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| Joined: | 03-12-2005 |
| Location: | Kingman, Arizona USA |
| Posts: | 532 |
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Other things I'd check, just to be CERTAIN:
1. What is your points gap? Should be 0.014" to 0.016". If it gets much beyond these limits the engine will run poorly. Did you lubricate the fiber arm on the points recently? These can wear down very quickly if not lubricated -- 0.001" per 100 miles perhaps.
2. Are all spark plugs in good shape, with good wires, installed tightly, and on correct plugs? A common error is to wire up the dist. cap backwards which has the same effect as swapping the plug wires for cyls 2 and 3; engine will usually run, poorly, on 2 cyls.
3. Observe the vacuum valves (pistons) inside carbs while working the throttle. Do both pistons go up and down the same amount and at the same rate, every single time the throttle is blipped? If not, either the carbs are out of balance, need rebuild, or there is something wrong (burrs, rust, etc.) inside. With the engine off, does each piston give about the same resistance when being lifted by a finger, and does it return all the way down when released?
4. How about air flow balance between the two carbs? Do you have a Unisyn or something similar to check this?
5. Are both carb mixture needles the same? Are the needles adjusted to give the right fuel/air mix? If in doubt, pull the vacuum valves out and set the needles to the 'datum' point, which is where the little washer at the top of the needle is precisely flush with the bottom of the vacuum valve. Put the carb back together and rotate the mixture adjuster 1/6 turn CLOCKwise, this will normally give you a very slightly rich mixture. You do need the special adjuster tool to do this.
6. Is the compression decent and roughly the same on each cylinder?