Technical Throttle plate screws

[smart51]

I now have one beautiful clean carburettor thanks to me new ultrasonic cleaner. The screws that hold the throttle plate to the spindle were very tight to get out, very hard to get in and now they're in, they keep turning. I wonder if I've stripped the threads. Are they usually trouble?

 

[smart51]

Nope, the spindle is toast. I'll order a new one.

 

[bugsymike]

I think generally throttle plate screws are fitted then peined slightly one way or another to prevent them shaking loose, hence the damage on removal, so I tend to try not to disturb them.

 

[smart51]

I think generally throttle plate screws are fitted then peined slightly one way or another to prevent them shaking loose, hence the damage on removal, so I tend to try not to disturb them.

I wish I hadn't disturbed them. I only wanted to clean the carb casting. I did consider leaving it in place but decided on thoroughness. Ah, well.

 

[smart51]

Just to add to the frustration, I ordered a new throttle spindle, which arrived today. They've sent a 6.5mm one, rather than a standard 6mm. More days of waiting while a new replacement comes.

 

[bugsymike]

Just to add to the frustration, I ordered a new throttle spindle, which arrived today. They've sent a 6.5mm one, rather than a standard 6mm. More days of waiting while a new replacement comes.

Do they come with screws etc.? What was said re "peining them over or whatever they recommend , just out of interest?

 

[smart51]

Do they come with screws etc.? What was said re "peining them over or whatever they recommend , just out of interest?

It came complete, spindle, throttle plate, screws plus plastic washers (which my old one was missing) plus nut and spring washer at the end.

 

[smart51]

A second replacement throttle arrived today, from a different supplier. It too is 6.5mm in diameter. The one I've taken out is 6.0mm. The supplier offers 3 sizes: standard, +0.25 and +0.5. Given that the on I took out is 6mm, I'd assumed the oversize ones were 6.25 and 6.50. I'm beginning to wonder. What is the correct size of the throttle spindle on a 28IMB?

 

[Toshi 975]

Your post prompted me to dig out the original new old stock Weber 28IMB rebuild kit I have. It has the spindle that I measured.

 

[smart51]

Yours is exactly the same as the replacement I've had. Just by the threaded end is a shoulder that is 6mm in diameter. The rest is 6.5mm.

 

[smart51]

I've had yet another replacement spindle, this time from Webcon UK. This one fits. I've just had time to fit it to the carburettor, fit that to the car and start the engine. It runs. Tomorrow, I'll set the mixture and take it for a test drive. Fingers crossed.