If I let my motor sit for 7 days or so without running, then it takes a few attempts to <br />start it and it runs rough with serious missing. After 20 to 30 seconds it will gradually <br />rev up to normal (sounds like 1 cylinder at a time cleans up) then all is fine. No smoke <br />during all this, just rough. Usually takes lots of warm up throttle lever to keep it going,<br />it will be running rough, then will jump to next higher rpm level as the next cylinder <br />starts running cleanly.<br />-<br />If I let it sit just a few days then it starts fine, just turn the key, no warm up lever <br />needed.<br />-<br />After the hard start, the motor is fine, runs smooth, restarts are immediate even <br />hours later.<br />-<br />2000 model year (although bought new Dec 2001), F100, 4 carbs, 222 hours on it. First <br />owner did not run it often during his 8 months (30 hrs) of ownership but swears it <br />never did this. I typically do an hour or so at 3000 to 4000 rpm, then a few hours at <br />1200rpm, then the 4000 rpm for an hour again.<br />-<br />I have tried new spark plugs with no improvement, always run a fuel stabilizer (Stabil <br />for first 150 hrs, PRI-G since), have filter/water separator, tried running carbs dry <br />before storage, running carbs about half empty and leaving carbs full, tried fuel <br />system cleaner. This is an old problem, first noticed it at 50 hrs or so and is very <br />predictable.<br /><br />Any ideas?
