365GT problem

Assuming 1967 365 2+2 from your profile. ?Single/Dual Distributor?

Do you have or need the Owner's Manual? I have the 1968 OM which has a good picture and description of the fuse box but doesn't state it's exact location. From it's appearance, I'd guess it's inside the car as opposed to the engine compartment. Also judging from the 1970 diagram it would be in the cabin, passenger side firewall.

I don't have finished wiring diagrams earlier than 1973 (http://www.ferrari308gtbi.com/Wiring512.php) but from the 1968 OM there isn't much to the engine electricals that varies from any other car of that year. What happens when you try to start a hot engine? Click click click from starter or no fuel? Clues?

 

There are two quarter turn buttons under the glove box that open the drop down panel to expose the fuse boxes.

Tom Kizer

 

Sounds more like a vapor lock or fuel pressure problem to me......a failing fuel pump might act that way....

I agree a fuse is either 'good' or 'blown'....no relation to the engine temp or conditions...examine it though as the fuel pump fuse wire terminals have been known to melt and fail to clamp the fuse tightly....

 

I would agree on the vapor lock.
The cure for it is either making sure your fuel line does not get hot from running next to something hot, such as the exhaust pipe, or by using an electric fuel pump, placed somewhere near the fuel tank that is able to push the fuel forward to the engine no matter if the fuel is warm and there are vapor bubbles in it.
If you already have an electric fuel pump, then you need to check the fuel filter in the tank or nearby the fuel suction in the tank: chances are it is clogged.

 

Does the car crank? Got spark? got fuel? Need more info. If the dealer cant find the fuse box find another dealer. Mike

 

Some of the models of that era had both mechanical and electrical fuel pumps. Starting from cold you switch on the ignition and electric pump and wait 15 or 20 seconds, then crank the engine to start. I can see that parking the car with a hot engine will probably boil out much of the fuel in the carbs, and probably vapor lock the mechanical pump. Just switch on the electric pump to overcome both problems. See if you have one and make sure it works if you do. This assumes that when you have your starting problem, the engine is cranking over with the starter at a normal speed.

 

This seems like a possibility -- I've seem something similar with a 330GT that has similar electric/mechanical pump setup. When I start it from cold (running the electric for 20 seconds before cranking and then shutting off the electric pump after it starts) it will run for an hour on the mechanical pump with no issues. However, if I park it after driving for a while, and then start it up several minutes later, it runs fine but after a few minutes starts to starve for fuel and then I've needed to turn on the electric pump to assist. I'm thinking there is some vapor lock causing it because mechanical pump works fine until after I shut it off hot. Maybe you are seeing a more severe version of this condition so it doesn't run at all once hot. Are you turning on the electric pump when trying to start it after it's hot?

 

+1 on vapor block.
+1 on fuel line reroute if near heat sources.
Does the electic pumps have integral check valves?
My understanding is that fuel can't vaporize if the pressure doesn't bleed off.