8n sputters and dies when on a hill

[Kenbob44]

I have a 1948 8n with 12volt upgrade and front distributer, new wires and harness and a rebuilt carb. Tractor starts just fine and purrs like a kitten. When i start to drive and an incline is encountered it begins to back fire and sputter. This happens whether going up hill or down hill. it even does it when on flat ground but leaning to one side. Checked all the filters in the system and all are clear. Any suggestions on where to start thge troubleshooting process?

Thanks,

Kenbob44

 

[Tim PloughNman Daley RIP]

I have a 1948 8n with 12volt upgrade and front distributer, new wires and harness and a rebuilt carb. Tractor starts just fine and purrs like a kitten. When i start to drive and an incline is encountered it begins to back fire and sputter. This happens whether going up hill or down hill. it even does it when on flat ground but leaning to one side. Checked all the filters in the system and all are clear. Any suggestions on where to start thge troubleshooting process?

Thanks,

Kenbob44

HiYa Ken, welcome aboard the YT Board. You need to get into the GOVERNOR and FUEL. Power gets increased thru the GOV on uphill slopes and as a load increases thrust on the engine. Do you have the Essential Manuals? OP MANUAL to start as a chapter on GOV in there and how to adjust. You'll need to R&R the unit first with a rebuild - kit sold here. The GOV has four 5/8" steel balls that wear out and need replacing. You may need to rebuild the carb too but one step at a time. If running OK now, leave it alone. You then make tweaks as required using the Throttle Linkage to GOV per manual instructions. Testing done under load by applying brakes and increasing throttle at the same time. You'll need a buddy to walk along and make the tweaks on GOV. Takes a few tries. SEE PIX for 8N GOV chapter, copy and save, print out if you need them.

Your Mileage May Vary,
Tim Daley (MI)

 

[Dober_paw]

Could there be an issue with the carb float hanging up when tractor isn't flat & level?

 

[Tim PloughNman Daley RIP]

Could there be an issue with the carb float hanging up when tractor isn't flat & level?

Paw = yes, possible but when he gets into the system part of the R&R'g will be the carb inspection. A stuck float will almost always show up with a fuel leak at the carb throat rubber hose to air cleaner connector. Worth investigating for sure...

Tim

 

[Roger in Iowa]

I have a 1948 8n with 12volt upgrade and front distributer, new wires and harness and a rebuilt carb. Tractor starts just fine and purrs like a kitten. When i start to drive and an incline is encountered it begins to back fire and sputter. This happens whether going up hill or down hill. it even does it when on flat ground but leaning to one side. Checked all the filters in the system and all are clear. Any suggestions on where to start thge troubleshooting process?

Thanks,

Kenbob44

Take the carb apart. Inspect the float
It may be partially crushed or have fluid, gas? In one or both tanks. Had similar problems with my 8n. Cause was high fuel level caused by crushed tank. Compressed air applied to needle valve holes can crush a float tank.

 

[Eman85]

Did the tractor have any problems before any work was done? Might be the human factor. Start with the dreaded fuel flow test.

 

[Kenbob44]

Thanks for the tips.. Will try them out this weekend.

 

[Tim PloughNman Daley RIP]

Take the carb apart. Inspect the float
It may be partially crushed or have fluid, gas? In one or both tanks. Had similar problems with my 8n. Cause was high fuel level caused by crushed tank. Compressed air applied to needle valve holes can crush a float tank.

I agree with not using compressed air on the float. The Float is brass and made in two halves, soldered together. Some solder joints can come undone and thus leak fuel. OEM parts not so much a problem but the new aftermarket stuff isn't always the best. Always perform the Fuel Flow Test first before you just start yanking parts off willy-nilly and guessing as to the root cause problem. It's easy, relatively fast, and will tell you if there is carb issue. Removing the carb and R&R'g a rebuild is the last step.

Tim Daley (MI)

 

[Dean]

I have a 1948 8n with 12volt upgrade and front distributer, new wires and harness and a rebuilt carb. Tractor starts just fine and purrs like a kitten. When i start to drive and an incline is encountered it begins to back fire and sputter. This happens whether going up hill or down hill. it even does it when on flat ground but leaning to one side. Checked all the filters in the system and all are clear. Any suggestions on where to start thge troubleshooting process?

Thanks,

Kenbob44

Check float level and float drop adjustment.

 

[Jim L WA]

The fact that it does that up hill, down hill or sideways would have nothing to do with the governor. I think everything points to the float.

 

[Tim PloughNman Daley RIP]

The fact that it does that up hill, down hill or sideways would have nothing to do with the governor. I think everything points to the float.

Really Jim? When uphill/under load the gov kicks in to maintain engine speed...FYI

Respectfully,
Tim Daley (MI)

 

[Jim L WA]

Really Jim? When uphill/under load the gov kicks in to maintain engine speed...FYI

Respectfully,
Tim Daley (MI)

Really Tim? What does the governor do when going down hill, to cause sputtering and backfire?

 

[Tim PloughNman Daley RIP]

Really Tim? What does the governor do when going down hill, to cause sputtering and backfire?

DO YOUR HOMEWORK

 

[Dan]

Kenbob - pretty sure your issue is a leaking float which has already been suggested. To verify, easiest way I have found is take it out and shake it right next to your ear - you can tell right off if liquid is inside. That gets missed a lot of times on carb rebuilds. Replace it.

My post is more about trouble shooting on these old tractors. They are very simplistic really. Your original post said you experienced backfire and stuttering. As a general rule on combustion engines that means either timing is off, or too much fuel is getting dumped into the engine and igniting in the hot exhaust pipe. Since you state it starts and purrs fine, that would eliminate timing. With this in mind, it points you to the air/fuel mixture.

Always evaluate and keep it simple and it will save you quite a bit of time and frustration finding the source of your issues. Of course, there are lots of great people here that can assist if you get stumped.

Good luck