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privateer

K301 running issues - stumped? - need help please

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privateer

my c-120 auto doesn't want to run unless the choke is closed with full throttle. the second I take the choke off it stalls. I've had the carb off a few times now this spring. It's clean as a whistle.

 

idle needle looks good

the 4 high speed needle holes are clean of debris

both needles adjusted to 2 turns

no play in the throttle body shaft

changed out the float valve needle and seat last year

new fuel baffle shield and gaskets.

float is lever with carb body

 

Carb seems to fit tight on the motor. Removed gas line, gas will gravity flow on it's own when hose goes below tank. Cranked the engine with the fuel line in a clear bottle. Get a small fuel surge every engine revolution.

 

 

Could it be a weak sparkplug causing this problem? clean the points, new condenser?

  

 

I'm stumped, where should I be looking to get this horse back to work?

 

Thanks,

 

Rich

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oldredrider

Just for grins, do you have another carburetor to try on it?

How is the timing (points settling)?

Sure, try a NEW plug, and let us know.

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KATO

How long was it sitting ...maybe you have a sticking valve :confusion-shrug:

Edited by KATO

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shorts

If it won't run without the choke completely closed it's a carburetor problem, You describe wide open throttle and closed choke, that indicates that fuel is not siphoning up the main jet tube and being atomized in the venture without the increased suction in the carb throat from closing the choke.  remove the carb and disassemble the float assembly and mixture adjusting jets, you can leave the throttle and choke blades and shafts in soak the carb in carb cleaner or a solvent like lacquer thinner over night, then blow out all of the passages real good with compressed air, pay special attention to the main jet/sump tube to get it clean, it's the structure that the float bowl retainer threads into. then take an aerosol can of carb cleaner install the little plastic straw and blow carb cleaner thru the passages 1 at a time while checking to make sure they are clean and clear. reassemble the carb, lightly seat the needles and then preset at about 1 1/2 turns out and start the engine and fine tune the idle and high speed mixture needles

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pacer

Should be easy enough to determine if fuel - that needs to be determined whether fuel IS the problem so you can move on to other areas -- or not.

 

Take some thing flammable (I like brake cleaner) WD40, etc and as you come up to full throttle, instead of choking it squirt the alternate fuel into the carb opening in a steady enough amount to maintain running - or not. If it will run on this alternate fuel, then your carb or fuel pump or lines or something fuel related is wrong. If the alternate fuel doesnt do any thing then its  ----- something else!

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Ed Kennell

If it won't run without the choke completely closed it's a carburetor problem, You describe wide open throttle and closed choke, that indicates that fuel is not siphoning up the main jet tube and being atomized in the venture without the increased suction in the carb throat from closing the choke.  remove the carb and disassemble the float assembly and mixture adjusting jets, you can leave the throttle and choke blades and shafts in soak the carb in carb cleaner or a solvent like lacquer thinner over night, then blow out all of the passages real good with compressed air, pay special attention to the main jet/sump tube to get it clean, it's the structure that the float bowl retainer threads into. then take an aerosol can of carb cleaner install the little plastic straw and blow carb cleaner thru the passages 1 at a time while checking to make sure they are clean and clear. reassemble the carb, lightly seat the needles and then preset at about 1 1/2 turns out and start the engine and fine tune the idle and high speed mixture needles

:text-yeahthat:  Gotta be starving for fuel

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privateer

Thanks for the replies and help. The tractor stopped running without warning last fall. The in line clear fuel filter is like new.  

 

 I had a short time yesterday to tinker. I cleaned the points with emory cloth, pulled the plug to check spark. Saw a nice blue spark. Unscrewed the high main jet. Sprayed carb cleaner down the sump tube. Readjusted to 2 1/2 turns. It fired right up with closed choke and minimum throttle. I let it run and warm up for 10 minutes with closed choke and idle throttle. Ran Ok, governor searched and worked properly every so often. I used my finger to cover the two holes on the choke blade. Felt a suction, the engine increased rpm's a bit. The second I open the choke the engine quits.

 

I am going to replace the H10C plug later. Pull the carb and check again. I'm guessing a piece of rubber is stuck somewhere.

 

Could the bowl screw be messing with the intake of fuel up the main tube? By tightening the bolt too much?

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pfrederi

I would recommend you not use emory cloth to clean points.  It can leave grit.  They sell a points file.

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shorts

You just proofed that fuel starvation is the issue again when the engine picked up speed when you blocked off the air holes in the choke plate, you have a restriction in the sump tube, it's either a blockage in the fluid passage or a blockage in the air passage that lets the low pressure from the venture to suck enough fuel. the gasohol fuels corrode the small passages in white metal castings of the carb blocking them with the growth and contamination from the corrosion, complete disassembly and a thorough cleaning is the proper cure, the fast fixes aren't working so far.

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rmaynard

My guess is the same as all the rest of the guys that are saying that it's a fuel starvation problem. Sometimes the inside passages of the carburetor get so corroded from moisture held in the gas by the ethanol in it, that it is almost impossible to get it clean. The time, labor, parts and aggravation involved in cleaning and rebuilding is sometimes more than the cost of a NEW aftermarket carburetor that is now available on eBay for less than $60.00 delivered.

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privateer

installed new plug

removed and tore apart carb, soaked and blew out all orifices, reassembled

 

Will install back on tractor today, keeping my fingers crossed.

 

If not, a new carb will be on order.

 

Thanks for all the advice so far

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privateer

Well, installed carb back on tractor.. Still the same problem. As soon as I open up the choke it stalls. It will run choke closed at idle and will run and stay running when increasing throttle about half way.

 

Could a bad intake gasket cause these symptoms?? perhaps the sheet tin is causing a gap allowing a vacuum leak. I will buy another gasket. I noticed they make a thicker gasket to prevent  the carb from heating up too much.

 

I will also gravity feed the carb to eliminate any fuel delivery problem. weak manual pump, clogged filter, clogged tank screen,

 

Boy this is frustrating.

 

any suggestions?

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C-101plowerpower

How old is the fuel? I've had problems like this with old fuel, some fresh gas solved it

Koen

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privateer

update on why the motor wont run unless choke fully closed. Fuel starved!

 

It ended up being a weak manual fuel pump. I initially checked and ruled the pump out  because it was pulsing out fuel.  

 

I tore it apart and there was a piece of rubber stuck in one of the flappers.

 

Reinstalled. Runs like a top!

 

Thanks for all the help and suggestions!

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