warm starting issue
 

hey guys having an issue with my small block Chevrolet Merc cruiser. the motor runs fine but when you turn it off and try to restart its extremely hard cranking in almost doesn't turn over. But if I open the throttle blades and pump it twice it turns over perfectly fine. I think it may be vapor locking but not sure any help would be great thinking about getting a carb spacer

Thanks

Carbed engines don't vapor lock. The fuel may be evaporating or leaking out of the idle circuit though.
It could also be that the automatic choke is engaging.

Check the choke pulloff valve . Suck on the vacuum line attached to it then place your tongue over the hole and see if it holds . If not it needs to be replaced . Of course also check the vac line for any cracks . This is the mechanism that pulls the choke flap open slightly when the engine is cold so it can get some air to run . When you open the throttle to wfo there is a mechanical override that opens the choke flap slightly , that is why the engine sounds and cranks differently .

Hard cranking and not turning over would be unrelated to the carb. That would be a starter or electrical issue. Is that what you mean? Or does it turn over fine just not fire up?

How does opening the throttle and pumping twice mysteriously make it crank over just fine if it is a bad starter ? Reading between the lines I believe he meant it's hard to start or fire up . A little clearer explanation of the problem is in order .

My point precisely.