250 inliner trouble shooting

[stringbean25]

i have a slight stumble off the bottom end at an idle, right when i touch the throttle i cuts out like its gona die but if i bump the throttle hard so it stumbles the motor kinda hickups and the rpms will jump up. The motor runs good above 1200rpms its just not below that but it idles good

I had the carb rebuilt (rochester 1bl monojet)
tomorrow i'm gona drop in a napa reman distributor
good plugs and wires i replaced those last year
i set the timing about 8 degrees it runs the best for now right there
i run mid grade with my lead additive

this what i've done so far, next to doing a compression check
can anyone with inline love help a young buck out

thanks

[68gmsee]

There's several causes for stumbling so it's probably going to be an Easter egg approach. You've done the preliminaries which is to make sure your ignition components are good. Here's some other things I've done:

Insure there's no vacuum leaks.

Check timing and maybe advance it to see if it improves the problem.

Insure vacuum advance is working, holds a vacuum and not leaking. Move the vacuum advance to engine vacuum. (lower connection on the carb.)

Make sure fuel pump and filters are good.

One other thing -I like a slightly higher rpm on idle so I adjust it so it's somewhat higher than what the book calls for. It helps with stumbling on my truck.

[Wrenchbender Ret]

I like all Msee's sugestions. If that doesnt get it check the linkage from the throttle lever to the accel. pump rod. You may have to take the top off the carb & raise the float level & check the metering rod adjustment possibly raiseing it a little.