Stumble on acceleration

[KMR54]

Hi,

I just picked up an 86 pickup with a 22r motor. The engine was recently "rebuilt" by the PO. The engine seems to have plenty of power but has a strong stumble at speed when you lightly press the accelerator. Strong acceleration causes no stumble and plenty of power. Any ideas on where to look first?

thanks

Ken

 

[KLF]

22R meaning it has a carb? Was it also rebuilt?

Might check the timing, also make sure the vacuum advance is working in the distributor.

 

[KMR54]

KLF,

Thanks for the quick reply. Yes it is carbed and I dont know if it was rebuilt. On inspection it looked very clean. I will check the vacuum advance and timing as you suggest.

Thanks
Ken

 

[Combat Chuck]

check the plugs and fuel filter before tearing into the carb.
I had a HUGE stumbling problem, and it turns out I had a hump-backed plug contact.
The Mule will also buck lightly at speeds when the Fuel filter's tired.

 

[KMR54]

CG,

Will do. The plugs and wires, disty, cap and rotor are new. Could be the fuel filter or a faulty wire/plug.

Ken

 

[KLF]

I have seen brand new plugs with cracked insulators, so they would short out and not properly spark.

 

[Combat Chuck]

Good luck!
The 22R's a pretty tough motor, and will nearly run on mud and not ping, but if something's wrong, it'll always let you know.

 

[KMR54]

update,

fixed the problem a few weeks ago. the vacuum line feeding the accelerator pump (not easily visible) was disconnected. Plugged it back in and NO BUCKING.