Ruby throttle hesitation.

[morrisminor]

None at all, still works well but not keen on starting in this hot weather, what size fibre washers ?

[John Mason]

I had simlar problem with my Mk1 Ruby in that it would not slow run and altering the slow running jet made no difference at all wherever I turned it to. I also had the feathering condition you described together with the choke making things slightly easier and not cutting out when trying to increase revs with the accelorater. I solved this problem by cleaning out the jet that is behind the blanking screw you describe. The purpose of this jet is to allow a small amount of air to bypass the throttle butterfly when closed and allow the engine to slow run. I then found that I could adjust things with the slow running jet. This small jet is very difficult to remove and it is better to clean in place rather than removing it. By the look of your photo someone has tried to remove it and damaged it.

John Mason

[Pricey]

Hello John

The aperture in the damaged jet is free but I was thinking that it should obviously be deeper than it is now creating a different flow.
Your experience with this jet makes me think this is the culprit... If I am able to retrieve the remnants of the jet is a replacement available or do I need another carb body? 

Thanks for everbodys help so far.

Cheers

Dave

[John Mason]

The answer to your question about a new replacement jet is honestly I don't know. Try our cherished suppliers and if that fails try and go for a second hand carb.

John Masons

[John Mason]

For carburettor parts try Burlem Ltd. they are on the Webb I am sure they will have what you want,

John Mason

[Pricey]

Hello John

Tried them last week and got the below reply
---------------------------------------------------------------------------------------
"The progression jet 3345/50 is sadly no longer available new from us.
You may find some companies have new old stock utilising the part number.

Sorry not to be able to help further.

Kind regards.


Andy Barlow
Customer Services Advisor

Burlen Limited - The SU and AMAL Carburettor Companies
Spitfire House, Castle Road, Salisbury, Wiltshire. SP1 3SA
Tel: +44 (0)1722 412500   Fax: +44 (0)1722 334221   Email:"
------------------------------------------------------------------------------------------------------------

.....So if anyone has a spare carb body only which still has the progression jet in position let me know.

In the mean time I'll keep searching.

Cheers

Dave

[Ian Williams]

It looks to me as though your professionally rebuilt carb has been bead blasted, makes me wonder if some media has got stuck in the internal drillings connecting to the progression jet.

[Pricey]

It looks to me as though your professionally rebuilt carb has been bead blasted, makes me wonder if some media has got stuck in the internal drillings connecting to the progression jet.

Hello Ian.

No I can't find an obstruction. I have used a fine nylon brush strand and compressed air.

The progression jet is clearly mashed up and I doubt what is left could have any effect other than to dump too much air into the mix.

Still on the hunt for either a jet or a used carb body.

[Ruairidh Dunford]

Steve Hodgson will be able to help you with a replacement jet to try, cone back if you do not have his details.

[Pricey]

Steve Hodgson will be able to help you with a replacement jet to try, cone back if you do not have his details.

It was Steve Hodgson who refurbished it. I'll try him but I'd made an assumption that he would have changed it at the time if he had them in stock.