F-12 carb rebuild...Tom Fleming

Seth Boyer · Sep 3, 2014

Tom I was curious if you ever got around to making any of the idle metering jets for the F-12/F-14 carb?
You may remember I was deep into rebuilding a F-12 a couple years ago. Well it got pushed back and 2 years later I'm hard at it again. Motor should be sitting on the frame rails in a couple weeks. All I lack is rebuilding my carb and putting my radiator together.
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Tom Fleming · Sep 4, 2014

HI Seth, no not yet. I have the tooling now, just need to sit down and do it. When I do make a couple, you are on the list. I have been incredibly busy this summer, and have not had much time for tractor projects..........

Seth Boyer · Sep 4, 2014

Tom could you explain again what you found would work using the same jet off an M or H carb? Did you have success using it? What size tap? The carb I plan to use has some of the jet left in the body of the carb. I think I may have some luck threading the brass that's left over.

Tom Fleming · Sep 5, 2014

Seth, here is what I know. The jet itself is a press fit, no threads. it is a 1/8" (0.125) brass tube, with a 0.021 jet opening (#75 drill, hence the 75 on the part number) and a 1/16 (0.0625) id. The H and M jets would probably work, if you can thread the carb base. I'll have to look up the thread size again on the H and M jets. I also looked at using a Cub jet, and I know those threads take a 4-40 tap.

Lastly, there is a difference between a gas only carb and a dual fuel carb. That jet passes through a vacuum port. The gas only jet is a solid tube, and the dual fuel one has a port in the tube at 90 degrees part way up that opens into the vacuum port. I have a mostly intact broken one, and a NOS gas only one. I'll dig them out and get some specific measurements for you on the location of the dual fuel 2nd port, and also the overall length of the jet.

Seth Boyer · Feb 16, 2015

(quoted from post at 10:44:56 09/05/14) Seth, here is what I know. The jet itself is a press fit, no threads. it is a 1/8" (0.125) brass tube, with a 0.021 jet opening (#75 drill, hence the 75 on the part number) and a 1/16 (0.0625) id. The H and M jets would probably work, if you can thread the carb base. I'll have to look up the thread size again on the H and M jets. I also looked at using a Cub jet, and I know those threads take a 4-40 tap.

Lastly, there is a difference between a gas only carb and a dual fuel carb. That jet passes through a vacuum port. The gas only jet is a solid tube, and the dual fuel one has a port in the tube at 90 degrees part way up that opens into the vacuum port. I have a mostly intact broken one, and a NOS gas only one. I'll dig them out and get some specific measurements for you on the location of the dual fuel 2nd port, and also the overall length of the jet.

Tom have you looked any further into this? No rush if you haven't. I may look into using a jet from an H or M. I'm going to be experimenting with some different carb set ups on the f-12 soon. Want to bore out the venture and open up the fuel jet some.

Tom Fleming · Feb 16, 2015

Seth, sadly I have been too busy to get this this. Try the H and/or M jets if they meet the specs I poster earlier in this thread. I have one NOS original, but I planned on keeping that for use as reference when I finally get to this.

F-12 carb rebuild...Tom Fleming

Seth Boyer

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Tom Fleming

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Seth Boyer

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Tom Fleming

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Seth Boyer

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Tom Fleming

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