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superbman101

Carb Main-Jet (Nozzle) Difference?

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superbman101

Hey Guys I've always wanted to know the actual difference between:

390950 (Labeled B)(#40 Jet) Used Before Code Date 81101200

691966 (Labeled B) Used After Code Date 81101100

Could you interchange them? The only thing I've noticed are the number of holes in the main-jet. Is this because the new (1981+) have a larger sloped intake tube? Very puzzling sm00

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RayS

I think there is a length difference in the nozzel. Larry8200 had a post on this a year or two ago. So you should beable to find it in a search. I have both kits, but to cold to go out and measure.

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superbman101

I don't know if it does make a difference in pulling or not? I pull with the older short one and it seams to be fine for me. I have a 91 16hp I/c that's really got a touchy throttle. I'd go with the newer of the two if you have one because parts will be easy to get ahold of years from now

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dynodave
Originally posted by superbman101

I've been digging around yes the length is the difference.390950 (OLDER) 2.534" EARLY "40"id="red">691966 (NEWER) 2.749" LATE "B"id="red">both are same size holes (4 of them) .... my observation is 3/4 id="red">Thanks Ray :P

....My observation shows 3 fuel delivery holes in one and 4 in the other. The air bleed holes seem to be the same but I will have to measure them again to refresh my memory. No disagreement with length difference.

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