GP150 Problems - runs with choke on, high revving...

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Northener
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Main scooter: Lambretta SX200
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I have a compeletley bog standard Italian GP150, starts within a couple of kicks, initially it would only run with the choke on.

Since then I have stripped the engine & put new drive side seal, inner mag seal (left the outer one in place), fitted new rings as others badly worn, new head gasket, base gasket, inlet gasket, new exhaust plus new gasket, everything torqued up correctly, still only run with choke on so after a changing a worn slide everything thing appeared fine on a test run. I thought fine then headed out on a trip & it stalled on low revs when stopping then had high revving & one occasion i could not turn it off with the ignition.

I have since checked the points (the gap correct) & put the timing to 19 degrees (was set at original standard 21), tried a different suppressor cap, checked the coil on a multimeter (it's fine) also cleaned connections.

Did have it running withot the choke on whilst it stood but now just stalls each time i turn choke on, adjusted the air mixture screw but know engine really need sto be warm to set up.

I did notice the pink wire on the stator that the outer pink was exposing the wire so taped that up & put a new sleave on the wires.

All lights/horn are fine.

Anyone any ideas on this?

Thanks
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garry inglis
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if you had it running with choke on your carb pilot jet must be lean and the choke has made up the difference then when running without choke its stalling also check manifold nuts are tight
Northener
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garry inglis wrote: Wed May 23, 2018 5:00 pm if you had it running with choke on your carb pilot jet must be lean and the choke has made up the difference then when running without choke its stalling also check manifold nuts are tight
Thanks, as i say it is a completely standard set so standard pilot jet, i've all standard jetting to it, i've since stripped & tried another 22m SH22 Dellorto & jetted accordingley with the same result.

Before i did any work on this when i got it i took it for an MOT & it ran fine going about 4 mile then on return it would only run with the choke on (been same since but not used on the road), i've since carried out the work above as it was an import & no idea of state of engine hence stripped it. Seamed ok for about 12 mile other day then played up.

I did make sure everything was tight but likely to go back over much of the work to try & rule things out.

I'm assuming it's one of the following:
Air leak
Carb problem
Electrical

????
Northener
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Posts: 39
Joined: Fri Jul 15, 2016 5:18 pm
Main scooter: Lambretta SX200
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UPDATE: Without tempting fate after trying two different pilot jets (of same size) which were both cleaned with blasting WD40 through the holes i tried another but this time i cleaned the top pin hole with some copper wire then WD40, not as though you can really see whether its blocked as it's that small (even looking through a magnifying glass), anyhow on kicking it up it idled fine with no choke on & sounded as it should i then took it on a 25 mile test run & all (at the moment) appears well.

So thanks Garry for mentioning the pilot jet.

If it plays up again i'll add some more info here.
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