460 carburetors

Overhauled a 460 including rebuilding the carb but only way I can get it to run is with choke fully extended. No response to adjusting main jet or idle screw. Now just worked on a second 460 and have the exact same problem. Both carbs were soaked in cleaner and all ports air blown and new kits installed. Any ideas will be appreciated!

First thing to look at is what kind of fuel flow do have from fuel tank,is tank vent on cap plugged,screen on carb plugged.Scott

Soaking isn"t enough, you need to clean out the thing with real small tip cleaners. Air fits through small openings better than gas so even if it seems ok it"s still restricted. disassemble the carb completely and run the tip cleaner in every hole you can. I had the same problem on my 400 and that"s what it took to make it run without the choke on.

There is really no adjustment for the main jet. For max power turn the main jet screw 5 turns out. It can be turned in for lighter loads. It is not adjusted by turning it in until rough, out until smooth like the carbs prior to the SH and SM. If this does not work then clean the jet as mentioned below.

Adjust your float settings again and the float valve needle.

="SALTY"; tell us, did you have any such problems before the overhaul?

You may have already done this but,
* check the from the factory 'in-line' cylindrical screen that [u:f379b83bbd]should[/u:f379b83bbd] be slid in the end of the fuel line that goes into the carburetor.

* check the tank for any debris that could find a way to intermittently float into the intake at the bottom of the fuel tank. From personal experience with my Farmall 460 gas; last summer I had hauled a load of brush, a few miles to a dump site and upon returning the engine would only run and poorly so, with full chock; suddenly run a few feet and repeat. Took over an hour to go a few miles. I had to check more than once and with differing light and finally was fortunate to find a 'floater' that would obstruct the little opening at the tank bottom. I suppose oft times it was hidden from my view by the fuel gauge sending unit. I'm gonna post what I have a few times; maybe you have this info; maybe others will see it also. Please post back your findings - results. Good luck.

Adjusting the carburetor

McCormick Farmall and International 460 – 560

per the Preventative Maintenance Manual dated 6-20-58

"The engine and carburetor are correctly set when shipped from the factory...Start the engine and allow it to operate until thoroughly warm before making any adjustments.

... with the engine thoroughly warm, turn off. Close the [top needle] idle adjusting screw to its seat; then open one turn. The [bottom adj. screw] main fuel adjusting screw can be used to reduce the amount of fuel going into the engine when under light load conditions. However, when heavy work is to be performed in which the FULL POWER of the engine IS REQUIRED, the fuel adjusting screw should be set five turns off its seat. With the engine running at fast idle, turn in the throttle stop screw a few turns to prevent the engine from stopping when the throttle is closed. Start engine, close the throttle by pushing the engine speed control lever all the way up. [I like the way they worded that.] The throttle stop screw can be backed out until the desired idle speed (approximately 425 r.p.m.) is obtained. If the engine misses or rolls, the idle adjusting screw may be adjusted either in or out until the engine operates smoothly.

Sounds like the venturi is installed upside down.

Sorry to you guys - I got sidetracked for a week. All your thoughts will be investigated again. Both tractors had tight engines and so had not run for a while. We tried to flush the gas tanks but will redo that also.