Engine Cuts One Pot When Reved

[ddelectrical]

Hi. A little further with the detective work. I managed to seal all the ports on the carbs and put some low pressure air into them via the float bowl atmospheric pressure breather. Then sprayed soapy water over the outsides and there are no air leaks to the outside, (Thank you dablik). I did find, however, when blowing into the cold start fuel feed tube port that goes from the jet block in the float bowl up to the cold start plunger via the brass tube there is some air bypass on one carb. Putting a very small amount of pressure on the end of the cold start plunger stopped this. The plungers are new but there is still a very slight bleed through. There is a spare hole on the white plastic arm that slides the cold start bar across so I am thinking I will attach a light duty spring to this to pull the plungers fully shut and see what happens.

 

Reply to Bjorge: Yes, it will rev all the way if opening throttle slowly but will cut out on one cylinder when opening throttle quickly. It initially picks up from idle revs nicely but then looses it at higher RPM. 

 

And now I have cracked a carb top. Oh bugger. My bad.

 

Reply to Fixitstan: I am interested in the seal kit if available. I am located in Devon. Can we PM on here? Quite new to the forum. Cheers.