[Duck94]

I need some help if possible. I have a 86 Yamaha 25 outboard 2 stroke. It cranks fine runs great but when I go to plane it out it bogs and run about 8-10 miles an hour and won’t plane. Doesn’t die just keeps running but won’t plane. I’ve put new plugs and wires I’ve put a fuel pump on it. I tried putting a electric fuel pump on didn’t make a difference. Put new bulb and line from tank to motor.

Any other recommendations? Or anyone have this same problem?

 

[fullcredit]

Did you empty the fuel tank?

 

[Duck94]

Yes I have cleaned the carb as well.

 

[rohish]

I had the same issue and it was fuel related. Mine turned out to be a fuel line clamp failed and it was sucking air in the line at wide open throttle.
Here are some things to look at:
Run the boat at wide open throttle until it stalls. Check the bulb and see if it is collapsed. If it is, you have restricted fuel flow from your tank or a bad bulb. If the bulb looks normal, then give it a squeeze or two. It should be firm. If it is not and you pump fuel to the carb, that means your carb is starving for fuel. Then you have to look at your fuel supply from the carb back to the tank. Fuel pump, fuel lines, & fuel fittings if that's the case. It could be a restriction for fuel or sucking air in the fuel line between the tank and the carb.

 

[Duck94]

I tried squeezing the bulb while full throttle today and didn’t make a difference it’s a brand new line and bulb from the tank to the motor.

 

[Duck94]

If I sit out in the middle of the lake kill the motor for it back up and give it full throttle it will take off real quick like it supposed to for less than a second then back to bogging. I’m very confused and frustrated with it idk what to do next.

 

[BuckSnort8896]

Does it make a grinding noise when it starts to bog down??

 

[Duck94]

No it don’t

 

[Duck94]

It has good compression in both cylinders. I took it to a shop and they didn’t hardly look at it and said it needs rebuilt because it has already been rebuilt by someone and the shop said they didn’t put it together right. I wanted to get a second opinion and see if anybody else agreed with that. I wondered if the shop just didn’t want to mess with an old motor like mine. They said it’s not sealing properly. Idk much about these motors and wanted a second opinion.

 

[BuckSnort8896]

I do small engine work on the side and work on outboards often. Where are you located?

 

[mk1848]

Rebuild the carb first.

 

[BuckSnort8896]

Have you checked the fuel line? If fuel line is old and cracked and sucks least bit of air it can cause this too. Another thing would be water in the fuel which isnt super common. If your running it and just before going full throttle with it you pull the choke does it go to wot and run fine?

 

[Duck94]

I’m in benton I’m willing to let you check it out. If I pull the choke it wants to die. It’s brand new fuel don’t think it’s water.

 

[gundogs]

I had one once that did that and my fuel line was collapsing. Wasn't evident to the naked eye, but the inner wall of the fuel line would collapse and pull in, then open back up when suction was removed.

 

[Duck94]

I may try to put new fuel line on the inside and see if it helps.

 

[Duck94]

Like from the fuel pump to motor. It runs great just under a load is when it bogs.

 

[orangefeetdown]

Which fuel line did you buy? The new ones are bad about breaking down with ethanol and restricting fuel flow.

 

[Duck94]

I just bought a new one today and it did the same thing as the old one.

 

[Django]

Gotta be your high speed jet in your carb. Soak them suckers or order a new car system. Don’t take much to clog it, and if they weren’t patient and soaked it could still be clogged and hog speed jet ain’t allowing fuel. Gotta be if runs and idles fine.

 

[BuckSnort8896]

I'm in trumann it would be weekend before I could get to you to get it. I'd be glad to take a look. PM me and I'll give you my cell