Carburator Trouble.

L.Fure · Sep 18, 2015

A while back I posted about wanting to buy a new carburetor for my 340 International. The consensus was for me to rebuild the carburetor that is on the tractor. The main problem I was having was a suspected leaky needle valve which caused to carburetor to flood while sitting. I did rebuild it, and it still has the same problem. Now what?

IanC · Sep 18, 2015

The modern gas is not the same density as the old gas. Set the float a little deeper in the bowl so when it displaces its weight (which hasn't changed) in fuel it will close the valve with the same force as the good old days.

chuck bergstrom · Sep 18, 2015

Hi, A carb can always be rebuilt. The main this is: Did you soak it out overnite with a
good carb cleaner? This is the most important. Swishing it out with gas is not enough.
If you havent done this do it now. Chuck

chuck bergstrom · Sep 18, 2015

Hi, Also did you put a new (needle and seat)float valve. That is also important. They
are not that expensive. Do these two things and it will work. Chuck

IAtractorKid · Sep 18, 2015

If you can't get it figured out, send it to Matt @ Motec Engineering.
I have sent him several troublesome carbs over the years and he does
excellent work at a reasonable price. Plus after he goes through them,
he tunes them on his engine dyno so they are set correctly when you
receive it. Usually $75-150 depending on what all needs done.

rustyfarmall · Sep 18, 2015

(quoted from post at 13:30:55 09/18/15) A while back I posted about wanting to buy a new carburetor for my 340 International. The consensus was for me to rebuild the carburetor that is on the tractor. The main problem I was having was a suspected leaky needle valve which caused to carburetor to flood while sitting. I did rebuild it, and it still has the same problem. Now what?

Did you inspect the float for pinholes? Did you clean the new needle valve and seat before installing? Did you set the float to the specified height?

rustyfarmall · Sep 18, 2015

(quoted from post at 13:35:48 09/18/15) The modern gas is not the same density as the old gas. Set the float a little deeper in the bowl so when it displaces its weight (which hasn't changed) in fuel it will close the valve with the same force as the good old days.

Really? And where did you come up with erroneus information?

Steve@Advance · Sep 18, 2015

Some rust or trash may have come down the line and gotten in the needle valve.

Take the fuel line loose from the carb, open the fuel tank valve fully, give the line a few flicks to shake
anything inside it loose, catch what comes out in a clean glass. If there is anything but clean gas, there is
contamination in the tank.

Another trick to clean the needle/seat is to turn the fuel valve off, let the carb run empty, or remove the
drain plug. Then open the fuel valve. This will let the needle valve open fully and flush any debris that may
be caught there.

glennster · Sep 18, 2015

also check to see if the float is rubbing on the side of the carb bowl.

old · Sep 18, 2015

So is the needle a rubber tipped one or a brass one?? If rubber tipped it needs to have a set put in it to work as it should/ You simply put he needle in a seat and tap on it a number times. Then pull it out and you should see a circle in the rubber tip.
Also you have to have the needle seat good and tight and have the right gasket under it and of course have the float set right

rustred · Sep 18, 2015

ha ha ha! almost sounds like lawyer talk, lots of words but no sense.

showcrop · Sep 18, 2015

(quoted from post at 14:11:48 09/18/15)

(quoted from post at 13:35:48 09/18/15) The modern gas is not the same density as the old gas. Set the float a little deeper in the bowl so when it displaces its weight (which hasn't changed) in fuel it will close the valve with the same force as the good old days.

Click to expand...

Really? And where did you come up with erroneus information?

Actually Ian C is probably partly correct. There would have to be a slight difference in the specific gravity between straight gasoline and gasohol, however the amount of adjustment required would probably require measuring equipment that could measure to a thousandth of an inch so the adjustment would probably be unfeasible and the result unmeasurable, and completely ineffective.

L.Fure · Sep 18, 2015

(quoted from post at 21:58:30 09/18/15) Hi, A carb can always be rebuilt. The main this is: Did you soak it out overnite with a
good carb cleaner? This is the most important. Swishing it out with gas is not enough.
If you havent done this do it now. Chuck

I cleaned the carburetor parts in an ultrasonic cleaning machine with a strong detergent as a cleaning agent. The inside of the carburetor is as clean as it can be.

L.Fure · Sep 18, 2015

(quoted from post at 22:01:32 09/18/15) Hi, Also did you put a new (needle and seat)float valve. That is also important. They
are not that expensive. Do these two things and it will work. Chuck

The rebuild kit came with all the necessary parts to rebuild it.

L.Fure · Sep 18, 2015

(quoted from post at 22:09:58 09/18/15)

(quoted from post at 13:30:55 09/18/15) A while back I posted about wanting to buy a new carburetor for my 340 International. The consensus was for me to rebuild the carburetor that is on the tractor. The main problem I was having was a suspected leaky needle valve which caused to carburetor to flood while sitting. I did rebuild it, and it still has the same problem. Now what?

Click to expand...

Did you inspect the float for pinholes? Did you clean the new needle valve and seat before installing? Did you set the float to the specified height?

The float was fine. There wasn't any holes in it. I set the float height at 1/4" as the instructions prescribed.

Paul from MI · Sep 18, 2015

Make sure your new gaskets don't cover the bowl vent. Carb will flood if the bowl isn't vented.

J.Wondergem · Sep 18, 2015

Also check were the needle seat screws in for a crack in the threads.

Wayne in MN · Sep 18, 2015

Make sure the needle is not too tight inside the seat. I have had to file off the triangular sides to get enough clearance so the needle would not bind.

gab · Sep 18, 2015

I had that trouble with a tisco kit I put in my Super M, might set 6 or 8 hours and then drip, had it apart several times before I took a magnifying glass to it, they never finished machining the seat. The slow learner I am got another tisco kit, seat looked perfect, completely different from the first but the needle wouldn't go in unless you wanted to drive it in with bfh, another bad seat. Got my money back for that one and got a Walker kit, I think it was. Twice as much money but twice the kit too.

fixerupper · Sep 18, 2015

If everyone else's advice fails, start looking for some off the wall reasons for a leak. Maybe a crack in the carb where the seat screws in? Slight flaw in the gasket under the seat? How much sideways slop is in the float hinge? Too much wear in the hinge and the float can rub the inside of the float bowl. Take the top off the carb and hold it upside down with the float installed. Gravity will pull the float down and push the needle against the seat. While holding it that way slightly lift the float and feel for glitches or catches. The slightest catch in float movement will cause it to not push the needle all of the way into the seat. Get out the magnifying glass and take a close look at things. Chances are you won't find anything that unusual but it doesn't hurt to take a peek.

BushogPapa · Sep 18, 2015

I find that Manual Fuel shut-offs are the Most reliable over anything else....

Ron..

IanC · Sep 19, 2015

Probably from rebuilding dozens of carbs and having it work to stop leaking. I may not have explained it well as I should have, but it WORKS. For those of you who have floated in both fresh water and sea water even though there is not much difference in the specific gravity you do float at different heights. I didn't tell him it was THE problem, just something to try.

L.Fure · Sep 19, 2015

(quoted from post at 05:05:10 09/19/15)
I find that Manual Fuel shut-offs are the Most reliable over anything else....

Ron..

That's what I had been doing before I decided to rebuild the carburetor. I may have to return to doing that until I can take the time to look at the carb again. You guy's have given me some goods leads to check in to. Thanks.

Royse · Sep 19, 2015

Are you sure it is the needle valve leaking?
There is a seal under the needle valve seat.
Make sure it is in good shape and that the seat is in TIGHT.
I have seen more than one leak under that seat.
Same symptoms as a leaking needle only slower to flood.

unc · Sep 20, 2015

(reply to post at 13:30:55 09/18/15) I don't know about the ihc carb, but the marvel schebler carb bodies have a tendency to warp in the center of the bowl. I put the top half on the surface grinder, to make it flat, and lap the bowl half on a surface plate. Make the gasket surfaces flat, and make sure the float is ok, and you would be amazed how many nagging problems go away. :?

Carburator Trouble.

Well-known Member

Well-known Member

Member

Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Similar threads