I have to choke a little more than usual to get my challenger 1800 (1999) going sometimes, but it seems from the amount of smoke coming out of the back there's something else going on. I checked the rave valve, and actually pinch the two lines off from oil reservoir each time so it's not oil leaking in. I'm about to try and clean carbs but have no idea what I'm going to find when I open them up. Any ideas? The engines smoke for about 10 minutes after first starting them. I'm using the sythentic mototr oil too so it's not cheap oil or anything. Thanks for the help. Tom