803 mark 2 H1 carburetter

[soilman]

Hi, need some help please

My car is running rich, always black plugs, (not oil). Don't seem to be able to alter mixture effectively on the jet.
The needle and jet were replaced a couple of years ago, The jet is centered, the float level is ok and I have cleaned the air filter.
The only thing I noticed was that the float bowl isn't level, should it be dead level?
any Ideas what else I can 't check

many thanks

[mogbob]

Hi Apologies if I'm teaching you to suck eggs at any stage. Is the outside of the carb and it's controls clean and lubricated ? Assuming the relatively new jet and needle haven't been dropped or damaged in any way , was the jet centering done at the same time as replacement or more recently ? Was pressure applied with a pencil ( or similar ) to the top of the piston rod as per the SU Workshop Manual.
Is the needle installed correctly , i.e. the shoulder on the base of the needle is " flush / level " with the face of the piston rod ?
Is the top of the Jet flush with the bridge ( or as the Manual says "fully up " if this position cannot be obtained " ).
With the piston / suction chamber in place ( don't forget to fill with light oil S.A.E. 20 eventually , just below the top of the hollow piston rod ) ,does the piston fall freely onto the bridge when the Lifting pin is released ? Turn down the adjusting nut 1.5 turns. With everything back in place and lubricated , fire up the engine and tune as necessary. Loosen the lock nut ,turn adjusting nut , up to weaken and down to enrich.
There is a Youtube video on centering :- https://www.youtube.com/watch?v=sxVFCY_1aSA. it may be of interest.

" Float bowl isn't level " We are talking main float chamber here , not the float ? Since this bolts to the main carburetter body , have you got some damaged / perished washers / rubber grommets or bits missing altogether ? It should be level but a degree or so out shouldn't affect it's operation. Stupid question I know but the retaining bolt is done up tight , isn't it ?
Hope that gives you a few bits to be going on with. Don't forget to disconnect the battery whilst you're playing around with fuel. You can never run fast enough if a spark ignites petrol !
Please come back again if you get stuck at any stage.
Bob

[soilman]

Hi many thanks for the reply, yes I have watched that video many times love it , all the things you mention I feel are all in good order, the only thing I don't understand is the pencil pressure bit you mentioned, can you explain?
I am totally new to this, had the car 3 years, and I am still on a massive learning curve and appreciate any help.

I must confess I have never disconnected the battery, but I am always working on the car outside so never thought it was a real issue and often I need the battery because I need the fuel pump operating whilst doing the checks?

A friend mentioned to me while we were looking at the car that the float bowl wasn't sitting horizontal, it looks between 5 - 10 degrees off and I thought this would effect the petrol level in the carb? There are different bowls some angled at 20 degrees some at 30 degrees.

regards bruce

[philthehill]

The top face of the float chamber should be horizontal.
If not horizontal the level of the fuel in the float chamber can be effected
See:-
.http://sucarb.co.uk/technical-h-type-ca ... ing-single

That braided fuel pipe may be pulling the float chamber out of horizontal but I suspect that you have the wrong float chamber fitted.

[soilman]

No the hose can’t pull it the float bowl is fixed to the carb by a bolt? The position of the float bowl can axis on the bolt, but it will always be off the horizontal. I have sent a picture to Burlin fuels see what they reckon, I am tempted to buy a reconditioned carb from Esm?

[philthehill]

https://www.morrisminorspares.com/fuel- ... es-p830703

That is why I suggested you have the wrong float chamber fitted.

[soilman]

Hi thanks for your responses/help, I have taken the float chamber off and it is a AUC8402 20 degree, I need a AUC4961 30 degree which will bring the float chamber level.
I have had the car in 2 different reputable garages and both haven't been able to stop it running rich or noticed this issue, yet a chance look by a friend who commented on the float bowl not being level, I can't believe it, it seems so obvious when you know, but I never would have noticed it!
I have found one on ebay for £12.00 and ordered, so hopefully now I will have a chance of getting the car running properly.

regards Bruce

[mogbob]

Bruce ,
Sorry for delay in responding. I've taken a link from the Technical section of the Burlen Fuel Systems website
showing / explaining the official pencil trick. I've found it useful , compared to using the spare third hand that you can never find.
https://sucarb.co.uk/technical
Click on H type carbs and second page Routine Servicing
Bob