I'm aware of the main problem with using a dishwasher to clean car parts (divorce, isn't it?).

But I've got a mucky 50-year-old carb on my H-van that I'd like to clean up. Is the dishwasher technique purely cosmetic (ie just the outside comes up nice and clean), or does one dismantle every last little piece, jets, regulator screws etc (though I'm fairly sure not the float) and hope to get the innards nice and clean too?

I do have one advantage here, which is that we don't ever use salt or rinse-aid in the dishwater - the water is very soft indeed.

Any other tips would be appreciated (even "don't do it", of course).