Carb still cutting out

Adobejoe

New User
Replaced points and condenser. Same issue: it will fire for maybe 6-10 times then die, then carb accumulates gas in base. Pulled plug and visually watched spark against ground of block. Good strong spark. I think there is a primary and secondary jet, or passage in carb. I think primary jet is not drawing or clogged or something going on. Wish I could post a picture. Can I use compressed air in main passage? Pb blaster?

I also replaced fuel filter and line. There is plenty of gas to carburetor.

Ideas.

Andy
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This post was edited by Adobejoe on 05/11/2022 at 07:48 pm.
 
You say good strong spark but does it jump a 1/4 inch gap or more and is blue/white in color?? You replaced the condenser but now days it is common for them to be bad right out of the box. I have not replaced a condenser in well over a decade if not two.

One thing that could also help us help you is what tractor. Few ever had a in line type filter and many times a filter like that can be the problem
 
I use compressed air after I clean. I use
stranded copper wire. Cut off insulation
and take a couple strands, twist them
together and chase the ports. Just don't
hit the float with compressed air. It can
collapse it.
 
sorry the tractor is an international H of approx 1950s vintage. I had issues with the standard glass bowl screen valve below the tank not sealing. Drip drip drip. A day or two later there is your 10 gallons of gas ($4.25/ gallon) gone. So after trying a second glass bowl screen arrangement I replaced it with a inline filter and cheap (plastic) valve.

I just spent $30 on a new points and condenser at the advice of an earlier poster.


Would be nice to hear someone talk about the carburetorit has a strong spark..as I mentioned, I suspect the primary jet is not passing fuel. Please do not tell me to buy a carburetor rebuild kit, instead tell me about the primary fuel passage into the intake manifold.how to assess and how to clean,,,, Any ideas?
Andy
 
I've rebuilt who know how many carbs. You need to soak them blow every passage way out with air and spray carb cleaner and poke out all the passage ways at least 3 times. I have a rebuild H carb right here on my desk
 
..Can I used compressed air in the main passage?..
That depends on you definition of the ..main passage..
it is possible to collapse a float if the float bowl
chamber is pressurized to high. All the answers you
see here about using compressed air are meant to
utilize it while they have it disassembled for cleaning.
Where are you saying there is plenty of fuel flow to the
carburetor? If it is from the new black hose next to the
newer looking brass fittings you are overlooking
something you probably do not know about. You need
to check the flow at the square headed plug that is
sticks straight out towards you if you stand beside the
tractor, it is low on the carb. When you pull it out there
will be good flow of about 2 to 3 measured cups. That
will empty the float bowl. It should continue a good
stream and not slow down to just a trickle. If is does
slow down to a trickle here is the part you probably did
not know. The old brass fitting that is screwed in the
carb where you screwed your new fitting in; you need
to screw the old fitting out. In that fitting is a small
screen that is likely plugged. The link shows an example of what it looks like.
Poke here
 
When I do small engine carbs, I poke a bread wrapper wire through all holes and passage ways. If you dont, they will bite you in the arse.
 
I've opened the drain plug and shot air in the fuel mix screw
many times, no damage.
There appears to be a leak at the top of the carb. Might remove
the carb and use silicone to seal it or find a gasket..

I've never seen the gismo on top of the carb with a black hose
connected to it and the other pipe. I have no clue what you
have..The governor is connected to the carb. I'm at a loss..

Usually the fuel line is connected directly to the carb and the
gas throttle plate is part of the carb.
 


Per your request I will "talk" about your carb. "carb accumulates gas at the base" leads me to guess that after it fires a few times but doesn't run, that gas is possibly running out somewhere. If my guess is correct this is a very common occurrence with old tractors. Most old tractors, like your H, have updraft carburetors. When cranked for a few seconds without starting a lot of gas will be sucked up into the manifold, and as soon as cranking stops this gas will be pulled back down by gravity. "I think primary jet is not drawing or clogged or something going on" tells me that you think that instead of gravity at work that the 1.5 inch passage through the carburetor to the manifold is blocked. This is highly unlikely. You can get a better idea of what is happening by taking a spark plug reading immediately after cranking. Just remove two plugs and look at them. If they are dry or just slightly moist you are not choking it enough. If they are truly wet you are getting gas to the cylinders but there is probably an ignition problem. Try this then post back. I see no evidence of a leak near the top. Be wary of applying silicone seal. it has lead to additional problems for guys making repairs.
 
Thats the better setup, in-line filter (gravity flow)and
shutoff valve. Should put your valve ahead of filter
though. A ball valve is much better.

Doesnt matter what was on these tractors, the correct
inline filter does a much better job, you can cross these
numbers- Napa 3031- 1/4, 3032- 5/16, 3033- 3/8 line.

Your carb needs cleaning.
 
Reading about your problem several things come to mind;

-If as you say the tractor has been converted to 12 volt and it has a ballast resistor it is possible you are getting spark while cranking but due to either a wiring issue or a failed ballast resistor you will have no spark once you release the start button.

-Has anything else been checked? compression, valve adjustment etc.

-You say you have a good spark, was that checked on one cylinder or all cylinders?

-Could firing order be mixed up?
-Moisture under distributor cap?
-One or more old wires shorting out?
-Badly restricted air filter?

-Regarding your carburetor, if you are adamant the carb is causing the problem then remove the air intake hose from the carb and squirt a teaspoon of gas directly into it and try starting, if it catches and runs good for a few seconds then you have confirmed you have a fuel problem. If you are getting a good constant flow when the drain plug is removed then it is time for a proper carb dismantle and cleaning.
 
REALLY,
Never seen any carb like that one on my Farmall C.
Goes to prove I haven't seen everything..
 
I have seen many a floats flattened due to air pressure being applied through the idle or main jet.
If you pull throttle to open butterfly you may get away with it or have air cleaner hose off and
choke is open.

You can take the main jet adjusting screw out, leaving packing nut in place and run a tag wire or
similar small wire through main jet. This won't do anything for the getting crud out of the venturi
nozzle though.

Have you taken the drain plug out of carburetor to see if a good stream continues to run through
carb.
 
(quoted from post at 20:31:11 05/11/22) I've rebuilt who know how many carbs. You need to soak them blow every passage way out with air and spray carb cleaner and poke out all the passage ways at least 3 times. I have a rebuild H carb right here on my desk

Old, you want to do a swap? I will send you two for one?

Andy. [email protected]
 

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