open.

I gather the pump inside the VST was not corroded visibly on the outside, (or elsewhere) when you last had it apart.


Remember too, that years of sitting, any water collecting inside the VST will cause corrosion. You may have gotten a piece stuck in the pump and it dislodged..

You didn't mention draining and cleaning the fuel tank. It's very possible crap (sitting in the bottom of the tank) got sloshed about and picked up into the fuel system (pump)

Yessir I didn't mention, the tank is very tough to get to (plastic) but I did siphon it and visually inspect with nothing out of the ordinary seen..looked very clean. When I cleaned VST, the filter was spotless and the tank looked great...the pump looked like new on the outside.

I'm with you on junk lodging in the pump then dislodging...I'm going to drain it and pump the primer to see if something comes out. Until it acts up again, I have to almost wait and see as any diagnostics aren't good at this point. I should remove an exterior fuel line and make sure it's not breaking down. I was just stumped on the pump not working at all, then the next working all is fine again. Maybe it got hot and seized up because junk was in it, who knows. It was acting a little funny before it turned off, and restarted for only a few seconds so it may have been passing some trash through

[pstephens46]

All speculation at this point. I wouldn't go crazy taking things apart. See if the problem shows back up.