Farm Equipment - What makes a WD pop when throttle is closed?

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What makes a WD pop when throttle is closed?

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=210398
Printed Date: 15 Mar 2026 at 1:22pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: What makes a WD pop when throttle is closed?

Posted By: kevin LA-CA
Subject: What makes a WD pop when throttle is closed?
Date Posted: 14 Mar 2026 at 8:39pm

I know that the WDs always pop when you close the throttle quickly. Mine really pops. Loud - 2 or 3 bangs.

Magneto ignition. I have timed by ear - don't have a timing light. Also aftermarket marvel carb with adjustable main jet.

If I got found a light, where is the timing mark?

Replies:

Posted By: steve(ill)
Date Posted: 14 Mar 2026 at 9:01pm

you dont need a light.. You can static time it at TDC on #1 cylinder.... When started, the MAG impulse will change that to the FIRE mark..

i think your timing mark is the set screw on the front pulley, pointed straight down... but others will confirm.

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Like them all, but love the "B"s.

Posted By: SteveM C/IL
Date Posted: 14 Mar 2026 at 10:45pm

Mostly the idle jet setting I think. POP BOOM POP! Yep they are great!

Posted By: sparky
Date Posted: 15 Mar 2026 at 1:20pm

To me sounds like it’s tuned correctly.

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It's the color tractor my grandpa had!