Yamaha 90 sudden power loss then powers up again.

[Sea lyin’]

Brothers boat, he’s got a 2014 90yamaha. Runs great except twice now at wide open throttle it has suddenly bogged down and slowed down to about double trolling speed but not quit. Then without touching anything it picked up speed again and continued on the rest of the journey with no problem. One trip was about 3 miles after it happened and the other was about 10 miles with no problem. And about 3 months use between the two incidents. It’s in storage now but he’ll be taking it to get scanned come spring. Til then anybody have any ideas?

 

[kingblazer84]

Brothers boat, he’s got a 2014 90yamaha. Runs great except twice now at wide open throttle it has suddenly bogged down and slowed down to about double trolling speed but not quit. Then without touching anything it picked up speed again and continued on the rest of the journey with no problem. One trip was about 3 miles after it happened and the other was about 10 miles with no problem. And about 3 months use between the two incidents. It’s in storage now but he’ll be taking it to get scanned come spring. Til then anybody have any ideas?

Maybe the fuel pump is sucking air? Injector getting stuck open flooding out a cyl? Hard to say without codes or seeing it first hand

 

[Sea lyin’]

Maybe the fuel pump is sucking air? Injector getting stuck open flooding out a cyl? Hard to say without codes or seeing it first hand

I told him same thing. Sounds to me like sucking air but he’s hoping a forum member might’ve had the same issues and can give him a heads up. I told him it’s all sensors and fuel injectors so best to have Kelowna Yamaha run a scan rather than throw money at it.

 

[ab1752]

Check the main ground on the side of the block My buddys 150 yamaha 4 stroke was doing exactly the he same and after he went through everything else, I showed up and said hey why is this so loose. Haha fixed for free!

Is sounds like spark to me since it is coming right back to fire. Fuel would stumble longer and take a bit to fire up again I figure. Good luck l.

 

[hippaisland]

Getting any alarms?(beep codes)

 

[Stizzla]

It was the racor fuel filter on a buddy’s boat that caused a similar thing.

 

[profisher]

Fuel pumps can vapour lock when the fuel gets hot enough. Wide open throttle would create the highest normal temp under the engine cowling. If it was running a bit warmer than normal (but not enough to trigger an alarm) it might put it past that vapour lock threshhold. Does that model have a fuel pump with water cooling it? Many do for this reason.

 

[N2013]

Brothers boat, he’s got a 2014 90yamaha. Runs great except twice now at wide open throttle it has suddenly bogged down and slowed down to about double trolling speed but not quit. Then without touching anything it picked up speed again and continued on the rest of the journey with no problem. One trip was about 3 miles after it happened and the other was about 10 miles with no problem. And about 3 months use between the two incidents. It’s in storage now but he’ll be taking it to get scanned come spring. Til then anybody have any ideas?

I did some re-rigging last spring with my F115 and it turned out the fuel line was kinked a bit inside the rigging tube. Exact same issue. My fuel consumption gauge was way off as well. Check the lines and work your way back to the mo-mo. Definitely fuel issue.

 

[Sea lyin’]

Getting any alarms?(beep codes)

No, he says he’s not getting any alarms.

 

[Sea lyin’]

It was the racor fuel filter on a buddy’s boat that caused a similar thing.

Thanks, I’ll have him take look and see.

 

[Sea lyin’]

Fuel pumps can vapour lock when the fuel gets hot enough. Wide open throttle would create the highest normal temp under the engine cowling. If it was running a bit warmer than normal (but not enough to trigger an alarm) it might put it past that vapour lock threshhold. Does that model have a fuel pump with water cooling it? Many do for this reason.

Hmm, interesting. Im not sure but I remember looking at it and thought it was sure a different looking fuel pump. If it actually was the fuel pump. Lol. Whatever I looked at had three hoses coming off it and was a flat rectangle on the right rear lower side of the engine. I’ll go see him tomorrow and see if I can get another look

 

[Sea lyin’]

I did some re-rigging last spring with my F115 and it turned out the fuel line was kinked a bit inside the rigging tube. Exact same issue. My fuel consumption gauge was way off as well. Check the lines and work your way back to the mo-mo. Definitely fuel issue.

Thanks for the info. Going to see him this weekend and will work our way through this list and see if there’s anything obvious. After that, have to wait til we can get on the lake and run it til it happens again or not.

 

[T H]

One more thing to check would be your anti-siphon valve connected to the fuel pickup tube. The little ball and spring in there can corrode and stick introducing air into the system. $20 part you can get at any Marine store. If you're not getting water in the raycor or any obvious restriction, it'll likely be that.

 

[ship happens]

You can just knock out the ball and spring with a punch. Do not put a brass fitting into the aluminum tank!

 

[ship happens]

If it was fuel restriction it could possibly do that, however not likely. If it was a bad low or high pump it would die, not keep running. I would say its loosing a cylinder. Either an injector, plug or wire. I've seen all three what I just mentioned on the yammy stuff

 

[Fishtank]

Exactly the same thing happened to me but on a suzuki df200, turned out to be one of the gas filters on the engine, I replaced the the large clear filter and also the high pressure filter but it turned out to be a tiny little filter that connects to the vst. So moral of my story is I would start with the fuel filters because they need to be replaced at some point anyways

 

[Fishtank]

If it was fuel restriction it could possibly do that, however not likely. If it was a bad low or high pump it would die, not keep running. I would say its loosing a cylinder. Either an injector, plug or wire. I've seen all three what I just mentioned on the yammy stuff

Mine kept on running when it was a bad filter, I would loose rpm while cruising and if I restarted the engine I could get back up to the higher rpm before bogging down

 

[sasqman]

Sounds very similar to an issue I had with my merc. Full throttle, then drop down to just above idle out of no where. I would shut off, restart and all was good again until the next time. Mine ended up being the filter in the fuel bowl assembly. Could be this part. These should be changed every 500 hours.

 

[ship happens]

It's amazing how filters get clogged even after a 10 micron filter.

 

[Trophy]

Similar issue with a old 150 black max several years ago. After many attemps by marine mechanic to identify it was a stator issue, $$$ later. Hope yours isn’t heading in that direction.