warm starting problem

[Mike - - Bristol]

I'm using the Lammy for work for a while and when I stop for a paper, about 12 miles,
the scooter will start but not pick up . Once it's going again it's fine and if it's left for a while it seems ok.
Cleaned the carb and the plug looks ok (little rich maybe) any Idea's guys ??
Oh starts ok from cold

[coaster]

Need a bit more info on your set up reallyt but if its standard then I'd look at your choke to make absolutely certain that ther rubber bit on the bottom of the plunger is sealing corectly. Also check the air filter. If it has a kit on it then this problem is fairlyt standard especially with larger carbs running through an air hose. The problem is due to spit back through the carb and causes fuel to gather in the bellows. When you stop for a short while the fuel gets sucked back in and the engine floods and won't pick up until it has burnt off. The work around is to turn you fuel tap off a short distance before you stop and leave it turned off when you re-start. A permanent cure may take some time to find and please let me know if you do

[Mike - - Bristol]

Need a bit more info on your set up really

yeah thought that after I posted,
Thanks Coaster
Mugello 186,
26mm Delorto
Ram air filter
Clubman (back on for now)

the plug was a bit on the rich side so I dropped the main jet to 100, it was the only thing I had in the garage to try.
On the way home I stopped and ended up stuck for about 20 mins starting every time and ticking over with me swearing at it
with an old guy watching me sat on a bench wondering what was going on .

[Timbo]

I'm no expert but the weather has definitly caused a problem to my open bell mouth.........

[bazman]

I'm no expert but the weather has definitly caused a problem to my open bell end.........

Soz fella

Mike Bristol is your ram-air filter mounted on carb or top of bellows?

[coaster]

Need a bit more info on your set up really

yeah thought that after I posted,
Thanks Coaster
Mugello 186,
26mm Delorto
Ram air filter
Clubman (back on for now)

the plug was a bit on the rich side so I dropped the main jet to 100, it was the only thing I had in the garage to try.
On the way home I stopped and ended up stuck for about 20 mins starting every time and ticking over with me swearing at it
with an old guy watching me sat on a bench wondering what was going on .

Mugellos are well known for warm starting issues, it would seem to be due to the port timeings. I would put the larger main jet back in, it WON'T be that as the main does not affect the starting although you could try a smaller idle jet depending on what's in there now.

If you get the problem again you could either whip the plug out, kick it over several times and then put the plug back in or take the filter hose off at which point it will probably start straight away but you will need to get the hose back on quickish unless your tickover is reliable. For warm starting my mugello on a warm start I turn the petrol off, lean the scoot to the left (off the stand) close the throttle (very important), give it a good kick still with the throttle closed and when it fires I open the throttle very carefully, sometimes it will catch and rev up but if it bogs I open the throttle all the way and hold it there. It will chug away for a minute or so (seems like eternity) but as the fuel goes down in the float bowl it will suddenly rev up at which point turn the fuel back on and away you go. I've been managing with the problem for over 4 years now

[sean brady scooters]

i hate to mention this yet again ...but a small (1mm ) drain hole in the bottom of the hose works wonders....

[storkfoot]

A permanent cure may take some time to find and please let me know if you do

Col, have you ever tried advancing your timing?

[Mike - - Bristol]

thanks guys.

Coaster
I know the main jet won't effect the starting but that was by the way, it seems better with the small main jet tho'
and it does seem to work flicking the petrol off so I think that is the prob.

bazman:
yeah , bellows

there was a short moment this morning when it looked like the same problem but cleared very quickly and stopped at the Post office on the way home
and it was fine when I left so as long as I remember to switch off the petrol it could solve it, might see if I have some small tubing to set up a drain off.

cheers again all.

Mike

[Chutney Brownlove]

Mike, take the filter off, it will be fine. I had a Mugello that wouldn't run when warm with a filter on no matter how much I down jetted it. However, the exhaust and inlet timing were a little long.