3 replies to this topic

[Russet Brown]

What’s the consensus, I am looking at refurbing my HS4 carb which has a waxstat jet for my 1980 1275GT Some say for reliability it’s worth while changing out to a fixed jet?

[Spider]

I found they drift too much, perhaps it's our local climate and temps ? They don't age too well either. I always change them out for the fixed type.

[68+86auto]

Much cheaper to get rid of it.

[Shooter63]

The problem you will have is that other parts will need to be replaced as well, you will need a new needle as these wear, the spring is also way past it's best, and a good chance the throttle spindle will have wear. Ive just changed a waxstat to a normal jet, you need the special modified jet and linkage, it took me a bit of time to suss out the return spring arrangement. I was lucky in that the carb body bushings were OK, if they aren't you need to change them, without a lathe or mill, I'm not sure how it's possible but there are companies about ( mainly MGB specialists)that will do it for you.

I used a genuine SU rebuild kit and found a couple of problems.

The new throttle spindle wasn't straight and was binding badly, I was half shafting the spindle and as soon as I cut it, the bind went away, which made me think some sort of stress was put into the shaft during the slitting process.

The new butterfly was so misshaped, there was no way I could get it to seal, so used the old one which worked perfectly.

You may be better off getting a re-built one from a reliable source.

 

Shooter