Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

[bowman316]

I have a 2007, Yamaha 8 HP high thrust motor. Last year the motor ran ok, but it was real stally. When you had it down near idle speed, it wanted to stall out. It got to be hard to idle down enough to shift to reverse, without stalling the engine.

I took the carb off to clean it, but now I am wondering if there is an air-fuel adjustment screw on there. I see no screws at all on the outside of the carb, except the one at the bottom of the fuel bowl, to drain it.
And there are 3 screws holding a plate on the top, that lets you get into the interrior of the carb.

Are the only ajustments for this carb where the linkage hooks up to it? (The throttle and choke linkage)
If I take the fuel bowl off, there are a few brass nuts screwed into where it sucks the fuel up out of the bowl. Are those the air fuel adjustment screws?

Because, when the carb is assemeled, there are no adjustment screws accessable. NOTHING

 

[Don S]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

Yes, there is. You have to drill out the brass BB that blocks access to it.

 

[bowman316]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

ok, i know exactly where that is. So you have to drill it out? like destroy the BB?

 

[Don S]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

ok, i know exactly where that is. So you have to drill it out? like destroy the BB?

It's only there to prevent people from tampering with the adjustment.

Just don't go through too fast and destroy the adjusting screw with the drill bit.

 

[robert graham]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

I believe the method is to drill a small hole in the plug and thread in a small screw enough to provide a "pulling handle"...then pull it out!

 

[bowman316]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

why would the do that? seems dumb to make people go thru all of that just to adjust a carb. Isn't that something your supposed to do an a fairly regular basis? adjust the air fuel mix?

 

[lakensea]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

Three little letters - E.P.A.

 

[99yam40]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

you should never have to adjust it unless major changes in altitude or something plugs up, and then you need to take it apart and clean it properly.
This is usually done be a person that knows what they are doing and will set it back to meet the EPA standards

 

[bowman316]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

I don't know if it needs adjusted, I just know that the engine was real stally last year. It liked to die at low throttle levels.

might just need a cleaning.

 

[fritzmerde]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

Hey just wondering if you drilled out the BB, & how it worked for you? We had to do it on my buddies 09 Honda 9.9. I was buzzing around Turkey Point last evening-a bit rough but it's good to be back on the water, take it easy

 

[bowman316]

Re: Is there an air-fuel adjustment for 2007 Yamaha 8 HP motor?

yea, i ended up drilling it out. It came out real easy. It was kinda just like a wood plug to cover up a screw hole, but metal.

It didn't really fix the stalling issue thou. I think the carbs are just still dirty.

Like it runs fine at a low idle, but dies when you kick it into gear, unless you rev it up a bunch.

even in neutral, it will run at idle, but die if you rev it up just a little, and don't rev it up a bunch real quick.