Throttle hesitation

FrankS

Member
Tuned up a 901 Ford with new plugs, points, rotor, condenser, cap, & wires. Runs OK except for a momentary hesitation when I open the throttle. Owner tells me it wasn"t present before. The carb is a TSX 662 Marvel Schebler. I"m not familiar with this particular carb but would expect this to be normal since there is no accelerator pump. Is it? The power needle initial setting is 1- 1 1/4 turns but the tractor couldn"t pull itself up a small grade set at 1 1/4 and doesn"t reach max power until it"s about 2 turns. Again is this normal? Finally I can"t get a rich idle mixture by turning the idle screw in. My dwell meter fluctuates wildly so I"m not sure what RPM it"s idling at. Is the 400-450 RPM spec critical?
I"d appreciate any help from you Ford experts.
 
Normal adjustment is where it runs good, but you should not have had to adjust mixture after replacing electrical components.

You sure the points are gapped right and the screw is tight?

I assume you did not mess with the timing.
 
The carb setting had been messed with previously per the owner. Points are set at .025 and are tight. After tune up it randomly popped through the exhaust at idle and lacked power with main valve at slightly less than 1 1/2 turns. Timing looks OK but not sure of the idle speed because my old tach/dwell read erratically and the tach on the tractor doesn"t work. Again, it runs good except for the momentary hesitation when you hit the throttle.
 
I will open up the main valve until it will no longer stumble when I manually move the throttle from idle to full speed.
 
Does the dwell meter (wish I still had one of those!) fluctuate when checking the dwell? As in when bringing up the RPM? If so, that is an indication of worn distributor bushings.

Might recheck all the electric connections related to the points, condenser properly grounded, etc.
 
Point gap too wide. Set at 18 to get longer dwell. Sounds like you are getting barely enough dwell to run and meter should quit bouncing. Distributor bushing may be bad.
 
That is a good point someone brought up, I think .025 is plenty wide on point gap. I would set back at .020 and then re-time.
 
The specs on this website and from the dealer both have the point gap at .025. Note that this is not an 8N/9N.
 

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