72 Cheetah 399 carb adjust ? - Snowmobile Forum: Your #1 Snowmobile Forum

marlli53 · 12-08-2006, 04:48 AM

This sled starts, idles and runs good at low rpm but boggs badly when throttle is opened more than half way. It has a Walbro wda carb, is the high speed screw on the left side lower portion of the carb body? What is the adjustment screw on top? Thanks.

**RJ Gleason** · 12-08-2006, 05:05 AM

The one on top is the Main Fuel needle.
Both adjusters are started at 1 1/4 turns out from gently bottomed. Then adjust in 1/4 turn increments as needed.

marlli53 · 12-09-2006, 04:05 AM

Thanks, but what is the screw on the side down low? The top screw doesn't seem to have a lot of effect on the high speed power. Thanks again..

**smallengineguy** · 12-09-2006, 08:47 AM

That's the low speed. If it's OK there, don't adjust that one. If the top screw doesn't do anything, a rebuild may be needed.

**RJ Gleason** · 12-09-2006, 11:21 AM

A cleaning too.
A full dip cleaning is best.

marlli53 · 12-11-2006, 06:27 PM

Thanks again. I guess I'll have to do the rebuild, adjusting the low sped screw did wonders but the screw refuses to stay put. I could also use an exploded drawing of the WDA-1 carb, anybody know where I can pull one up on line?? Thanks

brideauj · 12-11-2006, 06:41 PM

I have some generic WDA documents in PDF. Send me your email by PM and i'll send them to you.

marlli53 · 12-12-2006, 04:56 AM

mark_allred@msn.com

brideauj · 12-12-2006, 10:57 AM

smallengineguy put the link in the engine/transmission forum under the stikey for "how-to"

**RJ Gleason** · 12-12-2006, 03:43 PM

http://www.snowmobileforum.com/engin...html#post48900

marlli53 · 12-13-2006, 04:47 AM

You guys are the best!! I disassembled the old Walbro and found the threads on both low and high speed screws were worn badly, I have an extra carb so I switched the main body and screws, new gaskets etc. and woopie she runs like a new sled. Thanks mmucho for all the help. M

**RJ Gleason** · 12-13-2006, 10:22 AM

Another satisfied SF.com customer

:O