Farm Equipment - D15 Carb

D15 Carb

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=207183
Printed Date: 25 Jun 2025 at 10:28pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: D15 Carb

Posted By: modirt
Subject: D15 Carb
Date Posted: 21 Jun 2025 at 4:51pm

Was raking hay the other day and engine started surging, then wanted to die. Suspected it might be the carb, so hopped off and turned rich/lean adjustment screw out and after about half a turn, she smoothed out and ran fine after that.

Trouble is that screw is almost loose enough to be floppy and problem may have developed by screwing itself in. Tried to tighten the smaller of the two nuts and it is more or less as far down as it is going. Does that have some form of packing in there that can be or needs to be replaced? Or......how does one firm that screw up so setting doesn't wander?

I assume for best fuel economy for light duty use like raking hay, one wants it running as lean as it can? Right now it is about 3 turns out.

Replies:

Posted By: steve(ill)
Date Posted: 21 Jun 2025 at 6:11pm

3 turns out is normally i little excessive.. It might mean you have a little piece of crap plugging a jet inside.. I have wrapped teflon tape on the threads to tighten things up somewhat.. a coil spring under the screw head can also help... if it has a head on it..

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

Posted By: Kenny L.
Date Posted: 21 Jun 2025 at 6:26pm

Modirt, Text me your address and I will send you something that will fix you right up it's off of the packing that was use on the water discharge pump on the wash plant that I run at one time. I did have your address but miss place like a lot of stuff around here. I text you. Kenny Loughren.

Posted By: modirt
Date Posted: 24 Jun 2025 at 2:17pm

Was raking hay yesterday and tractor started to act up. Lost most power then began to sputter. Got the rake off, then limped 100 yards or so up the road to neighbor's shop. Told him about the carb (jet screw was now spinning freely and had play in it) so he pulled the jet, (gas leaked out which may have back flushed and crud out), then put a wrap or two of Teflon tape on it for packing and back in she went. She started and after screwing in the jet till the rpm's started dropping off.......we backed it out about 1/4 to 1/2 turn and she smoothed right out. Ran it for an hour today pulling a hay tedder and she never missed a lick. Back from the dead.

Always amazes me how badly off a perfect running tractor can get if the carb is off by even just a little. Lots of critical links but that one has to be close to the top of the list of potential troublemakers. Diesel pump and injectors far more reliable.

Posted By: DSeries4
Date Posted: 24 Jun 2025 at 3:43pm

Might want to clean out your tank and replace the screen in the sediment bowl while you are at it.

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'49 G, '54 WD45, '55 CA, '56 WD45D, '57 WD45, '58 D14, '59 D14, '60 D14, '61 D15D, '66 D15II, '66 D21II, '67 D17IV, '67 D17IVD, '67 190XTD, '73 620, '76 185, '77 175, '84 8030, '85 6080

Posted By: modirt
Date Posted: 24 Jun 2025 at 6:13pm

Tank is clean. No crud.....no water, no rust. New sediment bowl, with new screen. As of today, running like it should. Love listening to that little engine work.