Hot start issue

BillK2632 said:

Type of fuel pump doesn’t matter - fuel in the line heats up and vaporizes and the pump can’t punp the vapor. Next time it happens pour cold water on the fuel lines to cool them down and see if it starts. I’ve had my engine vapor lock a few times.

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Got it. Would my fuel lines being metal have a positive or negative impact on this ?

Sean195 said:

Got it. Would my fuel lines being metal have a positive or negative impact on this ?

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In post #3 you say there is fuel leaking into the manifold after shut down.
The carburetor itself is too hot. You need to resolve this.

Do you have an insulating spacer on there now?

Was there one there before the replacement carb was installed?

Type of fuel line doesn't really affect vapor lock - you should have a metal like running from the fuel pump to the carburetor and a rubber line from the tank pickup > filter > pump. If this started after you installed the new/rebuilt carburetor, it has to be related to the carb setup/install. Like mentioned above, you have to have the spacer on the 4.3 mercarb setup. These engines are prone to carburetor / fuel / heat problems like vapor lock and run on. Spark plug type, idle and timing adjustments are very important - when adjusted properly they run great, but even the slightest out of adjustment can cause problems.

If you have the spacer it is is obvious, it's about 1/2" and sits on the intake and the carburetor sits on top of it. Look at the schematic here, #25. https://www.perfprotech.com/mercury.../9021/70?search=807726A2&sortpartnbr=807726A2