LCGB Forums

After having starting problems recently, but I think that is sorted, I obviously hadn't changed the rings last year, and a new piston was bought, problem solved.
Anyway, it now starts and runs pretty well on the scootopia 22mm carb, apart from when you roll off the throttle and then accelerate again, there is a bit of a lag, and a cough before it picks up. I know there has been threads on this before, but can't find any.
Standard gp 200 engine, 22mm scootopia carb & Casa megaphone exhaust.

Paul

I would clean the jets out this time of year after being laid up. old fuel ?

New carb. Cheers for the answer though.

Could it be air screw?

Nigel. S wrote:Could it be air screw?

Don't think so, it ticks over OK.

Your pick up off of idle, or when deaccelerating, is governed by your slide ,pilot jet and air mixture screw .
The slight hesitation in pick up is due to the huge change in vacuum created when opening the throttle slide wide. The sudden increase in air flow lowers the vacuum which weakens the pilot mixture as the engine is turning over too slowly to create sufficient vacuum to draw enough fuel from the pilot circuit.
In normal operation the pilot circuit provides sufficient fuel to compensate for this.

It sounds like you are either getting too much air or too little fuel in your idle circuit. Too much air, due to an air leak, or your air mixture screw being too far out, or the wrong pilot jet or a partial blockage in your pilot circuit somewhere.

I'd check for obvious leaks first around the inlet first.Manifold to cylinder and carb to manifold. It only needs to be a minute air leak to ruin your fuel /air ratio.

If you twist the throttle slowly off idle,.... does the engine pick up smoothly without bogging or spluttering ?