TEA20 governor...maybe ?

Couple of you-tube clips below of my TEA20 that I am not restoring, just looking to get it to some sort of running order.

It will sit and idle happily all day but when I bring the revs up to half and then full throttle it surges quite badly. I can push & hold the governor lever assembly with my hand it will rev freely throughout the range. I have turned in the bumper screw as far as I dare without any noticeable improvement.

The timing has been checked & the points set. The 24t is also set as per the manual

Am I going to have to remove the timing cover and have a look around ?

Any suggestions greatly appreciated

https://www.youtube.com/watch?v=wsjQR4BnRT8

https://www.youtube.com/watch?v=2yXlhHCG1fI&feature=em-upload_owner

Try partially choking it, see if the surging stops. If so, the main jet is set too lean, or restricted.

In case you have to inspect TIMING arrangement?

(1) 85 MM Bore Engine
(2) Front Lip Oil Seal "National /Federal Mogul Lip Seal" # 472164V A SMALL amount of BLUE Silicone was placed around the inside bore of the front timing chain cover before Lip seal was installed (3) I installed a repair SLEEVE on the front drive Pulley, make "DURA SLEEVE" # 99175. The sealing area were the LIP SEAL makes contact was slightly grooved. Dura Sleeve specs. 1.745">1.753" Diam. # 68 Rockwell Hardness
(4) On installation the Governor plunger shall be reseeded tight against the Flyweights and no weights shall be loose or hanging down.
(5) A small amount (only enough to make the surface shiny) of engine oil was added to the shaft of the governor PLUNGER as well as the timing chain.
(6)There are NO timing MARKES on the NEW Sprockets. You may whish to line the timing marks up (facing each other) before you remove the sprockets.
(7)Place the old sprocket (CAM SPROCKET) on top of the new sprockets and accurately scribe the new sprockets as to the timing marks. There are FOUR hols in the hub of the CAM SPROCKET. Keeping turning the old sprocket until the four hols and all teeth line up. These hols are slightly off set. I used several SHOULDERED cap screws to ensure I had the new and old sprockets properly aligned. You may have to flip the old sprocket over...see right up.
(8) It's good practise to measure the thickness of the hub of the old crankshaft sprocket and the new crankshaft sprocket as the teeth on the two sprockets should align for both proper operation and longevity.(there were shims between the old Crankshaft sprocket and the shoulder portion of the crankshaft)
Cheers
Bob...