Mini woes

Ta Slater - what happened to the old metro engine? Perhaps it just needs an upgrade. 998cc is sooo sluggish!

Dollywobbler,

What engine and carb does your Mini have? As lordyoung suggests if it is a HS4 carb (float bowl on side), whip the top off the float chamber and check for 'matter' making a nuisance of it's self.

If it's a HiF (float bowl underneath) you will need whip the carb off to have a look in and clean it out. Another problem could be induction leaks, try squirting a can of WD40 at the carb and manifold flanges and also both of the throttle spindle seals when the engine's ticking over, noting if the engine revs pick up when you do so. In worn SUs they can leak air in around the carb spindles due to spindle bore wear. Also, make sure the needle jet isn't badly worn, this is indicated by a pronounced ridge around the top of the needle (not the brass carb needle).

There is also a small internal filter in HiF units, I think anway, so well worth checking to make sure it isn't all gummed up with curse word. Also, make sure the float height is bang on the factory tolerances, too low or too high can make a dramatic difference to how the car will perform.

Another thing, remove the dashpot and make sure the piston and inside of the suction chamber are not covered in 'varnish', if they are, use a fine metal polish to remove it all and then thoroughly wash the polished components, oil with WD40 and reassemble, making sure the piston rises and falls easily, on refilling the dashpot damper with oil and refitting the damper cap, make sure again the action of the piston is smooth and that it doesn't stick.

I'd definitely fit an inline filter, they're range from around £4 to £10 from most parts factors and only take a minute or two to fit.

Another thing to check is the vacuum advance line, make sure it's not broken, both the rubber connectors at each end are intact and not split or perished. Also make sure the vacuum advance unit is working. To do this, remove the vacuum line from the carb end and suck on the pipe, you should only be be able to suck so much out and on suddenly releasing the vacuum you should hear the advance unit clunk back.

If you can suck unlimited air through the pipe and you can't hear the unit moving, it's most likely a split diaphragm, you don't need to replace the whole dizzy though, just the vacuum unit on the side.


Once you're happy with the fuel system, I'd re-check the timing, plug gaps etc.

There are a few other things you could check, but my creaking old brain won't let me remember! I'll post back when it starts working again

have you got the right oil in your dashpot ?
straight engine oil is too thick, i found 50/50
mix with 3 in 1 was a good mix for it.

Whoa! Thanks folks. Was going to whip the air filter off and have a nose around but was soooo bloomin' cold!! Hopefully tomorrow (longer evening too - woo-hoooo!). It appears to be a HS4 carb as I did spot the float bowl thingy - if that's the thing on the drivers side of the carb.

Dashpot is fine. Thought I'd replaced the dizzy cap. Gonna dash out now and check if there are any pretty underbonnet happenings...