Re-routed the fuel line, but still having warm start problems

[Schneiderman]

My 1970 duster with a 225 was having warm start problems so I re-routed the fuel line and relocated the fuel filter behind the alternator as I have seen suggested. But I still seem to be having the same problems. I might be a little better. The car starts and runs perfectly fine when cold. If I drive it around, park it for a little while, and start it while it's still warm, it will be hard to start, and it will run like crap for a few minutes. It even stalls sometimes.

Since I got the car last year I've replaced the air filter, spark plugs and wires, rotor and cap. What do you think might be causing warm start problems? I still have not done timing or a valve adjustment (I don't use the car much and I haven't found time to do these yet). I don't know if that has anything to do with my warm start problem. The car runs fine otherwise. In fact I was surprised to find today that after 178 miles of driving in a mix of highway and city with heavy traffic and some spirited driving, I got 21mpg- and that figure was arrived at after I filled up this morning then again this evening at the same exact fuel pump.

 

[805moparkid]

well timing and a valve adjustment will make a whole new motor...

do that and then come back to us...

well one thing is, is there a 1/2 inch or so wood/paper spacer under the carb?

 

[cudamark]

I suspect you're having a bit of fuel perculation causing a flooded condition on a hot start. I've never seen a slant 6 have a vapor lock problem since the fuel is on the opposite side of the engine bay from the exhaust. Make sure the heat riser isn't stuck. If it's ok, try adding a spacer under the carb to help insulate it from manifold heat. A stack of gaskets will work if you can't find a spacer but be carefull bolting the carb down so you don't overtighten and bend/break the carb mounting ears. The plastic (phenolic?) spacers work the best. You can tell if it's flooded by holding the throttle all the way to the floor while cranking the engine during one of it's problem times and see if it starts then. A high degree thermostat (195 or higher) will add to the heat problem too so I recommend nothing higher than a 180.

 

[slantsixdan]

Your carburetor needs attention. The float is almost certainly too heavy, being made out of foam and having absorbed gasoline. The inlet needle and seat are probably not sealing properly, too. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. Tune-up parts and technique suggestions in this thread.

(And yes, you need to have the correct 5/16"-thick insulator gasket between the carburetor and the intake manifold)

 

[Schneiderman]

There is a gasket under the carb, looks like about 1/4 thick to me. The carb probably could use a rebuild. So when I find the time I will rebuild the carb, replace the float, and do the timing and valves and see how it is then. Maybe next week.

Thanks for the help, guys.