Do all F-20's run rough without a load ?

Anonymous-0 · Jul 20, 2009

Have my 2nd F-20 that I have gone thru the engine. Head was rebuilt. 60psi wet/dry cylinder pressures. New points & condenser in mag. Under a medium or heavy load, it performs very well. Under a light/no load, it runs pretty roughly. This includes driving around the yard on easy ground.

Is this the nature of F-20's, or am I overlooking something?

Thanks guys !

Pete

Old-F20 · Jul 20, 2009

(quoted from post at 12:36:22 07/20/09) Have my 2nd F-20 that I have gone thru the engine. Head was rebuilt. 60psi wet/dry cylinder pressures. New points & condenser in mag. Under a medium or heavy load, it performs very well. Under a light/no load, it runs pretty roughly. This includes driving around the yard on easy ground.

Is this the nature of F-20's, or am I overlooking something?

Thanks guys !

Pete

all mine run smooth :?

Anonymous-0 · Jul 20, 2009

Great question! Most seem to idle rough. I would like to see them idle smoothly like an H. i hope forum members will enlighten us.

Andy Motteberg · Jul 20, 2009

Mine runs good under a load and sure has A LOT of power, but mine runs best idling fast because it has a plugged passage in the carb that I'm going to fix soon...
Farmall F 20 Idling
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Andy Motteberg · Jul 20, 2009

Another vid...
F 20
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Andy Motteberg · Jul 20, 2009

One more vid...
More videos

F 20 Cold Start
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Janicholson · Jul 20, 2009

The mags have no speed related advance mechanism. The impulse coupling is set to trip at TDC. When it starts and gets past the point where the impulse clicks, it goes to full advance. It does not like that at low speeds and idle. I would bet it would run much smoother if the timing was retarded to about 10 or so degrees at idle, but it is at full advance. It will over heat and make no power retarded this much, so it is not an option. Assuming the carb has been tweaked to best running, the only solution is to use a distributor with centrifugal advance. I would put a distributor on it when using it, and a mag when showing. Remember a mag is grounded to stop, and a distributor is shut off from the ignition voltage. If it is crank start only, it may not have a battery. Thus live with it. JimN

Anonymous-0 · Jul 20, 2009

My F12, 20s, and 30 all idle as good as a well-tuned H or M. I do have to back off of full spark advance, but only slightly, not so the exhaust gets throaty. My F series motors have had new valves and hardened valve seats, new valve springs, good hot mags, timed by the book, carbs cleaned out and adjusted according to the particular engine. When under load, it's full advance for max power.

Tom in Michigan · Jul 20, 2009

Pete, Try increasing the spark plug gap to .30 and see if it settles down. Tom

AJB450 · Jul 20, 2009

Pete,
When my dad bought a new F20 in 1939, the dealer told him to set the spark plug gap at .35 instead of .25 to make it idle better. This seems to help. Also helps to retard the spark a bit when idling. I just put a new manifold on my F20 and it seems to run very nice at idle now.
Al

Anonymous-0 · Jul 21, 2009

Yup, I do agree that retarding the spark does make it purr like a kitten. That is what we have been doing when just sitting or puttering around the yard some. I'll have to try opening up the spark plug gap to see what that does.

Thanks for sharing your experience!

Pete

RN · Jul 21, 2009

Like early Harleys the ignition advance/ground gap is manual, set ignition to 1/2 way when idling, low speed. Remember that stop position grounds mags, some early mags were fixed advanced. Adjustable load governors became available late 30s, a couple years before H and Ms were made with them.

IndianaRed · Jul 21, 2009

Careful! Thought you were gonna stick the camera right into the fan!!

Very nice, I've seen that one YouTube, and I'm envious. Nice running machine.

The F20 was my Granddad's first tractor, (used), bought it when he was 18 or 19 and still farming with his dad who I think had a 10-20 and some horses, would've been about 1938 as he was born in 1920. We just lost him in March. His F20 is in pieces, an Uncle started to overhaul 25 years ago and got no further than tearing down, then leaving it open to the elements. Gonna be a big job, but I told Grampa I'd bring her back to life. Might need to haul you down for some expert help.

Thanks for the vid, love hearing that ol' girl purr.

Bri

IndianaRed · Jul 21, 2009

LOL, what's that "sxxy brunette" doing in there with your tractor videos??? Better be careful, you know how some people are here.

(Nice though!)

Andy Motteberg · Jul 21, 2009

"what's that "sxxy brunette" doing in there with your tractor videos???"

What???????????????????????????????????????

IndianaRed · Jul 22, 2009

After playing your video, along the bottom it showed all your other videos. Play it, you'll see what I mean. There was one title, well, I won't even say, but I was surprised to see it in there. No big deal.

Andy Motteberg · Jul 22, 2009

YouTube puts those vids down there. Not all of them are related to my videos and they usually are not videos by the video owner. Any of the "crappy" stuff is probably just "Promoted" or "Featured" videos that YouTube will plaster all over anyone's videos.

IndianaRed · Jul 22, 2009

That's what I was thinking, but it seemed like they were all your vids and then there was just that one right in the middle of them. But ya, it must've been some YouTube thing. Again, no big deal, thought it seemed out of place.

Do all F-20's run rough without a load ?

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