263 Gas Motor Missing

My 706 gas 263 motor i think is missing. She fires up everytime without any problems, but when she idols and/or run wide open, it just sounds like she is missing. I changed plugs and clean the air filter...any ideas? thanks

Figure out if the miss is one particular cylinder.

Do a compression check.

Check the valve clearance. Hal
PS: The Tractor vet that posts on here has said numerous times you need to use 93 octane gas in these tractors. He has several.

93 octane yes but if he has a miss due to a melted piston, switching to 93 octane will not "heal" the tractor.

(quoted from post at 11:54:08 04/17/12) My 706 gas 263 motor i think is missing. She fires up everytime without any problems, but when she idols and/or run wide open, it just sounds like she is missing. I changed plugs and clean the air filter...any ideas? thanks

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Do a full tune up. Spark plug wires, distributor cap, rotor, points, and condensor. Might even want to replace the ignition coil, and even though you already changed the spark plugs, don't rule out the possibility that new plugs might not be up to snuff. Also, ignition problems will quite often mimic fuel related problems, and vice-versa, so make sure the carburetor is not set too lean.

Unless you are running that tractor full out, making it work as hard as it can, it will run just fine on the same gasoline that you use in everything else.

Rustyfarmall's advice is right on! But here's one more possibility: Check for worn distributor bushings.

Radial play in in the shaft at the breaker cam greater than a couple thousandths makes ignition timing erratic. And this will cause random missing, loss of power, increased fuel consumption, etc.

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I had similar problems with an IHC pickup (304 V8). Replacing badly worn distributor bushings made it run like new.

Have you had a timing lite on it yet ??? timing is set to full advance at wide open throttle and IF and again i said IF it is a 263 then it is set at 23 degrees BTDC . NOW IF by chance someone upgraded it sometime in the past to a 291 then the timing gets set at 18 degrees BTDC. . The best spark plugs to run in them are either a 386 autolite or a C86 A/C i have had less problems from them. Pull the valve cover and run the valves they set at .027 , No here pay close attention to the rocker arm as there will be a wear pattern and you do not want to get the feeler gauge on the high spot as you will NOT get a good valve set. as long as the engine is warm (anything over 70 degrees the .027 will be fine. Now as far as carb adjustment there should be NONE for load as there Should be a solenoid on that carb for shutdown only . Now some of the vary first one did have a screw on the back side and that SHOULD be five full turns off the seat with the key in the OFF . and the use of 93 octane gas is a must on these engines. Now some on here will say that you don't need to buy the high test But they are not the ones that have ever worked a 460-560 504 -856 -766 706 . TRUST ME they will seize a piston or pistons so fast you will not know it happened till it is to late and the damage is done . We still work ours in the fields. Myself i have had 706 gassers since 1982 of my own and not counting the ones that i bought and sold since 1985 .

He's got a burnt valve vet, done heard it before.

Pull the plugs and do a compression check first. A tune-up won't fix a burned valve or scored piston.

Well if he has a burnt valve then that was caused by not running low ash oil . don't care what oil ya run as long as it is a low ash . That lesson was hard learned once we switched to the low ash no more valve problems . Don't care how bad it burns the oil as long as it is the low ash they don't burn valves. Today i learned that one of my old customers went back to the cheap oil and guess what i have to go pull the head on his 460 gasser cause he burnt a exhaust valve while grinding feed today . said it sputtered and went to missing He told me that he switched because the low ash was to expensive . The valve job will cost him more then what he could have bought a thirty gallon barrel for.

Here is a cool video about IH oils, and the importance of using low ash in gas engines. (if my link does not post, go to youtube and search International Harvester oils)
IH Oils

Well guess what Old Bill told me way back was true and that is why we no longer have a valve problem as that is what we have been running for the last twentyfive years . Now all we need now is GOOD GAS and all my problems will go away. And John boys lastest deal with going to a cheaper oil and a oil change and now burnt valve in his 460 as of yesterday proves my point with him again. I'll have to show him this this morning as soon as he is done in the barn here in about and hour and a half.