2004 Yamaha 115 randomly shuts off on plane

Fishin

Member
Hey guys kinda a weird one but running out of ideas now anyone ever have something similar happen? Motor starts and runs fine gets up on plane cruising around for a while at various rpms then the motor will just shut off as if the key is turned off, sometimes will restart and run fine other times not so much. Been to the shop several times plugged into the computer no fault codes showing and replaced the following.
-fuel filter
-fuel water separator
-vst screen was cleaned
-fuel pump
-put a shut off valve where it T’s off as both motors are plumbed into the same tank.
-all 4 injectors inspected &ultra sonic cleaned all in good working order
-spark plugs
- fuel tank is newer, all hoses and tank are clean.
-battery connections are good and clean
-wiring is super tidy on the boat and appears to be on the motor as well. Thinking it is an electrical issue instead of a fuel issue now.
losing motivation and getting very frustrated pouring money into this thing. Sorry for the long read lol
 

Fishin

Member
Also compression tested all 4 cylinders have good compression, nice and even at 200psi each. Motor is also a 4 stroke since I forgot to post it.
 

kingblazer84

Well-Known Member
its weird its not setting any hard codes... too bad you can replicate with a tech on board with the scan tool hooked up then get the live data and freeze frame when it conks out
 

ReelSlim

Crew Member
I had the same thing happen to my 2008 f150. Pulled my hair out checking every connection as it seemed to be an electrical issue. After lots of google time I found one last thing to try. The solution was the actual ground connection on the outboard. It seemed strange but I gave it a try. I removed the factory ground connection bolt...cleaned up what appeared to be white dust and installed it. It solved my issue for the remaining time I owned the boat. The connection seemed tight and was painted at the factory but the threads did have what I assume was some oxidation on them causing an intermittent loss of ground and would shut my motor off. I would give it a try....
 

GDW

Well-Known Member
Is it starving of fuel? There’s a little in line filter inside the engine.

I had the same thing took it to a shop they did all this work and didn’t fix the problem.

took it back mechanic took the cowl off and pulled this little piece of plastic off, tried to blow through it and said there’s your problem. Took him 5 minutes don’t know why my previous bill was over $500 for shit I didn’t need????

Anyways if your motor dies try pumping the ball if it goes again for awhile it’s certainly fuel related.
 

Grey Ghost

New Member
I have a 2004, 115, 4 stroke Yam on a Hewescraft....I had the same issue...Went through the same process.....It was the fuel pump fuse....the aluminium fuse had corroded. All new fuses and the plug ins cleaned and dielectric silicone......Runs great. Good for another 1500 hrs.
 

Fishin

Member
I have a 2004, 115, 4 stroke Yam on a Hewescraft....I had the same issue...Went through the same process.....It was the fuel pump fuse....the aluminium fuse had corroded. All new fuses and the plug ins cleaned and dielectric silicone......Runs great. Good for another 1500 hrs.
Thanks a ton! Going to look into it tonight, do you remember what kind of fuses it takes? Cheers
 

Fishin

Member
Is it starving of fuel? There’s a little in line filter inside the engine.

I had the same thing took it to a shop they did all this work and didn’t fix the problem.

took it back mechanic took the cowl off and pulled this little piece of plastic off, tried to blow through it and said there’s your problem. Took him 5 minutes don’t know why my previous bill was over $500 for shit I didn’t need????

Anyways if your motor dies try pumping the ball if it goes again for awhile it’s certainly fuel related.
Yeah definitely frustrating I’ve spent $1240 so far trying to correct this issue but the shop hasn’t quite figured it out so I’m going to try a few things on my own before sending it back for an other hefty bill lol. Yes the fuel system is all good it’s been gone over 3 times we’ve ruled it out
 

Fishin

Member
I had the same thing happen to my 2008 f150. Pulled my hair out checking every connection as it seemed to be an electrical issue. After lots of google time I found one last thing to try. The solution was the actual ground connection on the outboard. It seemed strange but I gave it a try. I removed the factory ground connection bolt...cleaned up what appeared to be white dust and installed it. It solved my issue for the remaining time I owned the boat. The connection seemed tight and was painted at the factory but the threads did have what I assume was some oxidation on them causing an intermittent loss of ground and would shut my motor off. I would give it a try....
I’ll definitely look into it thanks a ton!
 

profisher

Well-Known Member
Faulty Ignition switch (key switch either dash or remote box)
 
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Matthew S.

Member
Kill switch? Motoring on plane usually a bumpy ride. Maybe something to do with the kill switch. Over time, my plastic kill switch "key" spread apart and the motor turned off at random. Scared the crap outta me.
 

Fishin

Member
Kill switch? Motoring on plane usually a bumpy ride. Maybe something to do with the kill switch. Over time, my plastic kill switch "key" spread apart and the motor turned off at random. Scared the crap outta me.
Checked that too but it all seems good, I’ll be going for a ride with a tech and have the engine plugged into the computer I guess
 

Reel Gone

Active Member
I would check the grounds as Slim says as I have witnessed this as well. My brothers boat did the same thing, while running on plane it would just shut off. it turned out to be a ground which I believe was on the ecm. His was an inboard/outboard but could certainly be your problem
 

profisher

Well-Known Member
Ignition switches when they go can do so intermittently. I have had this a couple times. Going along and its just like someone turned the key off...the motor just dies...no sputtering. You can crank it but no fire. Then check again 5 minutes later and it fires up. The trouble is you can't confirm it 100% unless you have a meter on it when it is acting up and like most electrical gremlins it won't cooperate anytime you are ready for it...or the mechanic is. I went to a local shop and we found a used ignition switch and they were good enough to lend it to me for a few trips....the problem went away so I took it back and bought a new one from them.
 

bpsuls

Active Member
Really sounds like an electrical problem and I echo ground issues. I fixed an opposite problem on a buddies boat where it would start but not shut off. We looked all over but after some continuity checks on the binnacle cable bundle we discovered that the cable had a tiny Nick in it and the kill ground wire was exposed and corroded through. You may have a similar issue with another wire. Do a continuity check on the bundle if all the engine stuff checks out.
 

Derby

Crew Member
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..
 
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