IH 300U - carburetor

[Dave H (MI)]

I pulled the fuel line at the carb and got a good strong flow of very clear, clean gas. Removing the filter from the carb is difficult. The brass fitting has a conflict and it is difficult to get a wrench onto it. It is also turned on hard and the combination is making it want to round over. I will look at it again but it is going to take some doing to get it loose without damage. Attaching a picture. Is this the original carb? I have put a couple of kits into IH carbs with varying success. First one I did worked great when I was done. Running 50/50 since. Not a lot of detail in the shop book. Anyone experienced with this carb? Am I getting in over my head?

 

[used red MN]

If that fitting is giving you trouble coming loose pull that hose off and put a thin wall deep socket on it and turn it loose. Even a box end would get on it with the hose off. Was this tractor running a couple years ago? The carb is simple getting, ALL the passages cleaned out is the important part. That means poking through them with a small wire and spraying carb cleaner then blasting with compressed air multiple times. And then when you think youre done go back through them all one more time. I cannot tell you if that is the original carb put on your tractor at the factory, but it definitely looks like an original one for the tractor.

 

[Janicholson]

Testing the flow from the drain (as noted before the small square plug in the bottom of the bowl toward the front. )if nice full flow there, that is not the issue. But the mauin jet and idle circuit could be plugged up and preventing flow. Cleaning it can't hurt. Jim

 

[rustred]

i see a rubber hose connected to carb,better make sure that that hose is a rated fuel line or that is your trouble well i should say it can be your problem. plus just because you have gas running out the bottom does not mean the tractor will run. no sense fiddling around with stuff pull the carb and clean it,.. meaning soak it in gunk the actual carb cleaner. even if you soak it for a day or two dont matter. weight the float down si its covered and gets cleaned up good also. put it in the bottom half then upside down in the gunk. remove all set screws also. pull out the pickup tube and soak also as there is small holes in iy and if they are plugged she will not run. check th needle and seat for wear. if ok just reuse it. you can make i gasket i hope and thats all there is two it. ooh and check your float level and make sure the pin holding the float in is crimped to not slide out. set the main jet to 3 turns out and the mixture to 3/4 turn out and she will fire right up. idle is 400 rpm.
ooh and once carb is off its very easy to get that brass fitting out for the screen.

 

[caterpillar guy]

The deep socket in a six point would be best for not slipping and if you had a allen head plug you could start in the brass fitting if it is that tight would help keep it from crushing or twisting and ruining the fitting.

 

[Dave H (MI)]

No actually. No box end or open end or socket I had on hand would go on there. Would be easy if it were off the tractor. I have a set of deep sockets around somewhere. Might be a little tricky remembering where but I will pull thru the 20-30 tool boxes I have scattered around the place. Will be in one of them.

I just ran out of time again yesterday. I will get it off.

 

[Dave H (MI)]

That is a brand new piece of fuel line from NAPA. It is about 4 long and attaches to the steel line from the bowl. The fuel flow I am getting came out of that line. The carb is still dry and I am tracing the reason in the little time I have right now. I will try to coax that screen fitting off late this afternoon. It would be very unusual for me not to be able to get that off without damaging it. Either that or the needle valve is going to be the reason the gas is not going into the carb. Based on how clean the gas was coming out of the fuel line I am leaning toward the needle being stuck. But, like I said, it may be that some critter crawled into the screen while it was off the tractor and made a home. I will keep plugging along and taking all the good advice I can get.

 

[Dave H (MI)]

That is a brand new piece of fuel line from NAPA. It is about 4 long and attaches to the steel line from the bowl. The fuel flow I am getting came out of that line. The carb is still dry and I am tracing the reason in the little time I have right now. I will try to coax that screen fitting off late this afternoon. It would be very unusual for me not to be able to get that off without damaging it. Either that or the needle valve is going to be the reason the gas is not going into the carb. Based on how clean the gas was coming out of the fuel line I am leaning toward the needle being stuck. But, like I said, it may be that some critter crawled into the screen while it was off the tractor and made a home. I will keep plugging along and taking all the good advice I can get. No pun intended.

 

[lmmare]

That is the correct original carb for a 300U. Rebuilding is super simple and as stated above a good soaking in gunk and some fine wire through the small openings to make sure they are clear, I use a torch cleaning set for that.
30 years ago or so I got rid of all that stuff in line, the sediment bowl and that brass screen thing you are having trouble with, too much a PIA. I adapted down to a 5/16 barb from the tank then to an inline fuel filter then to a piece of 5/16 flared tubing (brake line) to the carb. Hopefully the pics will attach to help make clear what I'm saying. Once I did this all my carb problems went away.

[/img:a0fdd83edf]

 

[Dave H (MI)]

I know what you mean. I have an old MF
swather with a lot of rust in tank. It has a
carb which no one seems to know anything
about. Every year I replace the in line
filter. It runs just fine as long as I do.
No headaches. I will be doing that to my Cub
just as soon as I can get this one out of the
way.

 

[Dave H (MI)]

Got that screen fitting off with the deep socket. The screen was loose in there. Not sure if it should be. Pretty rough but it is not the cause be of the dry carb. Thinking stuck needle.