Throttle Position Is Different With New Carburetor. Is A Modification Necessary?

PGB1

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  • / Throttle Position Is Different With New Carburetor. Is A Modification Necessary?
Hi All!

I have a Briggs & Stratton Model 09A413 Type 0202 Code 014006YA engine on a Craftsman 536.881501 snow thrower (Murray Number 881501NB 22 Inch 5 HP).
The carburetor's float bowl is shattered, so I had to purchase a replacement carburetor. This engine came with many different carburetors and this one is obsolete. The unit I purchased is said to be the aftermarket direct replacement, but there's a difference in the position of the throttle. I'm writing to ask if this is OK, or will I need to make modifications.

To Illustrate With Words:
When the engine is off & the throttle linkage disconnected, the arm from the governor is fully toward the right, closeest to the carburetor. When the engine runs, the position changes based on load upon the engine, moving farther left (away from the carburetor). The governor can open the throttle plate fully.

With the Original Carburetor: When the engine is off, the governor's arm is fully to the right side (toward carburetor) and the throttle plate is closed.
With the New Carburetor: When the engine is off, the governor's arm can't get as far right as it did with the old carburetor because the hole where the throttle linkage wire connects is
in a different location. When the engine runs, the travel of the governor will still let the throttle plate open fully, but the governor's arm won't be as far left (away from carburetor) as it
was with the original carburetor.

Will this position change matter, since the governor can still fully close & open the throttle plate?
If it does matter, what change do you suggest I make. (I understand one should never adjust the position of the governor arm on its shaft.) The plate with the hole for the throttle linkage is too small to re-drill in the old carburetor's position.

I do have a tachometer from my work that I can set the RPM if needed. The glitch there is that any engine or machine manual I've found doesn't state the RPM, so again I'm relying on your expertise for what it should be.

A photo is attached that I hope better explains the carburetor question.

Thanks Very Much for your help. It's appreciated.
Paul
 

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StarTech

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  • / Throttle Position Is Different With New Carburetor. Is A Modification Necessary?
Doing two threads on the same problem doesn't help. First the engine is 2004 since that is the date code posted in the other thread and the one is invalid as there is no month 40 in our year; unless, you are on a planet in an alternate solar system.

As the throttle position is important as if the governor is reposition a considerable amount it can get interfered with by the engine shroud or other engine part. You may be able swap out the throttle shafts provided they are the same diameter and vane position is vertically the same.

Either way working with a none matching carburetor is a gamble. As RPMs the idle spec is 1750 and max is usually around 3600.

Just note both the float and float bowl are still available for the old carburetor.
 

PGB1

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  • / Throttle Position Is Different With New Carburetor. Is A Modification Necessary?
Hello Star Tech. Thank You very much for taking time to reply with helpful information. I think your ideas have me on the way to a happy machine. Also, sorry I didn't reply sooner. I don't get notifications of replies for some reason & forgot to check here.

I apologize for making a new thread. I thought it was wise to do so since this is a whole different question, but it is same engine none the less. Sorry for the goof.

It's kind of odd about the date code. I re-checked it and what I wrote in the other thread is what's stamped: 041006YA.

Thanks for the notes about the governor position & RPM. Thankfully, the governor's arm won't hit anything if I have to leave the new carburetor as-is.

The floats I found didn't match, nor did the needles, so that swap was out. A Briggs & Stratton tech guy told me that they made several variations of the carburetor, all quite different & that is why I couldn't get a float. (Sounds like they made them at whatever off-shore factory bid lowest.)

Your idea of swapping the shafts is genius.
I got lucky: The old shaft was the larger diameter of the two, so all I had to do was turn the lower portion diameter down 2,6 mm on the lathe. Since the old shaft is now going into the new carburetor body, I put the new plate onto the old shaft, figuring the fuel was metered to match that plate. Now the throttle wire hole positions look like they will match.

Hopefully, I can get to the job in time to install and test the machine. I'll write back with the results.
Thanks Again for helping,
Paul
 
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