2004 Yamaha 115 randomly shuts off on plane

[Fishin]

Hey fellas months later and nobody could figure it out so far...so I’ve just been tinkering around on my own I’m not a mechanic at all so could be wrong but here’s what I’ve discovered. Tried running the motor on a portable fuel tank and the motor seems to run good! Okay great there’s my answer I went through the built in tank inspecting the anti siphon valve ect ect everything seems to be working as it should, put it all back together new valve motor still runs terrible. So just out of curiosity today I ran the motor from a new portable tank all new hoses and new fuel. Going from the portable tank though my fuel water separator new (filter) on that and motor runs terrible again. Ran the motor directly from the built in tank to the motor and the motor runs good? What I’m wondering is can the actual fuel water separator (housing) go bad? I’ve never heard of that but sure seems to be the issue.

 

[Bryan Allen]

Had a very similar issue with my previous suzuke when i first got it... They check pretty much all the above and went as far to change out the brain box a couple times... turned out to be a very small limiting type switch with injection system in the VST tank.. took a year to figure out but have not had a problem since..

Go to another shop--- the one you are using is wasting your money if they cant figure it out.

 

[Fishin]

Go to another shop--- the one you are using is wasting your money if they cant figure it out.

Been trying to get it in to an other shop but they all are pretty backed up, it’s booked to go in but still quite a few weeks before they can get to it so going to try a new fuel water separator for now and hope for the best!

 

[adrian1991]

Disconnect your fuel line from the motor and from your fuel tank
Have someone or plug the end to the motor and then put compressed air into the other end take a spray bottle with soapy water and spray around all connections

Sounds like it's getting air if it randomly shuts off and then it hard to start again.

Or run clear line from water separator to engine run it and watch to see if there are any bubbles showing up.

If nothing comes from that the next step would be to test your lift pump on the engine a shop should be able to scan for that I would hope.

 

[Fishin]

Disconnect your fuel line from the motor and from your fuel tank
Have someone or plug the end to the motor and then put compressed air into the other end take a spray bottle with soapy water and spray around all connections

Sounds like it's getting air if it randomly shuts off and then it hard to start again.

Or run clear line from water separator to engine run it and watch to see if there are any bubbles showing up.

If nothing comes from that the next step would be to test your lift pump on the engine a shop should be able to scan for that I would hope.

All the fuel lines are new, I actually did cap it off and blow air/soapy water everything seemed good. Motor was scanned no fault codes shown. New lift pump, injectors, vst cleaned new fuel filters plugs ect. Here’s where it gets interesting like I was saying I run the motor from the tank to the fuel water separator then it splits into 2 one for kicker one for main motor. If I run it directly from the tank to the motor it runs fine, run it though the fuel water separator motor stalls doesn’t start. So is it possible that the housing for the fuel water separator can go bad? The filter is new but the physical housing itself is only a year old, I’ve never heard of them going bad. Just interesting. Going on almost a year of this issue now

 

[Fishin]

This is how it’s set up. Obviously I’m missing a fuel line as I took it out to run the motor directly to a portable tank. To by pass this system.

 

[adrian1991]

All the fuel lines are new, I actually did cap it off and blow air/soapy water everything seemed good. Motor was scanned no fault codes shown. New lift pump, injectors, vst cleaned new fuel filters plugs ect. Here’s where it gets interesting like I was saying I run the motor from the tank to the fuel water separator then it splits into 2 one for kicker one for main motor. If I run it directly from the tank to the motor it runs fine, run it though the fuel water separator motor stalls doesn’t start. So is it possible that the housing for the fuel water separator can go bad? The filter is new but the physical housing itself is only a year old, I’ve never heard of them going bad. Just interesting. Going on almost a year of this issue now

Well if the housing was going bad you would of seen air bubbles when you did the compressed air and soapy water


Does it have one of those stem type filters in the center filter there is a 2" stem that protrudes down into the filter I know at work on a lot of machines if you don't pull that onring and change it it has issues when there is high fuel flow

 

[ship happens]

This is how it’s set up. Obviously I’m missing a fuel line as I took it out to run the motor directly to a portable tank. To by pass this system.

Is that the plastic moeller piece of absolute **** housing that they stop making?

Also I have not ready this entire thread, but from your original post.. If that thing turning off like a light switch its definitely not fuel related. i would check safety lanyard stuff and key switch.

Its either that or your battery cables. Loose your wing nuts if you have them also. Those engines will not run if disconnected from the battery

 

[Fishin]

Is that the plastic moeller piece of absolute **** housing that they stop making?

Also I have not ready this entire thread, but from your original post.. If that thing turning off like a light switch its definitely not fuel related. i would check safety lanyard stuff and key switch.

Its either that or your battery cables. Loose your wing nuts if you have them also. Those engines will not run if disconnected from the battery

I have no idea if it’s the plastic moeller you’re referring to it came with the boat. I don’t believe it’s electrical as when I run it directly from a portable tank to the motor it seems to run fine, when I run it directly from the built in tank to the motor it’s fine it only seems to be when I run it though the moeller that it runs bad it seems that the main engine isn’t getting fuel. I just discovered this last night. Do the actual physical moeller housings go bad? Can’t believe the shops couldn’t figure this out going to swap it out with a new one as it’s easy.

 

[kingblazer84]

I have no idea if it’s the plastic moeller you’re referring to it came with the boat. I don’t believe it’s electrical as when I run it directly from a portable tank to the motor it seems to run fine, when I run it directly from the built in tank to the motor it’s fine it only seems to be when I run it though the moeller that it runs bad it seems that the main engine isn’t getting fuel. I just discovered this last night. Do the actual physical moeller housings go bad? Can’t believe the shops couldn’t figure this out going to swap it out with a new one as it’s easy.

Swapping that housing for sure is where I would start and run and new racor filter. I wonder if it’s plugged up inside the housing with contaminated varnish or gunk even sheet from bad fuel stations..

 

[ship happens]

Is that filter housing composite material or aluminum ?

Also if you have not already removed the anti siphon valve I would do that as well

 

[Fishin]

Well if the housing was going bad you would of seen air bubbles when you did the compressed air and soapy water


Does it have one of those stem type filters in the center filter there is a 2" stem that protrudes down into the filter I know at work on a lot of machines if you don't pull that onring and change it it has issues when there is high fuel flow

When I ran the compressed air i by passed the housing... I believe the housing could be the issue.

 

[Fishin]

Is that filter housing composite material or aluminum ?

Also if you have not already removed the anti siphon valve I would do that as well

It’s plastic/composite I guess. Anti siphon valve looked good when I removed it.

 

[ship happens]

It’s plastic/composite I guess. Anti siphon valve looked good when I removed it.

We figured that out long ago and I stopped stocking those. Years later they were discontinued. The warp, leak, Crack, not UV stable. Pieces of absolute garbage

Personally I like the Sierra aluminum ones.