Li 150 won't start/run

[ianmoran]

Hello,

I've got a standard 1967 Spanish Li 150 which we just can't start. It was running when I bought it but it's laid up for a few months and now won't start.

We've changed the points, condenser , plug, HT cap, HT lead, coil, one item at a time, We get a spark but it won't do more than occasionally fire.

It was a bit low in compression, so new engine seals and piston rings have been installed.

The carburettor was cleaned and serviced. Fuel is reaching the carb and the plug gets wet but not soaked. Still won't start.

We tried another carb, same result. Swapped the stator and flywheel for other Li150 items. Still won't start.

Took it outside and set it on fire.

We didn't. An attempted bump start got a bit of smoke out of the exhaust and the hint of firing and running but that was all. We've used eezi start.

What next?

Any help welcome!

[MickYork]

Stale fuel ?
Did you take piston off ? if so it has it been put back the wrong way round ?

[Storkfoot]

A few thoughts:

Sometimes just renewing the piston rings won’t work, you may need a rebore.

The petrol has gone stale.

An original carburettor can fur up inside and just cleaning with carb cleaner won’t get to clean the inner drillings.

Did you check the timing by the way?

[Cgt75b]

Hi

A dry plug works wonders, try a soft plug like a BE6 just to get it running, oh and while the plug is out give it a dozen kicks to get rid of the excess fuel already int top end.

Good luck I hope this helps

Cgt75b

[missing lynx]

How many months has it been laid up? The fuel may have gone off

[ianmoran]

Thanks for the responses.

Piston checked. It's the correct way round.

We tried other, fresher fuel, bypassing the stuff in the tank.

We've tried 2 carburettors so far. Jets cleared with a compressor. The original carb was soda blasted as part of being serviced - new filter, float and seal.

[MickYork]

Maybe try a "Leak Down" test to help eliminate any potential leaks/lack of compression

A blocked exhaust could be another option

[hullygully]

Maybe try a "Leak Down" test to help eliminate any potential leaks/lack of compression

A blocked exhaust could be another option

+1

[Rich Oswald]

How many months has it been laid up? The fuel may have gone off

I've left scooters five or six months and never had a problem but you never know if it's E10.

Only thing not mentioned , is the choke working?

Rich'

[hullygully]

How many months has it been laid up? The fuel may have gone off

I've left scooters five or six months and never had a problem but you never know if it's E10.

Only thing not mentioned , is the choke working?

Rich'

+1 & try taking air hose off carb, if its choked up it'll start this way, or if having trouble with choke then do as mentioned but stick your mits over the carb opening when kicking off.

[ianmoran]

Thanks again for all the responses. We've checked the clearance between piston rings and barrel and it's within tolerance.

We haven't had the air hose on yet and have had a hand over the carb mouth when kicking it over.

Pressure test is the next thing for this. If it's not that, maybe we've got 2 duff stators. What are the odds?

Exhaust is new. Might put the original back on though.

[Storkfoot]

Have you checked the piston to bore clearance? Are there any signs of blow by on the piston?

[nickw]

If it's not that, maybe we've got 2 duff stators. What are the odds?

It's a Lambretta part

[hullygully]

points - did you put condensor wire back on in the correct position, so its not earthing out
did you clean the new points faces up cos in the past these used to have a laquer on them

[ianmoran]

Cheers,
Condenser wiring is good. We're getting a decent spark, before putting it in the cylinder head, points are opening when they should. Didn't know about the points faces thing.

[sunrisemac]

You can try a little squirt of oil down the plug hole to seal the rings then kick it over a couple of times before you put a clean dry plug in to try and start the motor.

[ianmoran]

Thanks again.

We've tried squirting eezi start in the carb but not oil in the head, so far.

I'm beginning to think it must be an electrical fault. Although the system produces a good spark outside the cylinder , what is the effect of putting the plug into the head on the functioning of the coil. We have tested 2 coils so far and they appear ok. There has been mention of a "collapsing spark" when it's under pressure in the head. Has anyone got any thoughts about this?

Or both fuel sources are so contaminated by water that they won't actually explode?

Fresh petrol is next on my list.

[tv175lambretta]

If there is a spark and fuel (wet plug), then by my thinking the next thing to look at is timing. Have you checked and are you sure you are doing it right (checked tdc and using correct direction)? Have you chacked woodruff key has not sheared and flywheel not moving on shaft?

[Cgt75b]

Try a different Cdi

[Rich Oswald]

Try a different Cdi

It's still on points so it has a coil and the op has tried two.