860 Carburetor Issues?

[jcmorgan31]

Getting ready to do a search and start reading but thought I'd ask the question in case anyone had a quick answer.

Finally got all the electrical parts on my tractor and cranked it over this afternoon. It actually tried to fire and run but never really kept itself running. I feel like it is a fuel issue. I removed the carb, took it apart and cleaned everything and put it back on. If I put my hand over the air intake and crank it, it will fire like it is trying to start and when I pull my hand off gasoline runs back out of the air intake. Seems like the only way it can get fuel is when the air intake is completely blocked (doesn't seem to get it with only the mechanical choke).

Anything in particular I should look at with this carburetor?

 

[Tim PloughNman Daley]

JC-
Did you do The Fuel Flow Test when you first started having issues and before you took it apart? The FORD 800 Series Tractor used the Marvel/Schebler 593 Carburetor
early on and the 706 Models later on. Either will work. Did you rebuild teh carb since you already had it off? Removing the unit and simply 'cleaning everything' may
have been a waste. Did you replace Main Needle & Valve? Did you check the float level and reset if needed? Did you remover the brass fuel inlet elbow and clean the mesh
screen? Often this important screen is neglected or maybe the owner is not even aware it is there and gets plugged. Are you set up with the OEM 6V/POS GRN electrical
system or did you try a 12V switch over job? Some fuel issue guesses turn out to be electrical and vice versa. Do the Fuel Flow Test first with engine cold. Valve
closed, get an empty coffee can or drip pan and place underneath the carb. Remove the Carb Drain plug on the bottom - will be, should be, a brass NPT fitting with a
7/16 hex head. Open the Fuel Sediment Bulb Valve 2 Full Turns. Observe if fuel flows at a steady stream and fills a 1 pint jar in two minutes. Yes? Carb seems to be
OK. No? Obstruction could be in the carb or in Sediment Bulb filters. Then, close Valve and replace drain plug. With a 7/16 Flare Nut Wrench, loosen the fuel line
fitting at the carb brass elbow inlet and slide gently off to the side so it points down into coffee can. Open Fuel Valve on Sediment Bulb Tow Full Turns and again
observe if fuel flows at a steady, uninterrupted stream and fills a pint jar in 2 minutes. Any flow hesitation, stopping and starting indicates a flow blockage
upstream. Sediment Bulb screens would be first to clean or replace. If tank is full of debris and rust flakes, those can hinder flow to Bulb when Valve is open. Bulb
needs to be cleaned but don't go buy a new unit. The Valve is a usual culprit as the rubber (some are now vinyl) seal wears gets chewed up and pieces can plug up fuel
line and ports. Fuel Valve can be gotten new and replaced if so, but you do not need to buy a whole new Bulb unit. Fuel line should be the OEM equivalent standard 1/4
steel line which can be purchased new pre-bent to OEM specs. Do not use plastic, nylon, rubber, copper, or aluminum lines. Fuel fittings use a special thread too. They
are 7/16-24 UNS, the standard used for fuel and brake lines. If upstream test passes, blockage then is in carb so will need to be removed and rebuilt with a good kit
likE the TISCO C547AV. Once Fuel Flow Test passes, and problem still exists, move on to electrical. When rebuilding a carb, always set the Main and air idle mixture
screws to the OEM specs in your manuals. You may have to tweak things once tractor is running, but for now don't be monkeying with them.


Tim Daley(MI)

 

[jcmorgan31]

Thanks for the reply!

I just got this tractor from my cousin a few months ago. His dad had been messing with it for a long time and couldn't get it running. So, I didn't "start having problems", just trying to piece it back together correctly and see if it will fire.

There was plenty of fuel entering the sediment bowl ( I change the screen on it) so I didn't do any flow testing. I don't see a brass elbow with a screen in it on this tractor like my Ferguson TO20 had on it. This fuel line runs straight into the sediment bowl.

I also didn't rebuild the carb. I just wanted to take it apart and make sure there wasn't a wasp or mud dauber nest in it or who knows what else. There were cobwebs in the venturi and some other insect debris inside. I was just looking for obvious issues really and making sure orifices weren't clogged.

I did set the two needles to the owners manual recommendations.

Sounds like I should rebuild the thing just for some piece of mind.

 

[pomester]

Check the manifold nuts and make sure they're tight. Had something similar once, turned out I hadn't torqued the nuts after having the manifold off. Worked for quite awhile until it didn't...

Easy to check and doesn't cost anything.