Rough running unstyled G

[msteinblock]

Looking for some help with my 1939 G that runs super rough.

I have done the following and no notifiable changes

New wires
New plugs (tried both W18 and 3076)
New mag (also tested on another G that runs perfect)
New carb (also tested on another G runs perfect)
Air cleaner off
Re-timed Mag
Adjusted the carb everywhich way to China.
Fresh gas

What am I missing? I am starting to go crazy, I cant seem to figure this one out.

Thanks for the help!

 

[Watthour]

I see the governor hunting all over. If you manually override the governor and hold the throttle in a fixed position, what happens? Does is lean out and die? Go fat rich and choke?

The answer(s) might be a hint about the cause(s).

 

[msteinblock]

I see the governor hunting all over. If you manually override the governor and hold the throttle in a fixed position, what happens? Does is lean out and die? Go fat rich and choke?

The answer(s) might be a hint about the cause(s).

Thanks for the reply!

It stops "hunting" but still doesn't run right. It will not die or choke out. I can take a video showing that tomorrow, its too dark tonight.

I should have mentioned. I haven't tested this year, but a year or two ago I had it at a show and had it belted up to the fan. When loaded it just purred along and didn't miss a beat. It was running otherwise the same as shown today in the video. I need to load it up and see if it still runs like that under load. (I assume it does, nothing has changed) The last time I ran it hard I was plowing and it did OK, however if it did miss it had a really hard time recovering.

 

[Fixingfarmer]

What’s the status of the manifold and its gaskets carb to manifold manifold to head any cracks? Known fresh gaskets? Just about every one I’ve seen a studs broke or gasket is shot. If it doesn’t choke off it’s getting air from somewhere

 

[msteinblock]

Thanks for the reply. Known good gasket from carb to manifold, obviously would have replaced it when swapping carbs. I did peek at it on the way out the door this morning. I dont see any obvious manifold studs broke, but I do see what may look like that gasket has maybe failed. Symptoms would make sense. Boy...that's not a fun project.

 

[Fixingfarmer]

Ether can sprayed where you think the failure was will tell you if there’s an issue. Around the throttle shaft of the carb is another area but if the other g the carb came from was running well that’s probably fine or fine enough

Best to verify first as you are correct this will be a project I have pulled a b manifold off with the head without removing the hood fuel tank or fan shaft to get to that manifold all that’s extra is a head gasket and draining the coolant but the g I pulled everything off the top. Pain in the butt. You could do the same thing as a b but it’s alot heavier easier with a scissor table cart. slide it forward remove a couple head studs turn the head sideways and drop through the frame. It’s how I did pull the g head anyway even with the manifold and coolant pipe off.

 

[msteinblock]

I tried the ether trick tonight, it actually did not do what I was expecting. It did not "take off" or show any difference in engine speed. It did however show where there was a leak of exhaust coming out. I guessing the extra air is actually exhaust leaking into the intake side of the manifold via the bad gasket? That would kinda make sense as every once in a while I can it air coming back thru the carb....kinda like a back fire but not sounding like a backfire. I am guessing this is going to be a manifold job. A lot of work for such a "small" issue. Thanks again for the help all!

 

[rockcreek4630]

Looking for some help with my 1939 G that runs super rough.

I have done the following and no notifiable changes

New wires
New plugs (tried both W18 and 3076)
New mag (also tested on another G that runs perfect)
New carb (also tested on another G runs perfect)
Air cleaner off
Re-timed Mag
Adjusted the carb everywhich way to China.
Fresh gas

What am I missing? I am starting to go crazy, I cant seem to figure this one out.

Thanks for the help!

Have you adjusted the throttle rod from the gov to the carburetor.

 

[55 50 Ron]

Looking for some help with my 1939 G that runs super rough.

I have done the following and no notifiable changes

New wires
New plugs (tried both W18 and 3076)
New mag (also tested on another G that runs perfect)
New carb (also tested on another G runs perfect)
Air cleaner off
Re-timed Mag
Adjusted the carb everywhich way to China.
Fresh gas

What am I missing? I am starting to go crazy, I cant seem to figure this one out.

Thanks for the help!

sounds pretty darn good to me based on those videos. They don't have to run like a sewing machine to be considered good.

 

[rustred]

Looking for some help with my 1939 G that runs super rough.

I have done the following and no notifiable changes

New wires
New plugs (tried both W18 and 3076)
New mag (also tested on another G that runs perfect)
New carb (also tested on another G runs perfect)
Air cleaner off
Re-timed Mag
Adjusted the carb everywhich way to China.
Fresh gas

What am I missing? I am starting to go crazy, I cant seem to figure this one out.

Thanks for the help!

Have u pulled one plug wire off at a time to see if it will run on one cylinder. ? Are the valves set correctly? And have u checked the compression is the first thing to check !

 

[rustred]

Have u pulled one plug wire off at a time to see if it will run on one cylinder. ? Are the valves set correctly? And have u checked the compression is the first thing to check !

And and also post a pic of them plugs so I can see how they are burning ? I bet all black and fouled. And also working it on a load is a good think to do. Then check your plugs again. There now u got work to do.

 

[adediesel]

geez, i hope you find out what is wrong with that fine running engine.