Engine stalling when you give it too much throttle on take off

[skyman2112]

Carbureted engine, PCM 351 BOSS. So far tried rebuilding original carb, then purchased another factory style carb, then replaced fuel pump and then replaced the factory ignition and finally, got a completely different brand new holley carb. Nothing every changed, Stalls when you give it too much throttle from a stand still. In cruise, accelerates fine when you give it full throttle. You can see the accelerator pump working too. Really going crazy with this one. thinking vacuum leak maybe PCV valve?

 

[kenny nunez]

Have someone watch the secondary butterfly linkage when you punch it. The linkage should not move until the engine starts to turn up. If it does move try to restrict it and see if does not bog or stumble.

 

[skyman2112]

Have someone watch the secondary butterfly linkage when you punch it. The linkage should not move until the engine starts to turn up. If it does move try to restrict it and see if does not bog or stumble.

I have not checked that cause we tried 3 different carbs with the same problem, but its worth a look. Thanks

 

[Grub54891]

Have you checked the weights inside the distributor? Sometimes they get sticky or the springs break.

 

[Scott Danforth]

have you check that the accelerator pump actually squirts when you advance the throttle?

 

[jimmbo]

Carbureted engine, PCM 351 BOSS. So far tried rebuilding original carb, then purchased another factory style carb, then replaced fuel pump and then replaced the factory ignition and finally, got a completely different brand new holley carb. Nothing every changed, Stalls when you give it too much throttle from a stand still. In cruise, accelerates fine when you give it full throttle. You can see the accelerator pump working too. Really going crazy with this one. thinking vacuum leak maybe PCV valve?

When you say "give it too much Throttle from a standstill", does that refer to how quickly you give it Throttle, or how much Throttle you give it?
Does the Stall happen the moment the extra Throttle is given, or a few seconds later?
When you "replaced the factory Ignition System", what parts were replaced?

Since the Carb, had been rebuild, and replaced twice, it is difficult to blame it.

Being a PCM Engine I will assume the Spark Advance is controlled by the Computer, not by a Mechanical Advance in the Distributor. Have you verified that the Timing does advance?

What about the Fuel Lines between the Tank, the Fuel Pump, and the Carb? Sometimes a blockage, can allow plenty of Fuel at a relatively constant flow, but chokes when there a sudden increase in demand.
Fuel Filter?
When accelerating from a standstill, the Bow of the Boat Rises, maybe that causes a change where Fuel is not able to be delivered. At speed, the bow doesn't leap up, when more power is added