48 A Carb questions again

[sick48a]

Well I am having carb problems again with my 48 A. I thought I fixed it after lowering float to 1/2 in.

It runs good. I can push the brakes as hard as I can and it will run under load perfect. I can pop the clutch in 4th gear and it does fine. Starts good, idles good. Runs good under load with the bushog behind it. I start to go up a fairly steep hill and it coughs and pops and black smokes. What is the problem? Thanks.

 

[F-I-T]

Debris around the nozzle/chamber?

 

[sick48a]

Its weird though that I can work it to death on flat land and it run fine. Then I can drive up a steep hill with no load on it just riding around and it will cough and pop and black smoke, does the same thing with the mower behind it goin up hill. Does it no other time. I can get on the road in 6th gear and smash on the brakes until I choke it out and it will run fine.

 

[Mike N Mo]

My guess would be that the float sticks/binds when off level. Check for excessive play around the pivot pin. Just a thought......Mike

 

[Bob Harvey]

'Nother thot, maybe increase the float level to 5/8" or more. I have NO idea what it is supposed to be. HTH

 

[PopinJohn]

Perhaps you said earlier Magneto or distributor?
If distributor ignition, I would look for a loose wire or a wire shorting out when going uphill.
Or something like the battery sliding around in the box and a loose bolt on the ground strap.
If magneto, the coil could be loose on the coil bar, sliding to one side going uphill causing a short.
Pardon my rambling, I"m just trying to come up with ideas since you have posted about this before.
You said it black smokes when this happens which makes me think it isn"t fuel, but ignition.

 

[sick48a]

Thanks for the help everybody. Before this problem I had a problem with flooding out when I hit bumps so I solved that problem by changing float level from 3/8 to 1/2.
I still had this other problem previously also.

I also have thought maybe on hills the needle is binding in the seat. I will check that.

I will also check for loose wires. This tractor has a distributer. New points and condensor. New spark plugs and wires. New battery cables and ends. I need to get a new distributer cap for it and I may go ahead and replace the coil.

 

[DONMYEIL]

Have you tried a differnent set of plugs. Doesnt sound like they want to burn the extra fuel when the governer opens the carb. Check the throttle linkage for binding as well. Could the load needle be opened too much? Abt 1.5 turns or so should do it.

 

[Anonymous-0]

Going from memory here but didn't those have a brass insert "baffle" of sorts in the fuel bowl vent passageway? The vent being a hole in the main body towards the left rear of the fuel bowl about 3/8" in diameter.

Is it possible your baffle is missing and under up hill loads it is gulping fuel through this passageway as the fuel rises in the back of the bowl? Could this be aggravated by a fuel bowl gasket that is maybe leaking air in?

Either something like this or the float is loose on the pivot pin or sticking when not on the level like someone else said. Cant see why else it would run great on the level but blow black smoke when going up hill.

Ignition problems won't change the mix to a smokey over rich condition. Electrical misfire (mag or dist) would just fail to light 'er up at the right time making it pop, bark & burn fuel in the manifold and stack but it would still be a normal lean mix not a smoky rich one.

Hope you find this one!

 

[teddy52food]

Did you do anything to the carb yet? I worked on a 70 that acted wierd & when I took off the carb, I found out that the choke screws were gone. Sometimes the choke plate would close up & flood it out.It would do it when pulling hard in high going uphill.

 

[sick48a]

I am running Brand new autolite plugs. I can load the tractor down as much as possible and choke it out on flat land and it never misses a beat. It will pop cough and black smoke going up a hill even without a load on it. Load needle is only open about 1 turn.

I have took carb apart. The baffle is in there. I used new gaskets when going back together with it. Carb was professionally rebuilt by Burreys about 3 years ago.


I can turn the load screw in to the point that the tractor starts running horrible under load and it will still pop cough and black smoke going up a hill.

 

[sick48a]

I want to mention this again to make sure everyone seen it and read it.

One float went bad somehow it developed a lot of cracks. I put in a new float and set it to 3/8. When I first did this the problem was the tractor would flood and cough when I hit bumps in the field. So I set the float to 1/2 and got rid of that problem. Now I am dealing with the problem I have now.