My Willys 3A and 3B Community

3A, 3B, DJ Technical Knowledge Base => "Original"-- Technical Questions, Answers, Observations => Topic started by: Spacecrab on January 17, 2021, 07:27:26 AM

Title: Choke Disc
Post by: Spacecrab on January 17, 2021, 07:27:26 AM
Hi guys,

While climbing uphill my 3b suddenly coughed and spluttered to a halt

It seemed to start up but die as soon as I accelerated, after taking off the hose to the carb I realised the choke disc was missing!

While I found it vibrating around inside the carb: it's two screws are completely gone

Should I be worried where those went? I opened the lower portion of the carb but found no sign of them. Could they be bouncing around causing havoc somewhere?

Also no other screws seem to enter, the carb is a YS950s I took from an M38a1, I tried the choke screws from a damaged YF938 and various machinery carbs but to no avail.

While I have a kit coming I'm not convinced it has those two types, the hole seems to taper in

Has anyone had to come up with another solution to attach a choke disc?

Any advice welcome, thanks
Title: Re: Choke Disc
Post by: SteveKfl on January 17, 2021, 08:59:47 AM
If it were mine, and since you mentioned you were "going up hill", indicating off level ground, I wouldn't chance those screws making their way passed the intake manifold to the valves and pistons.  I'd pull the intake off and look inside it, and in the ports as well.  It's easier to 'find the screws', then to find pistons and all that goes with replacing one.  Good Luck!
Title: Re: Choke Disc
Post by: BillT on January 17, 2021, 09:20:25 AM
As far as identifying the correct screws for the choke plate check with Scout over on the olejeepcarbs.com site. He would have the answer. I would be concerned about the screws rolling around loose also.
Title: Re: Choke Disc
Post by: Rus Curtis on January 17, 2021, 10:44:18 AM
Being a 3B, I'll assume an F-head engine.  The intake manifold is inside the head.  So to find the screws (hopefully they found a resting spot somewhere in the intake before the cylinders), the head will need removing.  If they found their way into the cylinder, then with the head removed, you'll be able to see.

(https://cj3b.info/Photos/Parts/EngineFront.gif)
Title: Re: Choke Disc
Post by: scoutpilot on January 17, 2021, 11:43:40 AM
The screws are brass, but can still cause damage. I would make sure the holes in the shaft for the screws aren't wallowed out. If not too bad, thread lock should hold the screws. If you have any trouble finding replacement screws let me know.
Title: Re: Choke Disc
Post by: Spacecrab on January 19, 2021, 05:44:50 AM
Thanks so much guys,

Really appreciate the help: yes it's an F Head Rus, I really hope they are resting somewhere too.

@scoutpilot: I'll let you now if the carb kit doesn't come with the screws, I'm not so hot on tapping something so small to use conventional screws. I'm just surprised the choke screws for the YF didn't fit: I figured same company and the carbs were at most made within a few years of each other for the same engine. Hope the threads aren't damaged

I'll get the head pulled and see if they are there. thanks again