Wed Sep 26, 2007 6:39 am


I checked several online sources for the part number that Rick provided. If you've got a CaseIH dealer nearby, you could check with them to be sure. If you don't have a nearby dealer, call Ken Updike at Carter & Gruenewald, 608.455.2411.

Wed Sep 26, 2007 6:39 am

I wonder if the whole carb is an R91 with the throttle cage and choke cage milled different sizes?

I'd have to go back and look closely at all the parts manuals to compare the numbers, and try to follow the changes.

I believe your carb is all original and was made to use different seals & retainers. I "Think" that the early parts listing shows 2 different numbers for the retainers & seals. I thing IH changed and started using the same seal and retainer later on in production.

I'd have to do a little more research, I've been living on about 3 hrs of sleep this week. You'll see a post in the "Way Off Topic" soon explaining my brain farts lately?

Wed Sep 26, 2007 7:36 am

I got a lump myself after I read your post this AM. .....and that you would take the time to research MY problems :shock: I wish your family the best.


Wed Sep 26, 2007 11:46 am

Chris, if you still have the carb apart, would be willing to give me a few more measurements? Could you measure the "depth" of the hole for the retainer insert, as well as the diameter of the choke shaft of your carb?

The diameter of the retainer hole is roughly 3/8" right?

I'm guessing you'll go the route and have it "milled" to accept the newer size retainers, but I'm thinking of a fix anyway, never know when this might happen for someone else?

Wed Sep 26, 2007 3:31 pm

I called the local IH dealers around me for the 251306R1 and all they said was NLA(no longer available). I decided I better make a trip to the machinist store to see what the options were for a quick fix. I couldn't believe it, they had a 7/16" counterbore with interchangable tips to buy. The choke shaft measures 1/4" on my carbs, so I bought the 1/4" insert that slides in and tightens with a tiny set screw. The only thing to watch for will be the depth of cut, but that should be simple enough and precise isn't that critical. The choke butterfly keeps the shaft at the correct back/forth location. Here's what the tool looks like.

I can loan it to you Chris. All you'll need is a 3/8 drill. I figured I better get this bit and put it in my carb tool box, cause if there's one, there'll be more show up, now that we know about it.


Wed Sep 26, 2007 3:44 pm

How many flutes does that CB have. I would use a four flute at least , with a hand drill , and take it easy. Will break out the side wall , quick ,fast, and in a hurry.

Wed Sep 26, 2007 3:53 pm

Phil, they only offered them in 3 flute, but they say they're end cutting action only, so there shouldn't be any outward forces from side cutting. I'll experiment to check their statement.

Thanks Phil,

Wed Sep 26, 2007 11:00 pm

Well I called Ken Updike today and he has no showing for my undersized cage and he said to give TM a try. Might be he has something "stashed away" as he has been in the business for years. I believe they are not in shop till the 2nd so that looks like my last resort before the CHIPS fly! Rick, I was thinking that you just might enjoy the projects that keep "popping up"......It gives you an excuse to buy more tools! :{_}:

Thu Sep 27, 2007 5:23 am

I was thinking of the grabbing of the flutes and breaking out , more than the outward cutting. If you are careful ( I know you are more than capable) it should work well. As you know it it can happen it will.

Thu Sep 27, 2007 6:54 am

My FIL has a family friend who still owns a Case/Ih dealership (getting ready to sell out though) and I called him last night.

Gene is about 74, so he's been around for awhile. He couldn't recall a difference in carb parts, but as he said: "Didn't have a whole lot go wrong with them Cubs" but he couldn't recall anything about 2 sizes of retainers & dust seals.

I gave him all the part numbers, and he is going to call me today at work to discuss it further. He does have some NOS stuff still laying around, but he couldn't recall any Cub carb items. As Rick said, that part number is listed NLA with the 3 other dealerships I called.

Back to the 'Fix" on this carb. I've noticed that some of the "Newer" carb kits for some of the MS carbs are now using a "Rubber" insert for the dust seal. That was the direction I was going/thinking in regards to a fix?

Since this is for the "Choke" shaft, having that area "sealed" off 100% isn't a real performance factor? If it was the "Throttle Shaft" area, then I'd be worried, as that are would effect the pressure and performance of the carb system.

I was thinking aloing the lines of experimenting with some rubber O-Rings/washers/brass stock to see what I could come up with.
Last edited by Into Tractors on Thu Sep 27, 2007 8:05 am, edited 1 time in total.

Thu Sep 27, 2007 7:51 am

Since this is for the "Choke" shaft, having that area "sealed" off 100% isn't a real performance factor? If it was the "Throttle Shaft" area, then I'd be worried, as that are would effect the pressure and performance of the carb system.

I was thinking aloing the lines of experimenting with some rubber O-Rings/washers/brass stock to see what I could come up with.
Now that's a thought that would keep the carb original :D I'm sure some brass could be turned in my small "Unimat" lathe that would tap in flush and still have a little step in the inside for some felt or a nice "O" ring. :shock: Good thinking Mike.

Chris, the balls in your court :shock:


Thu Sep 27, 2007 8:04 am

Wow :shock: Can't believe my :idea: might actually have merit :?:

That's why I asked Chris for the dimensions of the shaft size, as well as the depth of the hold. I guess I can go back tonight and check the parts list, compare the part numbers for the carbs, and try to figure out if they are the same or different.

The "rubber" ones I've seen for the MS carbs, are sort of "cone-shaped" which got me thinking last night about using the little rubber washer/seals that are used on some plumbing fixtures for the valve seats?

Thu Sep 27, 2007 9:03 am

OK Boys!
I checked some measurements on my "only child" bottom and they are as follows. Mind you there are no micrometers, etc. around here as of yet so did the best I could. Also high tech measuring instruments I did use were Butt End of.

Retainer depth- Same as new replacement throttle seal. I put old choke cage and new replacement cage side by side.

Cage dia.- Slipped 3/8 HS drill bit into cage seat. Perfect fit. 3/8 then?

Choke shaft dia.- slipped choke shaft into...then 3/16 HS drillbit into. Same size..3/16 then?

You might be onto something here Mike. Really would hate to mill if I wouldn't need to.

Thu Sep 27, 2007 9:17 am

Really would hate to mill if I wouldn't need to.

I agree, I'm not a master using a mill machine, just self-taught. No where near the abilities of Rick, Phil & George and some others on the Forum.

If you saw Phil's comments, I'd be afraid of the walls of the housing blowing out too, but those guys are masters, if anyone can do it, they can.

Now that I have some idea's on the measurements of your carb, I'm also going to look at some other carbs I have laying around. I have some MS carbs for various tractors (Ford, Ferg, etc) and just look and see if those might have the same dimensions? I'm really leaning towards them being closer in size to a carb designed for a smaller engine like a B&S though?

What's really odd is that no one has ever ran across this in the past as I can't find anyone mentioning it in the archives of the Forum, OR maybe some folks don't go as indepth with rebuilding the carbs, and don't take the time to replace those items as the "Cheap" kits don't include those parts?

Thu Sep 27, 2007 9:50 am

It might be interesting if others with early 47's (have seen several talked about) might give their carbs a visual looksee to see if they might have the same setup. I think they might be able to see any difference without removing their carbs. This will benefit them as well when it comes time for a rebuild. Also if they can read their carb number on top casting might help.
"Everybody loves a good mystery!"