Aftermarket downhill only carburetors

[Dave G9N]

Edit:
Having cleaned and disassembled the original carburetor that was provided with the tractor, the following question about where to drill a hole does not make much sense. The Amazon reviewer did not adequately describe what he did. As JMOR pointer out, the only place where there seems to be a hole that might be in the wrong place appears to be the tiny vent holes in the side of the main nozzle.
End of edit.

My daughter bought a 2N with a brand new cheap carb that will cause the engine to stall when pointed uphill. I thought that it might be the oft mentioned sticky float, but could not see how that would cause this problem. I have seen a number of online forum questions about this. None of them ever got back to say whether any of the suggested fixes actually helped.

I read through a bunch of Amazon negative reviews about one of these carbs that mentioned the uphill problem. Finally, one of them said "i had to drill another hole lower in the bowl to let gas into the main jet when going up a hill. it would run great on the level before..." This seems to make sense to me. At least it would if I knew what to look for. I.e. where is this hole?

The engine starts immediately on the level, but not at all when pointed up a 5 incline. I have one of those Plastic mechanical inclinometers.

It is hard to accelerate in 3rd up even a shallow slope, which would cause the gas to slosh back in the carb. It also tends to surge on the level accelerating in 3rd with the Sherman in high range. It will run, but you can't start moving uphill at 5 and will die in a short distance at 10.

So is there a hole in the float bowl? Where is it? Where should the new hole be drilled? How big? How deep? Will I screw it up? (OK, yes to that one, but it's broke anyway).

If the hole needs to move less than ~1 hole diameter, do you plug it first? Would enlarging the hole for a short distance (assuming it slopes down) lower the entrance enough to do the trick?

This post was edited by Dave G9N on 07/17/2023 at 04:26 pm.

 

[Eman85]

"My daughter bought a 2N with a brand new cheap carb"
Red Flag of course the question is why did they change the carb? Could possibly be because of this problem.
First how much fuel is in the tank? How much are you opening the fuel shutoff valve? Have you done a fuel flow test? Shut the fuel valve and remove the plug on the bottom of the float bowl and drain the carb. Open the fuel valve and let the fuel flow into a pint jar and see how long to fill it and report back.
Engines never seem to stall going downhill as it doesn't require and power, gravity takes over. You might just have a fuel starvation problem. Could be as simple as the tank vent clogged or the main jet out of adjustment.

Call the previous owner and ask for any and all parts they took off.

 

[JMOR]

(quoted from post at 13:55:38 07/12/23) My daughter bought a 2N with a brand new cheap carb that will cause the engine to stall when pointed uphill. I thought that it might be the oft mentioned sticky float, but could not see how that would cause this problem. I have seen a number of online forum questions about this. None of them ever got back to say whether any of the suggested fixes actually helped.

I read through a bunch of Amazon negative reviews about one of these carbs that mentioned the uphill problem. Finally, one of them said "i had to drill another hole lower in the bowl to let gas into the main jet when going up a hill. it would run great on the level before..." This seems to make sense to me. At least it would if I knew what to look for. I.e. where is this hole?

The engine starts immediately on the level, but not at all when pointed up a 5 incline. I have one of those Plastic mechanical inclinometers.

It is hard to accelerate in 3rd up even a shallow slope, which would cause the gas to slosh back in the carb. It also tends to surge on the level accelerating in 3rd with the Sherman in high range. It will run, but you can't start moving uphill at 5 and will die in a short distance at 10.

So is there a hole in the float bowl? Where is it? Where should the new hole be drilled? How big? How deep? Will I screw it up? (OK, yes to that one, but it's broke anyway).

If the hole needs to move less than ~1 hole diameter, do you plug it first? Would enlarging the hole for a short distance (assuming it slopes down) lower the entrance enough to do the trick?

ole on other side just like this one, but the fuel level is much higher at only 1/4 " below top of bowl casting.

there was a story about the nozzle holes being in wrong locations as well.

This post was edited by JMOR on 07/12/2023 at 02:28 pm.

 

[soaked]

Hi Dave G9N,
JMOR has posted this pic many times. Its a great tool.

Suggest rig one up to see the fuel level.

My aluminum carb circa 2018 has a 1/8 BSP thread.

Wonder if the level is too high due to up and down play on the float hinge. If so, bend the float arm to increase the 1/4 spec, to about 1/2 inch out on the float's toe. Should compensate for the slop, and lower the level to the proper height.

 

[Dave G9N]

Thanks everyone, the sight glass is brilliant. It sounds like there may be a solution. The most logical place to drill holes seems to be the nozzle. I'll have a look inside and maybe try the nozzle from the rebuild kit.

Red flag? Agreed. The seller replaced the battery and distributor too, saying they were cheaper to replace than rebuild. Suffice it to say that I think he finds old tractors that won't run and flips them for a few hundred bucks profit on craigslist. The old cast iron carb came with the tractor. It was rusted up solid. Took forever to free up the choke. We will try to clean it up and rebuild it.

No flow test yet. It pulls a 2 bottom plow on level surfaces no problem, so I think it does get enough fuel on a level surface. If you back down a hill it still wants to die -- and take you with it. It will start right up on the level, never pointed up on a slope.