Shoddymill wrote:Thanks for this post. It appears the heater hoses are screwed up on my 72 hiboy. Have had a few problems since I purchased it last fall; the heater constantly blows heat and it starts really hard when the truck is hot. The weird thing is that after it sits for a few hours it starts immediately but if you shut it off and try to start it five minutes later you have to crank it over for about 30 seconds and pump the heck out of the pedal. Anyways, after looking at the schematic I found that the hose coming out of the back of the carb spacer is routed back to the front of the engine and it has a kink in it from the sharp bend. Does the coolant somehow cool the carb to prevent vapor lock? I'm planning to replace the hoses and relocate the tee back near the firewall like the schematic shows. Any other ideas? It is a stock 72 f250 hi boy with manual trans, Armstrong steering and a 360 with 16k miles.
Circulating coolant through the carb spacer is intended to prevent the carburetor from icing during cold weather and, to a degree, to reduce the amount of heat transfer to the carb when in hot weather. However, we all know the latter is more common than the former.
I think the best way to reduce vapor lock is to evacuate hot air out of the engine compartment, a phenolic carb spacer, and an insulated fuel line from the pump.
Your hard start problem is likely a leaky carb... namely a accelerator pump diaphram. It's probably draining the bowls and slowly flooding the engine. Only after the leaked fuel has evaporated will it start. That's my theory.
On the heater issue, your rig should have a shut-off valve. It's visible in the top pic.. middle left. It's also visible in the other pics. Check that it still has its gate valve (couldda corroded away) or the cable controller is disconnected or missing altogether.
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