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574 C-200 Carb issue


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I know most of you guys are diesel oriented, but I'm hoping there is a carb guy on here somewhere.

Quick overview, bought tractor last summer, 1000 hr's, not run for a number of years. People I bought it from, new ignition stuff, gas coagulated. New pump, new line between tanks, new sediment bowl, had someone rebuild carb. Got it running. Got to me, wouldn't start, blew out lines etc. got it to run.

When I first got the tractor, it was running quite rich. Tore carb apart and found main jet on end of solenoid was missing. Got a jet and was much better, was still running on the rich side.

I have put about 6 hr's on it dinking around, wanted to use it some before I tried to tune it better. Hooked up brush hog and was running thru some brush last weekend, about 1/2 hr in, stutters and dies. Tried to start if I choked it. Of course it was as far back in the field as I could be. Walked back, got tools, tried it before I started tearing into things, it started. Got closer to home and drove around under load for about 10 minutes, started to sputter again, head for shed.

Took the carb off, everything looked good and clean. All passages clean and open. Got a new gasket set and put it back together.

Since it seemed like it was not getting gas, I also soaked the main gas line with cleaner for 24 hr's. Got black tar crap out, and seems to be flowing good.

Put everything back together and started. Problem is, runs fine with full choke (just setting, not driving it). If I take choke off, can get it to idle, but as soon as I touch throttle, dies.

It's a marvel schebler carb, about as basic as it gets. I have had it off 3 times trying to find something, but no luck. Bowels are full, choke butterfly definitely closed. Checked for air leaks around intake with torch, nothing. Only one adjustment needle and it does not seem to help, enough anyway.

Any insights or recommendations very much appreciated.

 

 

 

9

 

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May have something there. I checked the operation of the solenoid, but I just happen to remember that I used a fiber washer and not a copper one. I bet it is not getting enough ground to work.

Thank you.

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Nope, good try, but no difference. I checked it on the bench to make sure it was working, and I can hear it clicking when I turn the key on, so I assume it 's working.

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I had an issue like that with one of our 674s once. Everything pointed to the fuel solenoid being bad, it had good power to it, it clicked, but it ran better with it unplugged which definitely wasn't right. I had cleaned and had the carb apart about 4 times,but it always ran the same way. It would always run good at an idle, but not wide open or under load. So after I ordered a new solenoid and the tiny little jet, at around $125 for the pair, I had to wait a week or so for them to come in at the dealer. I wondered if I could get by using a regular adjustable main jet out of my Oliver Super 88 in the 674, as the Super 88 has a large Marvel as well. So I tried it, and it ran just like it had before I started having problems with it. After the new solenoid and jet came in, I installed them, and the tractor was back to running like crap again. I said **** with it and put the Super 88 adjustable main jet back in it and ordered a replacement one for the Oliver for $30, which was a lot less than the one from Case IH. That jet has been in there for years now.

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Duntongw

        Does your tractor have a fuel pump?   If it does then I would put fuel pressure gauge in the line at the carburetor.   Then check the fuel pressure with the engine running with out a load and then again with a full load and watch the fuel pressure as the engine begins to stall.  If there is a restriction in the fittings or lines from the tank,  as the fuel flow is supposed to increase due to the increased load,  the restriction will cause a drop in fuel pressure.   You may have a weak or broken spring in the fuel pump,  which will result in a loss of fuel pressure when the engine is under a load. 

       You may have to add a test tank to feed fuel by gravity to the carburetor.    Then run the tractor under load on this test tank.   You can install a clear test line to the top of the test tank and observe the fuel flow for bubbles or low flow.

       Hope this helps.

GT&T

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4 hours ago, GT&T said:

Duntongw

        Does your tractor have a fuel pump?   If it does then I would put fuel pressure gauge in the line at the carburetor.   Then check the fuel pressure with the engine running with out a load and then again with a full load and watch the fuel pressure as the engine begins to stall.  If there is a restriction in the fittings or lines from the tank,  as the fuel flow is supposed to increase due to the increased load,  the restriction will cause a drop in fuel pressure.   You may have a weak or broken spring in the fuel pump,  which will result in a loss of fuel pressure when the engine is under a load. 

       You may have to add a test tank to feed fuel by gravity to the carburetor.    Then run the tractor under load on this test tank.   You can install a clear test line to the top of the test tank and observe the fuel flow for bubbles or low flow.

       Hope this helps.

GT&T

Nice to see you on Fred. Hopefully things are going well for you.

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GT&T, thank you for the reply. I don't know if you can answer this or not. On a regular carbureted automobile, they used to want 5-7 lbs. pressure, of course this is with having to bring fuel from the tank at the back of the car. On a tractor with an updraft carburetor, and the tank basically gravity feeding, is this still a requirement, or as long as it keeps the bowl full it's happy?

Thank you for your help.

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Duntongw

       You are right that the carburetor must be kept full of fuel.   However you need to be sure that the carburetor is kept full of liquid fuel and not just have fuel vapor going to it.  If there is a restricted fuel line at the tank and the fuel pump can pull air or vapor in the line from the sediment bowl then the carburetor will be getting vapor pressure and not liquid.   This is what is known as vapor locked.

GT&T

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On 4/17/2021 at 3:00 AM, bitty said:

Nice to see you on Fred. Hopefully things are going well for you.

Bitty

     Thank you.   Things have been going very well.   I have been following along,  this forum has been very therapeutic.

Fred

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`There is something really basic that I am missing here.

Background: Bought tractor last summer, has 1000 hr's on which I have not found anything that says otherwise. It had set for a number of years, and gas had turned to tar. Place I bought it from replaced various lines etc. and fuel pump (Don't know if this is an aftermarket or IH, no IH markings). Got it running. I have used it a little and was running fine, but it was not under a load. Under load seemed to be running out of gas.

Carb is clean, all lines clear, gas tank about half full, etc.

I got a new fuel pump from NAPA, looks exactly like the one that had been put on last summer. When this pump is on tractor, I am getting gas from tank to pump, but not getting anything out of of the pump. If I take pump off, put a little gas in the "in" port and stroke it by hand, it will shoot gas for 10 feet. Old pump was acting same way. Looked in bore at cam lobe and everything looks fine, rotates, no wear, has runout etc.

Sediment bowl is behind axle and the main line has to get up over axle and back down to fuel pump. If I cup my hand over tank fill hole with a hose in it, I can blow a full stream of gas out line at pump. I do this when fuel pump is on engine to make sure it has gas.

Called local IH dealer to see if he might have a IH pump that I could compare to, no luck. I tried pouring some gas in carb throat to get motor to run for 10 seconds or so to see if it would push it thru, no luck.

It almost acts like pump arm is not moving far enough to get the pump to push anything. It has only the gasket between it and block, tried without gasket and still nothing. Comparing old pump to new pump arm, preload and pump points appear to be the same.

I hate to put $180 into another fuel pump (IH rebuild). Am I missing something dumb here?

Thank you for your help.

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Duntongw

      When I read this statement it answers a lot of my questions. 

57 minutes ago, Duntongw said:

Sediment bowl is behind axle and the main line has to get up over axle and back down to fuel pump. If I cup my hand over tank fill hole with a hose in it, I can blow a full stream of gas out line at pump. I do this when fuel pump is on engine to make sure it has gas.

        Next step.   Hook up the fuel line from the tank to the fuel pump,  with the pump off the engine block,  and the outlet of the pump unhooked.   Then pump the pump lever by hand,  does the pump squirt fuel when you do?      Then hook the pump back to the engine block and spin the engine over,  does the pump squirt fuel then?   If it does,  then hook fuel line to outlet of the pump,  and unhook the fuel line from the carburetor.  Spin the engine over and check the fuel flow out of the line to the carburetor,  it should squirt full squirts every time the camshaft operates the pump lever.   You should also hold a couple of pounds of fuel pressure at the outlet.    If you do not get any fuel flow with the outlet line disconnected   then you may have a  cam lobe worn or the fuel pump lever may not be touching the cam lobe.   ( Think,  wrong pump, bent pump lever,  mounted upside down,  pump lever not long enough. )     Remember just because the new pump is the same as the old one, does not make it the correct pump,   you had the same problem with the old pump.

GT&T 

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Fuel line hooked to pump, manual operate, shoots gas all over, mount to block, gas actually running out of "out" passage, turn over, no change. Guess I better order a IH pump. Pretty much impossible to not have pump/arm in correctly. 

Thank you again for your time and help.

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Just to follow up, I seemed to have (2) issues, one not apparent, one dumb mistake.

Previous owner had replaced fuel pump. I replaced it with one from NAPA that matched, didn't work. Ordered one from IH, good to go. I will make another post that deals just with this, just for information for others (574 C-200 fuel pump).

Second problem was, it would only run when choked. I assumed it was starving for gas, nope, starving for vacuum. After tearing carb apart for the 4th time, I realized that the venturi was upside down, and did not fit tight enough to draw vacuum. It sets into a brass ring, and actually fits better the way I had it, but it did not seat good enough on the other half.

Anyway, so far so good. Have to wait a few days for weather to straighten out to try it.

Thanks to everyone for their help, very much appreciated.

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