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