38 mm Mikuni Round slide Carbs - Snowmobile Forum: Your #1 Snowmobile Forum

DonColliau · 12-19-2005, 01:18 PM

I messed up when I took the carbs off and didnt label which side went where. The carbs dont have any numbers on them either. I did notice that the throttle cables are 2 different lengths. I assume the longer one would go to the PTo side of the motor. When I removed the carbs I just unscrewed the slides out of the top and didnt remove them from the cables. I have read that there is a different size jet for each side but I am not sure which is which. any help would be greatly appreciated as I have searched all over looking for some info

Thanks, Don

this is on a 96 494 lc s-chassis

upersleder · 12-19-2005, 01:45 PM

your going to have to look at the main jet size, it is written on the jet, the larger one (bigger number) goes on the PTO side

DonColliau · 12-19-2005, 02:45 PM

ok, here is what i found out. My old motor, a 96 has the same size jet listed for both carbs they were the same carb. the new motor is a 99 and that does have 2 different jet sizes. my question is this, will my carbs off of the 96 engine work ok? it is the same exact motor just 3 years older. I just want to make sure i wont burn up.

specs.

96
2 vm38-311 carbs
2 mj-320 main jets

99
1 vm38-412 carb
1 rvm38 -413 carb
1 mj 300 main jet
1 mj280 mian jet.

again, i dont have the 99 carbs, i have the 96's. will they work ok?

**smallengineguy** · 12-19-2005, 03:00 PM

They will be richer, so no need to worry about running too lean, but you may have to jet leaner if you start fouling plugs.

DonColliau · 12-19-2005, 03:02 PM

and to jet leaner would be to go with a 300 over a 320? or should i rejet with the jets they used in the 99?

upersleder · 12-19-2005, 03:29 PM

you could try it if its running way rich. just be sure to not get it too lean.

letitsnow · 12-19-2005, 05:27 PM

why do they have different jets for different sides of the motor?

**smallengineguy** · 12-19-2005, 05:35 PM

One side runs hotter than the other, usually the PTO side
(clutch heat, etc.) A little more fuel will keep that side cooler.