Cold start after a long sit is wet and smoky

[RC92234]

Given the chilly weather, haven't had the car out much. Almost zero chance of freeze and there is still plenty of work to do, so not putting it away for winter. So it's probably been two cold weeks (high 30s for the low) since needing to start the car. When I did, started easily and runs mostly smooth at about 1000 rpm but the smoke! And lots of black wet out the tailpipes. I'm not sure what other diagnostics to report so feel free to ask away.

But from what I've read in other threads, it sounds like oil is getting into the combustion chamber and causing on startup the excess smoke and spit. What I don't understand is why only after it's set awhile and it's cold. This definitely doesn't happen if started again soon after (<1 to 2 hours later).

Thoughts?

 

[MikeGriese]

Worn valve guides, most likely. Oil gets past while the engine is not running.

 

[kcmash]

Black smoke is indicative of a rich fuel mixture. Blue smoke is oil, and white is antifreeze or water.

So if you have black smoke, you could have a choke that is hanging closed too long, or you could have a sticking needle in the carb. A lot of ethanol based fuels are not good on carburetors.

I suggest trying a fuel treatment, possibly SeaFoam, or another fuel treatment to see if that helps stop the smoking. Of course it will take a full tank to flush those through.

Definitely get some Stabil in the fuel system before storage. I have run mine for about an hour with Stabil, to make sure it got into the carb.

Kcmash

 

[bkdunha]

It is going to run rich with a cold start. Furthermore, if it has been cold out and the exhaust starts to warm up from the engine you will get a fair amount of condensation in the pipes and muffler. This condensation will pick up any of the unburnt black soot if it has been running rich for a while. The soot combined with the condensation blowing out will give you the black stuff behind the car. In my opinion not a big deal, but when you can check to see your mixture. Again, if it is cold it is going to run rich for start and until warmed. If you start the car often during the cold months you will get this black out the tailpipe. Fuel additive Stabil, Seafoam will help maintain the carb at start up. If you have access to non-ethanol gas definitely worth the investment during storage. Ethanol absorbs water and can make a mess of the entire fuel delivery system and carb during storage.