hard start when engine warm

[Snappy]

My 73 Duster 318/904 with summit cam edelbrock carb and intake, MSD. My question is when cold pump the gas twice bump stater and she fires right Up, when I run to town and get back in to restart, I have to pump the gas or hold it to the floor and crank forever then when it fires up you can smell how rich the exhaust is. Any suggestions.

 

[krazykuda]

Have you checked the reluctor gap in the distributor. I had one that was at .030 " and would start cold and not hot sometimes. I put it back to spec. (around .010 or .007 with brass gauge) and never had a hot start issue again. This is the gap between the pick up and the 8 ribs on the distributor shaft.

 

[cudamark]

My 73 Duster 318/904 with summit cam edelbrock carb and intake, MSD. My question is when cold pump the gas twice bump stater and she fires right Up, when I run to town and get back in to restart, I have to pump the gas or hold it to the floor and crank forever then when it fires up you can smell how rich the exhaust is. Any suggestions.

Yeah, don't pump the gas! When you shut it down hot, there is a certain amount of perculation that will happen which will make a hot startup a slight flooded condition. Sometimes if you just turn the key without stepping on the gas at all, it will fire up. If it is a severe case, hold the throttle to the floor and it will lean out so it starts. To prevent that condition....make sure the carb is not leaking internally first. Check the float level and change the float valve if necessary. Next would be to reduce under hood temps with a 180 thermostat (if it's higher now), insulation or spacer under the carb, and timing set correctly. Naturally, the cooling system needs to be up to snuff also.

 

[Robb]

I greatly improved my hot start issue by adding a 1/2 inch carb spacer....

 

[Bulldozer]

as cudamark stated, and i have had many a problem, with a float sticking as well as hot fuel percolation with those carbs.

 

[Snappy]

Thanks guys, the carb spacer sounds good. I actually removed a steel separator plate sandwiched between two gaskets when I rebuilt the carb. As for timing, what is the proper setting. I set base timing at 10deg btdc when I installed the cam, and it didn't knock so I left it alone.