766 running rough

i have a 766 that is running ruff and poor throttle response. I checked the timing with the timing light and at idle it is at 18 degrees BTDC. In my IT manual it says i should be at 1 degree at low idle and 18 degrees at high idle no load. I adjusted the distributor to 1 degree at low idle and the tractor ran worse. I'm going to go through the carburetor, new plugs, points, condenser and rotor. the cap and plug wires look good. Is my distributor off somehow? i have never had it out. I did a compression check and all cylinders are with in 5 psi. They were hitting about 160 psi. any help or guidance will be awesome. thank you

Oh and one other thing here pull the plugs and take a look in at the cylinder walls and see how much scoring has taken place . See my post to your question on the other page This is a fuel related problem .

You st timing at 18 degrees at full throttle at rated RPM . It's not a carb problem it is not a fuel cap breather problem it is a fuel issue the reg gas of today is NOT the reg gas back then the minimum octane is 93 and again this is minim when this tractor was NEW reg gas for the most part was 95 octane and gas tractors ran just fine . fuel issue did not reall stat having and affect till we got into the eighty's . I don't care what the rest think about this as they do not make a living working on and tryen to figure out why this is happening there are three or four of us on here that made a living working on I H tractor and have at one time had every nut and bolt out of them . The things you need to know on a I H gas tractor is what fuel to use and what oil to use or you will learn the hard way why you don't use what you have been buying . We have run gas I H tractors for the last forty years or so and got along just fine as we learned the do's and don't . And at the present time we are NOT usen the gas tractors as we can no longer get the gas to run then on and i myself am tired or replacing piston and sleeves . Our last 706 gas ate the last piston running the haybine because of the gas . And that one had a C 291 in it . So let the bashing begin .

this tractor has a 291. My timing at low idle is 18 degrees BTDC. At high idle it is above 18 Degrees. My IT book says 1 degree at low idle and 18 degrees at high idle. Is this correct? I understand what your getting at about the gas we use today. The cylinder walls dont look too bad. Is my timing out of wack?

"too bad" is a purely subjective observation. Do you know what you're looking at/for?

On the timing, though, it sounds like your advance isn't working, or you're measuring the timing wrong.

Number 1 cylinder wall has a score mark. The others look like normal wear of the cylinder. I marked the flywheel at 1 and 18 degrees BTDC and
used a timimg light. hooked to cylinder number 1. Is that wrong? At low idle i had 18 degrees and high idle was above that.

I do not worry about the ideal timing once i get one up and running for the first time . I worry about what it is doing at rated RPM . Also what plugs ya running ?? NO hot heat range plugs . No champion . We have had good luck with Autolites and A/C .

there is a timing pointer on the front engine cover and timing marks on the crank pulley . sometimes they are hard to see but they are there . To make the 18 degree show up better i use a chisel and place a deeper groove at the 18 degree mark . If you have 18 degrees at ideal you are then running around 36 37 degrees at rated RPM and that is a NO NO . When you set timing on these get it running and let it warm up for a couple min. then put the throttle WIDE OPEN and then set for the 18 degrees . each time you change points you recheck the timing .

Ok. I put a new set of points in also new AC plugs. Hopefully get it running tomorrow ans set timing. I will report back. Thank you!

I installed new points, condenser, rotor, cap and spark plugs. All my plug wires checked out in good condition. I got the tractor running and warmed up. I set my timing at high idle to 18 degrees BDTC. Tractor runs a lot better. It seems when you give it more fuel quickly at idle the engine wants to fall on its face but it does recover. If your running above 700 rpm and give it fuel quickly it acts fine. It runs a lot better when its warmed up after going down the road a little while.

They're not running right if they aren't at least a little cold blooded when you first start them up. Learn to keep one hand on the steering wheel, one hand on the throttle, and one hand on the choke for the first 5-10 minutes and you'll be fine.