Diagnose Rough Running Engine

[Ben Hastings]

So, I've just been through some electrical work and finally got my '52 8n back to running.

This time, some things that were happening last summer seem more pronounced. The engine has always hesitated going up a hill (and I use that term loosely - our land is basically flat) and it's long been giving a sputtering sort of sound. In lieu of incorrectly trying to describe the quality of the sound, I used current technology to record a short video. It's linked in this post, so give it a listen and let me know if this is something you've heard before and have a good solution.

I did just replace the carb, the voltage regulator, the ignition switch, the coil, the plugs (Autolite 437s), the condenser and points. It was the last two that got it to start.

Gas is flowing fine from the drain plug (all screens were replaced last year and I checked them all in the last month for cleanliness). I have to give it a lot of choke to start.

I'm not sure where to begin, but any help is appreciated!
Video of the tractor

 

[JMOR]

(quoted from post at 18:29:55 04/27/11) So, I've just been through some electrical work and finally got my '52 8n back to running.

This time, some things that were happening last summer seem more pronounced. The engine has always hesitated going up a hill (and I use that term loosely - our land is basically flat) and it's long been giving a sputtering sort of sound. In lieu of incorrectly trying to describe the quality of the sound, I used current technology to record a short video. It's linked in this post, so give it a listen and let me know if this is something you've heard before and have a good solution.

I did just replace the carb, the voltage regulator, the ignition switch, the coil, the plugs (Autolite 437s), the condenser and points. It was the last two that got it to start.

Gas is flowing fine from the drain plug (all screens were replaced last year and I checked them all in the last month for cleanliness). I have to give it a lot of choke to start.

I'm not sure where to begin, but any help is appreciated!
Video of the tractor

ave you tried adjusting the Main Power Adjust needle (front) to see if you can smooth it any?

 

[Billybuck]

Sounds like you may have water in the fuel to me. Drain a pint or so in a glass container from the carb plug to look for separation or plumb a container of known clean fuel to the carb and see how she runs.

 

[Ben Hastings]

The gas should be good. I wanted to rule out water
and i drained the tank and put in fresh fuel.

I'll give the main power needle some adjustment
(tomorrow if we get a moment without rain!) and see
if that helps.

 

[weaveman]

Be sure the seal that goes around the butterfly rod is actually sealing. It's hard to control the air fuel mixture if air is coming in there. Also, is the manifold sealed tight? A leaking manifold will cause all sorts of spits and sputters. New spark plug wires? The points set right? And finally, when was the last time you adjusted your valves?

 

[Ben Hastings]

Adjusted valves? This tractor is older than my dad and I've only worked on fuel injected systems - some fairly deep stuff, but never getting IN the engine. The spark plug wires aren't yet a year old, and I believe the points (new this week) are set correctly.

I know other things have been relatively easy here, but I don't know where to begin adjusting the valves.

In other news - adjusting the main jet on the carb made a BIG difference. I don't have to keep the throttle all the way up to keep it from dying. It's still sputtering at idle and some while just driving. Maybe I need to adjust the valves - any help on where to start?

 

[Eriklane]

Any chance you have a leaking exhaust gasket? I found that my tractor ran like crap due to that - probably due to intake leaks? But, I replaced it and fixed it pronto...