Yamaha 130 v4 idle mix screws

[maineiac5586]

My 2001 130 v4 loads up when running at a fast idle say 1100 to 1500 rpm range. It doesn't stall but you can tell it's not as smooth as it should be. I set the screws to factory spec bur may need some finite adjustments? On my last 115 v4 I remember not noticing a perceived change when adjusting each of the 4 screws. How do you guys set these? I'm assuming running in a barrel won't be good enough especially considering if I am in forward at that speed it'll be throwing the water out of the barrel.

 

[jimmbo]

Two Strokes do tend to Load up at Lower Speeds, Nature of the Beast, but an Overly Rich Mixture will certainly speed that up.
Factory Spec? There is an Initial Setting, that will allow the Engine to run, a bit on the Rich Side.
The final Setting must be done with the Engine Warm and under Load. There are a variety of ways that are used, and everyone will swear theirs' is the Only Way.
My way was to have the boat in the Water, in gear, either puttering around, or have the Stern tied to a very Heavy Anchor, or a solid Dock. I would start with the Initial Settings, and Lean each Carb, individually, Rpms will go up. When the Rpms start to drop, I would make a Note as to who far in I turned it, return it to the Initial Setting, and move on to the next Carb. After I had done that to all, I would then compare the Responses which I had noted. I would then turn each respectively 3/4 way between the Initial Setting and the Lean Stumble. Then I would run the motor at the speced Idle and repeat the Process, but this Time, adjust for the highest rpm, and then returning to the Speced Rpm, Repeat for the other Carbs, then go thru it a couple more times. After, check Acceleration, if it Bogs, open all Mix screws up an 1/16 turn

 

[maineiac5586]

Two Strokes do tend to Load up at Lower Speeds, Nature of the Beast, but an Overly Rich Mixture will certainly speed that up.
Factory Spec? There is an Initial Setting, that will allow the Engine to run, a bit on the Rich Side.
The final Setting must be done with the Engine Warm and under Load. There are a variety of ways that are used, and everyone will swear theirs' is the Only Way.
My way was to have the boat in the Water, in gear, either puttering around, or have the Stern tied to a very Heavy Anchor, or a solid Dock. I would start with the Initial Settings, and Lean each Carb, individually, Rpms will go up. When the Rpms start to drop, I would make a Note as to who far in I turned it, return it to the Initial Setting, and move on to the next Carb. After I had done that to all, I would then compare the Responses which I had noted. I would then turn each respectively 3/4 way between the Initial Setting and the Lean Stumble. Then I would run the motor at the speced Idle and repeat the Process, but this Time, adjust for the highest rpm, and then returning to the Speced Rpm, Repeat for the other Carbs, then go thru it a couple more times. After, check Acceleration, if it Bogs, open all Mix screws up an 1/16 turn

Wow. Very thorough. Thank you

 

[Doh]

The Idle Air Screws on a 130 V4 are Air, not Fuel, so they work backwards, turning them out Leans the Mixture, in Richens it.

Start all 4 a 1&1/2 turns out and adjust from there. My 130 was very cold blooded

 

[boscoe99]

The Idle Air Screws on a 130 V4 are Air, not Fuel, so they work backwards, turning them out Leans the Mixture, in Richens it.

Start all 4 a 1&1/2 turns out and adjust from there. My 130 was very cold blooded

How did you come to this conclusion?

 

[99yam40]

that is news to me also.
I believe the idle air jet and fuel jets are not adjustable.
the screws allow you to adjust how much of that combination to let thru

 

[Doh]

How did you come to this conclusion?

Try it and find out for yourself. Turn in-enrishens, turn out-leans. 20 years of running a V4 130 Yamaha.

That is why the "Air" is in the Explanation of the Jet. Otherwise it would just be called "Idle Jet" or "Pilot Jet"

 

[boscoe99]

Yamaha's term for an idle mixture jet is "screw, air adjusting".

It does allow some air in as the screw is turned outward. Air that is mixed with gasoline. As the increased air and gasoline mixture gets into the combustion chamber it results in a richer fuel/air mixture.

 

[jimmbo]

An adjustable Air Bleed is all it is. It is unlike an Idle Speed Control, though I'm sure it has been misadjusted to achieve that Purpose

 

[boscoe99]

Here is what Yamaha has to say


img uploads

 

[99yam40]

seems some people think the Yam130 is special/different from all other motors Yamaha and others make

 

[jimmbo]

So Yammie, because they couldn't get a Carb with Air Holes in the Throttle Plate, have created a way of really getting an Engine, especially a Multi Carbed one, difficult to tune.
More Proof that the Proper Service Manual is Needed, and NEEDS to be read, as I have never seen a Carb on a 2 stroke, that had an adjustable Idle Stop. Of course, I have Never seen a Yammie with its Cowl off and Carbs exposed(not many in this Neck of the Great White North). Maybe if I had, I would have been scratching my head, and muttering WTF...

 

[maineiac5586]

So is it confirmed turning the screw counter clockwise makes it leaner? Turning them in (clockwise) makes it richer?

 

[99yam40]

no

 

[boscoe99]

Yamaha, as far as I know, does not make carburetors. Keihin or Mikuni does.