Brief Hesitation When Full Throttle Applied

[Hal the Elder]

Hey Y'all...

First, let me say that Oscar has never run better!

Yesterday we crested Wadena Hill at 30 MPH...the best performance ever!

However, there's the minor irritation of "stumbling" for about one second when I'm cruising at moderate throttle and suddenly open it wide. After the brief hesitation, full power returns and everything is Jake.

Is this because the carburetor has no accellerator pump (like an automobile carburetor) to squirt a jet of gas into the intake to instantly handle the wide-open throttle?

My 22mm carb has been modified to the following configuration:

Restrictor plate opened to match the port opening.

82mm Main Jet replaced the stock 90mm jet.

Needle clip placed in 4th groove.

My elevation is 3000 ft. where the atmospheric pressure is only 13.16 PSI.

Thanks...
HAL & OSCAR

 

[RdKryton]

Hal
You still have 2 grooves that you can try on the needle. Try the 5th groove first and if that makes it worse try the 3rd.

Jim

 

[bill green]

Hi Hal With what you have done your next step is to advance your ignition plate. This make the throddle control more agressive and in my case got ride of low end hesitation..Hope this helps..Bill

 

[Hal the Elder]

HEY BILL:

My throttle response is instantaneous and snappy! It's only when I go suddenly from part throttle to full throttle that the engine says "who, me?" for one second and then recovers.

I would think that the problem is carb-related.

Thanks...
HAL

 

[bill green]

Hi hal for the most part thats a fairly normal thing..It did help to advance my ignition to about 26 DEG.....Bill

 

[Hal the Elder]

HEY JIM:

With the needle clip in the 5th groove, it makes it worse...and it also sucks the tank dry with only 7 revolutions of the flywheel!

AND THIS IS WITH A SMALLER MAIN JET!

Will try the 3rd groove next.

HAL

 

[RdKryton]

lol Hal
That's funny. Go to the middle groove this time. Good luck.

Jim

 

[Hal the Elder]

HEY JIM:

The 3rd groove was the charm!

Now I get good full-throttle response whether roll-on or snap-on!

HAL

 

[RdKryton]

Glad to hear it.
Have fun.

Jim

 

[bill green]

Hi Hal Very Cool ..Have fun..Bill