Morris Minor Owners Club

I have just spent a jolly afternoon fitting a 1 3/4" SS exhaust, Howley inlet manifold and HS4 carb to Mr Ugabugchugabug's '57 saloon, Muriel.
Not having had any previous experience with an HS4 carb, can anyone offer me some advice / tips on setting it up?

Thanks

Andy

should be similar to the hs2, just a bit bigger. to get it running smoothly you really need to choose a suitable needle - http://www.winsu.co.uk is the way to go, but just to get it running you should be able to use whatever needles is in there. have you tried starting it yet? what happens?

Picky

Thanks Picky!
I have had it running....and taken it for a short spin, but there is no power when it is put under load ie. up a hill

could be the timing is now wrong for the engine spec, as well as carburetor issues. the needle really needs sorting out, also check the mixture, the carb should have a lift pin like the hs2 carbs. what capacity is this engine?? any other mods except the ones you mention?

Picky

Before I carried out these mods the car was running like a dream with standard carb / manifold / exhaust
Engine is basically 1098
Andy

get the right needle using the winsu software (basically you tell it what your engine spec is and it suggests a needle profile, which you then go out and purchase)

and check timing and mixture as said before. you have connected the vacumm advance to the new carb?

Are you running with an air filter?

Is there oil in the dashpot?

Sounds to me like the piston is rising too quickly and or too far. This can be from no oil in the damper (the black knob on top), or simply too little air resistance for the needle/ spring (no air filter). First check is the damper as A series engines tend to pull fine with no filter (until they wear out that is!), then maybe consider a stiffer spring (IIRC the Minor HS2 uses a yellow spring, the HS4 might have a red - When new they have a dab of colourted paint to tell, but the yellow is basically stiffer and with less coils). The one in your old carb might be the stronger type, if so fit it and see if things improve. The spring is accessed by removing the carb top, 2 screws on the HS2, 3 on the HS4.

Sophie (948, HS4 carb, 1098 cam and 12G940 head) ran a bit flat, so I invested in some rolling road time. Much better now and we found a problem with the jet assembly so have ordered a new one and will go back this week, I hope, to finish the job. I'll post later how it goes.

What's the problem with the Jet assembly ??
Back to original poster - probably hopelessly wrong needle in the carb - take it out and note the code on the shank - and also try fitting the needle from the original carb (and note the code on it too!). First step is to set the fuel level - if it's way too low the carb won't be able to suck in enough fuel.

For reference, the Haynes BoL claims the 1098 Mini (HS4, same head, prob same cam as a Minor) had a red spring and an ABP needle, if that helps? The better exhaust will alter the optimum needle, but I'd expect the standard (ABP) one to be at least driveable!

Hi All

Many thanks for all your tips, the car for the time being has a standard SS exhaust and the old HS2 back on and she is running like a dream again, will ponder how to make the big bore fit nicely and also play about with the HS4 or the (Brand New!) Hif44 we have.

Andy

Hello all,

just a point relevant to this post, using the lift pin to check the mixture is only applicable with the right needle.
As all needles of the same size .g.e 0.090, have much the same idle setting, so getting the mixture right at idle will happen irrespective of the needle fitted. That is not to say that the car will run well.

In other words getting the idle mixture right doesn't automatically mean the rest of the range is correct, and it probably will not be.

Alec

Sophies set up has ended up with AAU which is right up to 4000 rpm - thats as far as we went.

Roger

I have to say - if the car is running well - why are you worrying about changing the carb? Leave it alone! Bigger carb only helps give more power at high revs/full throttle - when the original carb would have run out of air flow capability -so unless you already drive often at full throttle and high revs -there will be no benefit.