Crash Bang Wallop, Nightmare PART 2

[Muttley McLadd]

Could it be an electrical problem?

[soulboy]

Could it be an electrical problem?

that helped

[Knowledge]

I think the fuel starvation may be the answer, on the other scooters i have built, I used a fast flow fuel tap. On this one i have kept the original tap and it sits slightly lower than the fast flow tap.

Might you overcome the problem of starvation by filling the tank to the top. This provides a good head of fuel to keep the carb supplied. When the level of fuel in the tank gets low, there can be insifficent head to allow the carb to run correctly, so it runs lean and revs.

Ultimately, keeping the tank constantly topped-up is not a great way to enjoy your scooter, so a diaphram fuel pump might need to be employed. However, in the short term, brimming the tank might provide some clues.

[GLscoot]

Yes, I do agree. I think the fuel starvation has been the cause. I built the second engine perfectly. All nuts tightened and used gasket paste on all joints.
I have built 6 of these and never had a problem, they were all PX engines. This one is an LML engine, with the large manifold and the proper reeds, I did introduce the Pinasco Flytech Stator but that should not make a difference to the general running of the engine and the engine starts to scream as soon as I go up the hill on my street. So I do believe its fuel related. I am changing the fuel tap at some point today. I won't turn the engine over until I can fit a kill switch.
Cheers

[GLscoot]

Before I start the engine. I did notice a little wear and tear on the crank section of the engine casings. This should not affect the crank in anyway, should it.

[GLscoot]

As for pictures there on my other post Vespa Winter Project.

[GLscoot]

Finally got to the bottom of my problems, the LML engine had a hair line fracture which got progressively worse, for obvious reasons this caused the massive air leak. I changed the engine for one I know was ok, this was a PX engine. This also started to rev its nuts off, so decided to check over all the components and notice the throttle cable had snapped a few strands around where the cable elbow enters the carburettor, this most definitely caused the throttle to stay open as it was a nightmare to remove. Along with fuel starvation, due to the original fuel tap sitting lower than my other project and made worse when travelling up hill.
I am now going through the progress of fitting a different LML engine with reed block and changing the fuel tap with a fast flow tap, should have it ready by the weekend all things going well. Thanks for your help.

[ArmandTanzarian]

Good luck. You must have been close to dropping a match in the tank!