Farmall SH Fuel Flow and Timing

Hey guys! Still working on this darn SH. I had talked with Matt at Motec Engineering and he gave me a couple things to try with the carb and it didn"t seem to work so I am sending him both the carb and distributor to go through so I can eliminate those variables. He has an engine setup on a dyno and checks/tunes everything before he sends it out.

If you don"t remember I"m having trouble with it running rough at idle, stumbling in 4th and 5th gear without full choke and randomly dying after its warm (starts right back up).

I think its still a fuel issue. I think I have good fuel flow, what do you think from the picture? Tank is clean and I can drain the whole tank and the flow is steady/consistent as shown.

Also, when I go to put the distributor back on, I noted where it was so I can get it close, but what is the correct procedure for timing with a light? I noticed the tractor only has one mark on the crank pulley, should that line up with pointer at idle or???

Thanks for the help!

Set the timing at TDC compression on #1 cylinder & forget it. This is not a high performance engine and runs at a low (compared to cars & trucks) RPM. Timing advance can be checked later.

As Wayne said you don't need a timing light, unless the engine has been modified as with fire crater pistons. Line the marks up at TDC with the engine off. Install the distributer with the rotor pointing to #1 on the cap, after the distributer is installed rotate it toward the block and then rotate it out until the coil wire gives a spark when held next to the nut on the distributer. About all that could be wrong with the distributer that "might" cause those symptoms is a loose shaft. I think I mentioned before that your carb needs a good cleaning with real carb cleaner, not the spray on stuff. Disassembled and all parts and the body soaked perhaps overnight. Blow out with compressed air. See that the passages you are blowing out let the air out somewhere. You can carefully clean the idle and main jet with a small wire.

Fuel flow in your photo is more than adequate - no problem there!

From your description (stumbling, rough idle, choke req'd in 4th - 5th) the problem is a chronic lean condition. If you cannot correct it by opening the carb load screw the carburetor needs disassembly and a THOROUGH cleaning.

As for timing you don't need a timing light. Simply set the pulley notch at the pointer with the distributor button pointing to the #1 nipple on the cap. Now stick a mirror so you can observe the ammeter while standing alongside the distributor. Turn on the ignition and watch the ammeter as you slowly rotate the distributor back and forth. Timing is correct the instant the ammeter returns to center while the distributor housing is being rotated COUNTERclockwise.

Don't forget to turn off the ignition as soon as you are done!

I have had the carb apart multiple times to clean already and am not having any luck. I have never had any trouble with other carbs I have gone through. I have even tried bead blasting and baking this one in a heat treat oven to burn anything out. New idle adjusting screw but the load screw is the one that came out of it and has a very small groove worn, wonder if that's causing any problems. I also wonder if someone has previously closed them too hard and damaged the seats? If it has any relavence, this is the carb that had the broken jet inside and bent choke plate when I got it. Venturi looms like it has been dropped a few times. I smoothed the rough spots off a little but that's it.

Not many Super H tractors still running with original pistons so hard telling what is in there. If it has fire crater and you have original distributor your advance will be way too much. Timing with a light , you have to know what you are looking for. Almost all distributors on those tractors will start to advance at very low engine speeds and that is why you set timing at full throttle at max advance and then observe where it is at mid and slow speeds. If it is over advancing at low speeds you will have a rough running engine. If you have a rain cap on it the thing will slap back and forth and it should not do that if correct. I often just static time them because I am familiar with how a good distributor feels and good running engine sounds. If not, then you have to go farther in you checking and adjustments. Standard advance is 30 degrees btdc and fire crater is 22 degrees btdc at full throttle. The springs they use on fire crater are very weak and often over advance at low speeds. Far as carburetor, it could be anything. Might not even be correct one, wrong venturi, wrong main jet, wrong nozzle, wrong idle jet or damaged idle jet. If your guy checks it all assembled on a dyno you should be in good shape though.

You WILL NOT be disappointed in Matt's work.

Have you used him before? I talked to him a couple
weeks ago and he is the one that recommended
baking the carb. Hopefully he can find something!
At least sending it off will eliminate a variable
for me. Will post back once I get the carb back
and engine retimed. Thanks guys!

I have used him for my SMTA and H carbs. He did some work on the SMTA carb to get more power out of the tractor. It certainly worked. I easily one the points championship the first year after he did the carb work. I also cashed more checks at brush pulls than I ever have. The only things I changed were the carb, plugs and wires, and timing. I am POSITIVE the timing made a huge difference, but the carb had a lot to do with it.

I say I'm positive the timing had something to do with it because I pulled at a local pull and did bad. I then retimed the tractor and pulled the next day and cleaned house. With the tractor timed at TDC it didn't have near the lugging ability. I have NO IDEA how the tractor is timed. IIRC he advanced the timing quite a bit, but Pete will be able to straighten me out on that. I don't understand why advancing or retarding would change the lugging ability. Pete, if you can let me know the disadvantages of doing this I would appreciate it. I use the tractor on the plow and I don't really want to blow it up.

I've had bad luck with shipping carbs. Doesn't matter who did the work, the UPS/Fedex guys kick, punch, throw, roll, slam, and smash the boxes. By time time it gets back to you the float's all messed up and you gotta pull the carb apart yourself and rebuild it again.