Any ideas?

[Scott yellowdog]

Was heading back in last week and at WOT it started to cut out. I opened the gas tank cap a little thinking it needed to vent. Vent on this tank is temperamental. Nope. Runs great at idle up to 1/4 throttle then it cuts out. Doesn’t die just bucks all over. Sure seems fuel related to me. Replaced the tank, new fuel line and primer bulb from tank to outboard connection. New gas. Fuel filter looks good. Briefly took it out and same. Starts right up, idles perfect, slowly throttle up to 1/4 it’s fine. Anything past that and starts cutting out. Tried squeezing the primer bulb while accelerating and same cutting out. Fuel lines look good, although they sure are wedged in there with seemingly tight turns. Unbent the lines while running and same deal.

2019 Yamaha F25 EFI

It’s been flawless until now

Thanks for any help

Dude if it's a four stroke it's water ethanal .I've just paid 700.00 to fix and get this it was under warranty it's crap I'm for clean streams an all but outboards and ethanal are a huge issue Bad Yamaha bad Mercury bad 4 strokes imagine nationwide the cost to keep a four stroke alive I bet it eventually gets everybody.s wallet I'm older and I wish I could buy 2 strokes again

 

[A-A-Ron]

My guess is crank position sensor. Its bad. As the motor spools up, its loosing ignition timing advance because it doesnt know where the crank is. 100% guess. Dont even know if it has a crank sensor lol

 

[Captain Camo]

Yes. I think you were right. Honestly when you typed that it was a foreign language to me. I should have looked it up. In the shop now. Hoping to get it back for the last few days of the season.

We all would like to know what the mechanic find was the problem with your motor?

 

[Meathead2]

We all would like to know what the mechanic find was the problem with your motor?

I'm with Captain Camo.

 

[Sweatliner]

Still in the shop. Picked it up at closing last Friday. They had said VST. Got it home and put the muffs on it in the driveway just to check. Same exact issue. Was not happy. Dropped it back off Monday morning. Have one unreturned call so far.

 

[Sweatliner]

It was the VST. Picked it up today. They said it ran fine when they checked it out when I returned it. Spent 20 minutes on the Bay before I left to make sure all was good.

 

[creedsduckman]

It was the VST. Picked it up today. They said it ran fine when they checked it out when I returned it. Spent 20 minutes on the Bay before I left to make sure all was good.

View attachment 375481

FWIW I was told to replace my fuel line every other year.

 

[metalworx]

It was the VST. Picked it up today. They said it ran fine when they checked it out when I returned it. Spent 20 minutes on the Bay before I left to make sure all was good.

View attachment 375481

Good to know, picked up one of these in November. Like the motor, but was disappointed in how loud it is compared to my f70

 

[Sweatliner]

Good to know, picked up one of these in November. Like the motor, but was disappointed in how loud it is compared to my f70

Huh. I think the motor is super quiet compared to my two strokes I’ve had. I wear ear muffs to try to save what hearing I have left though.

 

[Fogie]

FWIW I was told to replace my fuel line every other year.

My Suzuki factory line lasted a year before it got all puffed and delaminated. Replaced it with one I made out of automotive, all fuel safe line using the existing fittings and good for a few so far. Nobody made a line for it besides factory and those are $$$.