Fuel starvation?

[wack 63]

Could you have an air leak on the carb or airbox gasket? The choke is masking the fault by supplying extra fuel.

[rosscla]

I've had the carb all off and cleaned it out, don't see any sign of an issue with gaskets at the moment though might strip it all down and try some silicone on the reed block and box. I also shortened the fuel pipe as much as I could.

Was some speculation about the oilseal, see my problem in the other thread as the symptoms are a bit similar but I dumped some of the gear oil to check. Looks and smells like gear oil, no hint of petrol. Maybe if I take the read block off I might be able to get a view of the seal.

Have torqued the cylinder head again and had the exhaust off to try and stop it spitting black gunk all over the place from the split on the stub.

No major improvement and match abandoned due to a waterlogged pitch...

[Ginch]

I liked this tip so much I saved it... here it is again -

Block the exhaust with cloth and hand (should cut out).....if it still runs it's sucking air in through the main seal..

Not sure if he means flywheel or clutch, but clutch is pretty easy to test - take the breather out and plug it with your finger. It should make a difference to the idle if the seal is gone. I suppose to test it you could smear a blob of grease around the flywheel side seal and see if anything changes?

[rosscla]

Thanks, if it's ticking over on the choke and I block the exhaust it stops.

I'll try the breather and flywheel tips though.

[Livi- Graeme]

Standard carb? Check inside the fuel bowl. Look at the bottom two holes one feeds the choke the other feeds the jets. My mates had the same symptoms. The feed to the jets was blocked but his carb had been unused for a while. Just a suggestion

[rosscla]

Yes, SI24/24E open top type idle jet, LML reed casing, not sure of the origin of the carb box though it is autolube type. Autolube is disabled. I blew it all through with carb cleaner yesterday.

Will give it a check again cheers, soon as deluge ends.

Also going to silicone the reedblock and carb box.

[GLscoot]

Any joy.

[rosscla]

Quick update, was going to say progress report but that would be a big fat lie.

I stripped down the carb, carb box and reed block tonight. Gasket under the block looked a little shonky so replaced it and sealed the lot with silicone.

Sadly it's no better.

I'm thinking that if I want to go anywhere this weekend an engine transplant will be needed.


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[wack 63]

A mate had a similar problem as this when he broke down on the Skeg rally. After checking everything out it was the CDI pin that holds the HT lead had rusted away. It would start but then die when choke pushed in.

[rosscla]

It's about the only thing I haven't changed so far will give that a go when the missus calms down about the great dirty oil splodge on the flagstones...


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