61' Farmall 560 Gas Timing

RyanS

New User
Hi Everyone,

This is my first post; however I've been using the site for years and it's been extremely helpful! Question, I have a 61' Farmall 560 gas and no matter if the engine is hot or cold, it idles rough - primarily periodic burps. I've replaced wires and plugs (Champion D21's) and no change. I adjusted the timing as well to 2 degrees on the "A" side when idling. If I give the tractor full throttle, the most I can get is 1000RPM's. At 1,000RPM's I'm at 10 degrees on the "A" side. It's my understanding I should be at 30 degrees on the "A" side when at 1900RPM (full throttle).

Questions
1) Why can't I get this up to 1900 RPM's?
2) Any ideas on the burping?

Carburetor? Or something else?

Thanks in advance!
Ryan
 
Pretty much all common gasoline engines start with the ignition timing AT or shortly AFTER TDC, (so they don't "kick back" and break your arm, or the starter), then advance to (typically) somewhere in the 20? to 35? BTDC range.

If your spark timing is on the "A" (after) TDC side when running you have some serious distributor/spark advance issues.
 
Pull distributor out I bet advance springs,weights and pins are shot.It needs a full rebuild meaning bushing,gears and all the rest.Get rid of those d21 plugs they are way to hot.You are asking for burnt valves intakes get to hot and she will burp thru carb.Valve lash needs checking.I bet they are to tight or can,t be set right because cam is wore out.If you are running d21s I bet she burns oil and needs rebuilding.the list goes on and on.Hopefully the Tractor Vet can chime in as he has forgot more than I can recall.Scott
 
Get rid of those d21 plugs they are way to hot.You are asking for burnt valves intakes get to hot and she will burp thru carb.

Oh, for gosh sakes, Scott, "hot" sparkplugs don't "burn" valves!



Next thing you're gonna say is "don't give 'er some high octane gas, she's gonna blow up" from all the extra POWER!!!
 
Well for one lets start with the carb to gov linkage and get it set , i am not going to go thru the whole thing as this evening i am tired one to ma three fingers of C/R to tyep out how ya scync a carb to gov. and as for timing to get it correct ya need full engine RPM . Then ya need to look at the throttle linkage , then the gov spring . Then ya ned to pull the point's plate out and look at the fly weights and springs in the gov. probably what your tractor needs is a Major tune up . and the big thing you need to do is BUY at least and I T manual and set down and READ on all the why fors and how comes . Next that the D 21's and throw them across the fence and get either a C 86 A ? C or a 386 autolite . Next make sure you have solid Copper ing. wires .. Next to avoid burning the exhaust valves you need to be running Case I H LOW ASH OIL in 30 weight . with out going out to the truck and looking up the timing on a 560 gas burner at 1:51 Am while under the al fulence of Ink oHol all i am goiing to say is it is inthe 23 to 25 Degree range at rated high ideal our in other words WIDE OPEN throttle . It would take me around three hours to make yours run like it was suppose to run. starting from square one . NO if your 560 is plum slap wore out due to extensive field testing then all bets are off.
 
I'd also like to comment on the spark plug heat range affecting the base engine....

The heat range simply is a relative gauge on how much heat the plug conducts away from the electrode.

The balance point is to find a plug which doesn't melt down the metal tips but stays unfouled by combustion byproducts. Otherwise said, more "heat" in the plug burns off the fouling products, but go too far into the heat range and the electrodes will melt down.

The basic spark though is unchanged, and as such the combustion event is unchanged by "heat range" of the spark plug.
 
To hot of spark plug can cause burnt valves,Been there done that.Ihc 221 thru 291 engines you will never melt spark plug electrodes they burn exhaust valve every time.As far as gas, high octane gas it burns cooler.From actual work on my farm I can tell you that as I have a 460,560 and 706 all gas hogs.Mine get little use anymore as non ethenol high octane gas avalibility is hit as miss from suppliers around here.So there is my answer to hot spark plugs from using those old girls.Scott
 
It sounds like that spark knock might be in effect if the requirement is high-octane fuel. That creates intense combustion heat from basically a mini explosion ahead of the flame front that could be enough that the exhaust valve can't handle it.

Imo, easiest fix is to retard timing very slightly. The spark advance (or retard) basically shifts combustion heat into the combustion chamber or else throws it down the exhaust pipe. Engines that have knock sensing use the advent of spark knock to retard spark timing. Engines that don't have knock sensing just have to be tuned so that in "open loop" the max advance won't cause this issue.

Other issues like the carbon coating in the combustion chamber as the engine ages can contribute to spark knock by blocking heat flow and also increasing the combustion ratio incrementally.

That said, I only have one 6 cylinder 460 tractor with 221cid and I haven't used it nearly hard enough to find out about any issues like this.
 

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