The Stovebolt Site Forums The Parking Lot '60-'66 Trucks 63 gmc hard hot start

1963 gmc 2500 series 305e stock everything except air cleaner. Ive checked, cleaned and adjusted sparkplugs to 035. Points set at 016, dwell at 30, timing at 10 btdc. Carb has been apart twice. Nice and clean, float set to spec. Runs smoothly. Cold start, pull choke, 2 pumps, fires right up. Push choke in 2/3rds. Let warma tad, choke in and drive. No problem. After driving abit, say half hour. Nice and hot, gauge at 165 or so. Let sit half hour and like clockwork. Hard start. Crank for ever then gets going but no chain of events. Tried with choke, no choke, pumps, no pumps. Cant get it figured out. At least not yet. Any suggestions?.?

Try no choke and hold your accelerator to the floor.🛠

Thanks. Will try it and keep ya posted.

I think I read that when cold, it starts right up. I think I read when hot it Does start after much cranking.

Seems like; Loss of fuel flow, needs to regain. One quick way to find out something is carry a squirt bottle of gas. After heat up and no start, squirt some down carb, run back and start. If it fires right away, it's not electric or heat riser stuck.

So take off cap next. Next drive, take off gas cap.
Still won't start unless gas is squirted down carb? See 3 and 5.

1. Heat soak? Doubt it. That motor has supper cooling features. 165 is low.
2. Heat riser sticking? Yes could be heating/boiling gas from carb.
3. Fuel pump? Yes
4. Gas cap not venting? Yes
5. Rubber fuel hose collapse? Yes
6. Coil and/or condenser? Maybe

I have a 305E also.

Thanks also. I was thinking coil also? I actually have a spare on the seat. Lol. Heat riser welded open. New fuel pump, all lines, tank, cap and filter. Not that something there isnt failing but somewhat unlikely. Ill try the cap and squirt bottle technique after i try WOT previously suggested. Ill keep ya posted.

Hi,
Maybe you have a float bowl problem. Sounds like it's starving for gas after start up when already warm.

Either that or you float just needs to be adjusted.

Good luck

Ok well heres what i got. Put about 100 miles on today. Not a hiccup. But it was warmer than ive ever driven the truck and it actually got to 175 degrees. Atad warmer than the previously 165, but all good. The other day i tried to get the same hard start effect but couldnt duplicate it. So i thought id be proactive and do something. I change the coil and cleaned the connections, which were needed. But was not the fix. After a heat soak, and attempted start. Nogo. I didnt do anything but hit the key, crank, no start. Stop crank, went to WOT, crank and started. Duplicated this act a couple times today. So i guess we have a winner. Thanks Justhorsenround. Not to mention all other input. If something else changes, ill update. But i think we nailed it.

👍🏻