[Gary de Lima]

I am having trouble starting the engine if it sits for over 3 to 4 hrs (typically overnight)

If I squir some gas directly into the Caburator, it starts on the firat crank... and then will continue to start on subsequent tries... except if I let it sit for too long before re-starting.... any suggestions what to look for.

The engine does not have a fuel pump or boost fuel enricher. I believe a membrane in the Carb acts as the pump.

[triumph190]

If it has a primer bulb you might try replacing it. A common symptom of a primer bulb not working correctly is an engine that is hard to start after sitting for a prolonged time.
There is a check valve inside the primer bulb if it doesn't work correctly gas will leak back into tank.