This weekend running the boat all day, it suddenly slowed down. When I increased the throttle it acted as if I was jerking the throttle back and forth. about 2 minutes later, it started running fine. Ran fine for hours. Later that night the wife and I were out and it did it again. I could not get over 900 RPM’s. called seatow as we were in the middle of the lake and getting nowhere fast.
Next morning, it ran fine.
Any thoughts? I’m think the fuel pump might be going bad
Similar experience on First Born’s boat a couple years ago, same engine. If i recall it was something to do with the fuel/water separator. I’m sure if you PM him he can give you some better details.
Good luck, broke boats suck.
quote:
Originally posted by Bolbie…the harbor was slick as an eel pecker.
Seems like all of these 115’s have similar problems at some point. From what I’ve read and experienced with my own 115 is that you need to have the VST filter changed and perhaps the injectors cleaned. Also check for any air leaks in hose lines. There are DIY videos on VST if you are handy but I’m sure Chris V or one of the other yammie dealers can do it in there sleep
I have read online alot about the VST. Unfortunately the boat is in Lake Murray and I’m in Charleston. And without a trailer, doing work while it is in the water is very tough.
Also check the anti-siphon valve at the gas tank side of the fuel line going to the motor. The ball in the valve can get stuck at times.
anti-siphon valve? Thats a new on for me. Can you tel me more about it?
I just sold my boat last Friday that had a 2001 Yamaha 115 4-stroke.
Mine started having fuel issues last year. I started with water/fuel separator, then the little filter in that cup like container on the back of the motor and then then had the fuel injectors redone. While they were out, I pulled the VST tank out and opened it. The electric fuel pump is in that tank. Down on the bottom of that pump pick-up is a little screen filter about as big as a nickel.It was clogged up with tiny bits of trash and there was more trash like that down in the VST tank. No sign of water in the fuel. Anyway, I put it all back together and it seemed OK. Also check you primer bulb. They can go bad after a few years and cause problems. I’d try the easy things first like primer bulb, check valve and fuel filter on the engine. If none of those fix the problem, then it’s probably good to have the injectors and the VST checked as well.
Jack Taylor
I had that issue with my 225 4 stroke. had to clean that screen. But it acted differently. When the 225 was clogged it simply bogged down when I gave it gas.
The 115 “pulses” as if it gets fuel, then no fuel, then it gets fuel, then no fuel.
I had similar issues with an F150. I changed the onboard water separator/fuel filter, the filter element in the engine mounted water separator/fuel filter, the VST filter, and an inline fuel filter that is located just before the VST. Engine ran fine afterword’s. If I had to pick the actual culprit, I would say the problem was caused by the filter element in the engine mounted separator/filter. I couldn’t blow through it. The other filters had some air resistance but were not “stopped up”.
Hope this helps
ZX
Had a similar issue with my 2002 Yamaha 115 4stroke…ended up having to have all filters and fuel injectors replaced. While at the mechanic, there were 2 other Yammy 115’s with the same issue. Appears to be common issue.
Thank for the info.
Waiting on a mobile mechanic now…
It feels like if you kink the fuel hose, let go, then kinked it again…over and over. The motor shakes violently.
quote:
Originally posted by Fishb8It feels like if you kink the fuel hose, let go, then kinked it again…over and over. The motor shakes violently.
How old is it by the way? I have a 2014 115 Yammie.
I think it is an 06.
Anti-siphon valve is typically located on top of teh fueld tank where the fuel line comes out of the tank.
http://www.louisianasportsman.com/details.php?id=1271
It has a ball inside that only allows fuel to go one way, to prevent fire from travelling back into the tank from the gas line. I had one stik on me like that. Run fine sometimes & then ran like you described for no reason. Finally tracked it down to being that. Had it replaced & no more problems.
mine looked very similar to this but was brass.
http://www.iboats.com/Anti-Siphon-Valve-3-8-Barb-3-8-NPT-Moeller/dm/view_id.392107
Something else to keep in my head.
Mechanic says it is most likely the vst filter. Going to have the whole fuel system gone through and injectors cleaned.
I hate when I know I can do something but have to pay to have it done.(with exception to the injectors, don’t know how to do them). No trailer and very limit tools and time make it a tough decision. But no reason having a broke boat sit in the water.
I had the same problem on a 2004 model. I fought it for two years and then finally broke down and changed ALL of the fuel lines, cleaned the VST, replaced the VST filter, drained the old fuel, and cleaned out the tank before refueling and running with non-ethanol gas. The boat ran better than it had in years! The thing about “fuel problems” is that there multiple ways to “band aid” the issue (ie cleaning injectors or VST) but if your non getting to the bottom of it and finding the source, you can easily find yourself wasting a lot of time and money cleaning injectors, VST’s, and adding unnecessary filters(which I did at one point). Bottom line is that I would do all in one big swoop so that you dont find yourself fighting it again. Thats only my 2 cents but I hope you get it figured out soon. Looks like we might get a couple nice days to play this weekend!
PS: i hav an extra set of refurbished OEM injectors for a yamaha 115 with all of the seals/rubbers if you know anyone that wants/needs them. I sold that boat last month.
My response was intended to assume that the fuel rail pressure, VST pump, and rail fuel rail valve had been verified and that you are certain it is not an IAC problem or something that can cause similar issues. I hope this helps
Thanks Trey,
They picked the boat up Tuesday and returned it Wednesday. My brother is at the lake but was not home when they returned it. He said it runs fine now. I have no idea what was done nor what it cost yet. I do know that the guy that cleans injectors was there on Wednesday.
When my brother called to find out what was done and the cost, the lady said she would get back to him, because the mechanic is very busy right now. No matter what, can’t beat 1 day turn around that includes picking it up and returning it (it has no trailer)