LCGB Forums

Funny one this, having problems starting from cold (overnight) will not start unless I put my hand over the carb mouth to start, carb is 30mm Dellorto open mouth which is new, choke is working, thought I had cured this with a 55 pilot jet, checked the stator wires and the green/white is showing 445 would this be a factor, as it should be 520, can`t think of anything else, nothing obviously wrong apart from stator, when warm it runs and starts ok. Almost beaten me.

445 ohms is well with in the range of acceptable if it's an Indian stator but very poor if it's a BGM. Having said that, I doubt if the strength of the spark is an issue if it starts with a hand over the carb. Your problem is most likely choke related, you don't give many details i.e. what carb and other jets, timing etc, for a started, what size choke jet is fitted?[url][/url]

choke jet is 70 pilot 55 not sure of others as the scoot is a mates and its at his house, the choke is definitely working,

Could be an air leak ? This would cause poor cold starting. May not be an issue when running if you have unknowingly over jetted to compensate.

Hand over the carb is just cutting out air (and significantly richening the mix) so you are either too weak on the choke jet or there's an air leak.

The problem you have is you have a huge open venturi with no filter restriction, so the vacuum created by the engine when kicking it over is really low so the engine is going to struggle to draw sufficiently rich fuel mixture from the Atomiser to start from cold.
This is why bigger is not always better in terms of CV throat diameter particularly if there is no air filter.
Putting an even larger pilot jet in is unlikely to solve the problem because once the engine is warmed up its going to have too much fuel to idle properly and will probably hesitate on opening the throttle

If putting your hand over the inlet gets it started and you have a good performance otherwise then you probably have a good compromise with your current set up otherwise I would try a 26mm carb

I've had exactly the same problem on my Avanti'd s2, same carb, 70 choke, 54 pilot. Only last week I purchased a 75 choke jet thinking this would cure it, however before fitting it I checked my air/fuel mixture screw, which on mine is the one toward the back of the carb (a little flush screw head, not the larger knurled throttle stop screw), and discovered it was only 1 & 1/4 turns out. Ron Moss suggests 1 & 1/2 to 2 turns out, so I set it at 1 & 1/2 and from stone cold it started 1st kick!
All I'd suggest is that you try it, seeing as it's the easiest thing to try.

There is one caveat to this however, in that it now seems harder to start when hot...................Lammies, don't you just love 'em?

I should have added, I think on a PHBH Delly (the one i've got anyway, which I described in the last post), screwing out richens the mixture, which would make sense regarding having to put your hand over the carb.
Just out of interest, I think the opposite is true on Mk2 Amal's?