Chad,


I am not sure how old is your engine. Since the engine runs fine without heating up after starting, I assume the piston and liner still keeps the compression very well.

When I have problem starting an engine, I check following.

Glow plug if old & glow driver.

Fuel line including blowing air in to the pressure line to make sure the fuel is flowing well to carb.

Remove needle valve and make sure the carb does not have anything that prevent fuel flow problem. ( I carry canned compressed air with me)

Fuel tank check up. make sure the clunk is not stuck or plugged up. (Never happend to me since I use 3 fuel filters. one inside fuel jug, one on fuel pump, one on fuel line to carb). It is still possible to have something inside the fuel tank.

If you use dubro silicone inside your fuel jug or can, make sure that thing does not get hard. (happened to me while using higher nitro fuel) The blue fuel line got really stiff and brittle.
I didn't see this because, I never opened to fill the jug. I used pump to fill it. My fault.

Which version of 61 is it? If all the above are clean, remove & dis assemble the carb to clean. check for any build-up near the fuel nozzle.

Hope you nail the problem out.
Good Luck