Folks,
I'd like to get the carbs checked/retuned on my SP250. At the recent MoT I was advised it might be running a little rich.
Philip Glennerster did a superb job rebuilding my SP250 engine in May 2013. Had he been in business I'd have gone to him but I don't know of a trusted person now to turn to.
Could a club member recommend someone for me.
I'm Northamptonshire.
BHX707A

Phil Glennerster restored my car's engine in the winter 2013/14 so it must have been just after your's.

I also thought my car was running a bit rich so I turned the lower two mixture screws only 1/8 turn anti-clockwise and the car has run brilliantly ever since. It revs evenly right through the range, pulls away quickly in top and the exhaust pipes are reasonably clean.

There is a way of testing the mixture by raising the external needle piston 1/32 of an inch (0.031") to see if the engine revs reduce (too weak) or increase (too rich), but I've always failed to discern anything useful doing this. It's too small an adjustment to make!

The large upper screws are to adjust the idle speed; listen to each and ensure that the hiss is the same from each.

Lots of cars have twin SU carbs so there should be lots of capable people to adjust them, and I would also be pleased to have some recommendations.

Hi, in my recent thread on Rolling Road I mentioned the car was tuned. This was done by Colin at Southam Mini and Metro Centre 01926 815681 so not too far from you. They are a traditional workshop and have good reviews. He checked the jets, needles and operation. Balanced the carbs and checked/adjusted the mixture and checked timing, before running the car on the Rolling Road. I was happy with the service and the car seemed more responsive with smoother acceleration on the way home.

If you live in East Northants you're not too far from me. I regularly check the tuning on my V8 250 saloon carbs & make the necessary adjustments - if you can get your car to my place I'll happily have a look, make any needed adjustments & offer you guidance on the various adjustments you can make. I stress that I am just an enthusiast, not a professional, but have had several classic cars with twin SU carbs and have successfully kept them in tune.

David,

You can tune your carbs yourself. I have a simple check list that I use and get good results and I'm no expert! I tried to attach it without success (tuning carbs is easier). Send me a PM and I'll send it to you.

Cheers
Michael

The workshop manual has an excellent guide to set up. If you don't want to DIY then the guide would guide any budding amateur mechanic or modern garage that doesn't know what a carburettor is.

To everyone who responded to my request for advice,

Many thanks for your constructive replies. Sorry not to have replied sooner. I did take RadfordJim's advice and took the car to Colin at Southam Mini and Metro Centre and Colin confirmed it was running very rich.

On the rolling road Colin set up the carbs and, after an initial bit of weak running, got the carbs spot on. The car is now very responsive and has a much criser exhaust note.

There's more … Colin discovered that the carb linkage was catching on itself limiting the extent of travel; I was only using 60% of available throttle (probably a good thing for a new engine!). He also corrected a choke cable problem for me.

I would not hesitate to recommend Colin and the team at Southam Mini and Metro Centre; very professional indeed.

DWS

I'm really pleased you got the carbs sorted David. Colin is a whizz tuning SUs and you know it's done correctly on the rolling road.

Colin's Father, Rod analysed and fixed my steering castor problem (as mentioned in another thread) and I watched Colin tune two racing minis whilst I was waiting. Very impressive!

My carbs have just been thoroughly rebuilt by a company in Redditch. There was wear in the shafts and all sorts of things I did not know about. Engine seems to be running extremely smoothly now and I guess there are no longer any air leaks.

I can get you details if you would like them but it wasn't cheap.

SimonP