Running too rich

[dudload]

Hello all!

Still getting to work on the second Morris resto job. Completed the overhaul of the brake and clutch linkeage today, so thanks for everyone's help there!

Next up is the carb, as the car is running very rich all the time. I've checked that the choke isn't stuck on by manually opening it up and resetting on the carb and screwed the auditing nut all the way to the top = still black soot coming out the exhaust.

Next step, took the carb apart, cleaned everything, no notches on the needle, piston goes back with a nice clunk. Still runs rich despite screwing all the way to the top.

Any thoughts, would a new jet, needle, or bottom assembly help?

[philthehill]

Have you checked that the fuel level in the float chamber is correct?

[dudload]

Hi Phil,

No, didn't check the float assembly as no sign of overloading with the fuel pump constantly ticking. I didn't realise there was any adjustment possible in there (only been in to clean out gunk that was causing starvation in the other car) what should I be looking for?

[philthehill]

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[dudload]

Thanks Phil, now to to find a 5/16 round bar!

[philthehill]

Use the non fluted end of a 5/16" drill.

[dudload]

Thanks again Phil.

I took the carb off and apart to follow the burlem website on su recentering. After following instructions it gives a good clunk at top and bottom of adjustment.

However, this was sitting on the top of the jet I think as it fell out when removing the jet. I can't see on any diagrams (this is an hd carb as on a 1098). Could this have been causing the problems?

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[philthehill]

Can you post an 45 degree angle view please as I am having difficulty identifying the item.
Phil

[dudload]

Sure

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[dudload]

I've also taken the float lid off, but reading the workshop manual Phil, I assume I should follow the other diagram that calls for a 1/8 gap between the lip and float though as it's a 1098?

Also, whilst trying to confirm engine size I was interested to see that there isn't an engine plate in the usual place! Do you know a way of tracking this down?

[philthehill]

http://sucarb.co.uk/technical-hs-type-c ... djustments
I know you stated the wksp manual but what manual did you find the 1/8" float clearance in as in the link above it states 5/16". See also reference to fuel height in the jet. The carb fitted to the 1098cc engine should be a HS2.
Looking at the above link there is nothing that springs right out at me but it could be the top of the jet sleeve.
The block casting number is sure way of determining the block cubic capacity. The block casting number can be found cast into the block just below the rear tappet chest cover. The casting number should be 12A497.

[dudload]

Edit, duplicate post

[dudload]

Hi Phil, it was in the workshop manual next to the image you attached earlier.

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[philthehill]

Found it.
For the 1098cc with HS2 carb yes it is 1/8".

[dudload]

http://sucarb.co.uk/technical-hs-type-c ... djustments
I know you stated the wksp manual but what manual did you find the 1/8" float clearance in as in the link above it states 5/16". See also reference to fuel height in the jet. The carb fitted to the 1098cc engine should be a HS2.
Looking at the above link there is nothing that springs right out at me but it could be the top of the jet sleeve.
The block casting number is sure way of determining the block cubic capacity. The block casting number can be found cast into the block just below the rear tappet chest cover. The casting number should be 12A497.

Strange, hoping it's not a major part in that case. Can't see anywhere it would go on the actual jet as it's the same diameter! Hoping it's a part that has been added incorrectly in the past to try and get it leaner, it also has a weak (assume means lean) AB needle installed so hopefully that is the case

[kennatt]

see here http://sucarb.co.uk/technical-hs-type-c ... ismantling item 13 looks like the top of the jet bearing but can't see how it would detach would have though it was one complete unit

[philthehill]

http://sucarb.co.uk/carbspec/carburetto ... s/id/1907/

The standard carb fitted to the 1098cc Minor is the HS2 type AUD13.
The standard needle is AN, the weak needle is EB & the rich needle is H6.

You should aim for replacing the AB needle with a AN. 25% off at the moment.

Looking at the SU needle charts for both AB & AN needles for 0.090 main jets - the AB needle is slightly thinner at all points along its length than the AN needle so will allow more petrol through the jet so it will run richer.
I can recommend the Cars & Car Conversions booklet on Tuning SU Carburettors which includes full needle charts. Copies can sometimes be purchased up on 'e' bay.
or
https://www.ebay.co.uk/itm/SU-Carburett ... SwTkFci~LU

[dudload]

Sorry, my fat finger on phone. Needle is eb!

[philthehill]

So it has got the EB weak needle fitted and is still running rich. A quandary indeed.

[dudload]

see here http://sucarb.co.uk/technical-hs-type-c ... ismantling item 13 looks like the top of the jet bearing but can't see how it would detach would have though it was one complete unit

It's a strange one indeed. Here's how the jet looks like with it installed without that random bit. All looks ok to me!

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