Question on power and ignition advance on an F-20

Tom Fleming · Jul 29, 2008

i am taking my F-20 to an antique tractor show and pull on Sat, then to the county fair Sunday. I have tuned her up as best I can, and wanted to understand how best to advance the timing while I am pulling. At full throttle, should I use full advance? Should i adjust the advance as the load increases? Should i keep adjusting the timing as the pull progresses to keep the engine in it's "sweet spot" from a sound perspective?

Also, this will be my first pull, and I have been watching carefully, as I certainly understand that a good pull is as much the operator as it is the tractor. I have seen lots of letter Farmalls pull, but not any of the F series.

i don't expect to place in the antique pulls, but would like to make a respectable showing.

Inquiring minds want to know. 8)

Anonymous-0 · Jul 29, 2008

Tom,
If the impulse is working, full advance from the start sets the
timing where the engine is meant to run. Ours are set so you
retard timing "a bit" so they don't kick back while starting, after
starting;fully advanced. Mostly have fun.

PeavyTx · Jul 30, 2008

Tom

The old F-20 may surprise you. I pull with a 36 F-20 in 4500 lb class and she's hard to beat. I think tire pressure is critical. I like about 10 lbs. Win or lose you WILL have fun. Good luck. Peavy

Tom Fleming · Jul 31, 2008

Thanks for the replies. I do have one more question on the timing and advance.

At full throttle and full advance with no load, there is an occasional "miss", and pop. When I am at full throttle, and at about 3/4 advance, the engine purrs like a kitten. I have not been able to do a load test at full advance yet to see if the engine smooths out under load.

I have the timing set so that the center of the rotor is pointed at number 1 on the cap for TDC. However, there are "leads" on the rotor. At TDC should the timing be set to the beginning of the rotor contact lead, or to the center of the rotor contact. Just to clarify, the brass contact on the rotor as you know is a "T", so do I set the timing for the center, or the beginning of the lead. I know we are only talking 1 bolt hole on the coupler, but that can make a difference when trying to get full power.

I am also debating on the gasoline. I run 89 octane in all my vehicles, so I just fill my gas can with that when I fill up my truck. Should I be running 87 in this or is the 89 ok, or am I splitting hairs.

Question on power and ignition advance on an F-20

Tom Fleming

Well-known Member

Anonymous-0

Well-known Member

PeavyTx

Member

Tom Fleming

Well-known Member

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