Carb Fan / Cooling (UPDATE)
Turbo Mini Forums

Gents,

Just looking for a little help advise.

Its been a while since I've had the mini out and it was a nice day on saturday so i fired her up and went for a blast. The only changes since emu last outings is i have managed to fit the bonnet properly. Perviously it was raised at the rear due to the piping around the plenum chamber just stopping the bonnet fitting correct. I have since changed the hoses and done some repositioning.

Anyway...... After 10-15 minutes of blasting around (fairly spirited driving) i had to pull to one side of the road to let a car past traffic, on depressing the clutch the mini cut out. It didn't start straight away and after 5 minutes of having the bonnet off and having a poke around i didn't see anything wrong. I then went back in the car and it started.

I turned around and started to go home, it happened again when i pulled up to a junction. It wouldn't start immediately again.

I tried multiple things to get it started immediately, no choke, then choke, open throttle, no throttle etc. with no luck

I think it is the fuelling. The carb getting hot and fuel changing phase within it.

It sort of makes sense to me due to the change in air flow through the engine bay and my fairly spirited driving.

I do have a stainless steel heat shield fitted.

I have made up some prototypes for a small fan above the carb on a thermostatic switch and have also extended the heat shield to come further round the carb past the throttle and choke but with a hole for the mixture screw.

Here are a few mock ups of the fan plate.

I plan on running some ducting to the fan..

whats your thoughts...

Edited by mossy2a on 8th Mar, 2015.

Before owt else I would return the bonnet to where it was eg raised and see if your problem goes away. The Metro turbos were known for poor hot starting but that was usually when shut down and left for 5 minutes say at a petrol station.

I had the same problem on a n/a 998. One of the plug leads was breaking down with high under bonnet temps. It would splutter and die. 5 minutes later it would run fine for a short while.

maybe i have jumped to conclusions.......

Edited by BENROSS on 26th Feb, 2015.

The A35 used to be a real pain to start when hot, but since Robert set it up it is fine.even when it has stood for 5 minutes.

I do have a cold air feed to the area round the hot side of the engine, but that stops when the car does, of course.

another good head scratcher that can cause this is the little black module on the side of the dizzy.

Crap in the fuel tank ! Check your inline filter etc

Im running MJ. Although like several of you guys have said, it could well be the coil / leads / plugs.

It was weird, when it did start, it would rev freely and pick up like normal, it was only on idle it would go to die.

whats the in car afr gauge say when this happens?

perhaps take a spare plug and ground wire with you and when it whont start check each lead has spark on in??

have you got fuel pressure during the no start deal

on a side note be good if there was a way to have a feed and return in the bowl to allways have fresh fuel in there so long as the pumps running like when you fill up the tank and go to hot start it put the key on ign for 30 seconds then start it and hae fresh cold fuel in the bowl

OMFG

after many many hours of checking, cleaning and eetting up i 'think' i have found my problem.

I have not fixed it yet but i can replicate my problem.

I have checked the coils, had them tested, new plugs, seed around with the carb done everything. It was only in the heat of the moment i took the damper out the top and it started and idled perfectly, revved ok. I put the cap back on and it seemed ok. went for a blast and the twat cut out again. Took the damper out and the needle holder is not fully returning without a faint touch, something is catching somewhere but until further investigation when i touch the top of the needle holder (i don't know its technical name) it would return a further 8 isn mm and then fire straight back up and rev nicely.

I think i got away with it zoo much on my spirited drive as i was normally no where near tick over.

hopefully tonight i can take it app ark and find the reason.

thanks for all the replies. fingers crossed

perhaps the ball bearings in the damper plunger bit are crappy?

I had many hours working on this last night, and found the carb body had some sharp burrs, must have been from factory. I removed and polished with 1500 grit on both slider assembly and carb and it now works a treat, strats, stops, starts again. its like magic..

And here is you making up brackets and wiring in fans

Sometimes the simplest things are the most dificult to see

Edited by Sprocket on 9th Mar, 2015.

If something is worth doing, it's worth doing half of.

Dazed and Confused....

I had something similar happen, the piston would stick a bit in the carb during a bit of a blat and not return back down. It would stall and not start, if I pulled the plunger out it would drop and the problem was fixed. In my case I had some grit in the carb sticking the piston, it turned out to be swarf coming from my modded intercooler.