Strange running problem

[bmcecosse]

I think the Bosch may now be made in the same place as Lucas....... I would go with Distributor Docter who seems to get good reviews on here. Just check it is 3.2 ohms when it arrives.

[James k]

It seems that the problem isn't yet solved! I was driving yesterday and after a long drive, suddenly the car started idling rough, almost cutting out. Again, it seemed like the choke was stuck out but it wasn't. This time it was accompanied by a smell of fuel. After driving the short distance back home, it was idling fine again. Any ideas?

[bmcecosse]

Flooding carb...look to the float valve.

[myoldjalopy]

Yes, float valve may be worn or occasional dirt sticking it open - is fuel pump filter working OK?
Failing that, maybe carb suction chamber and piston need a clean? It is an intermittent problem, which makes it a trickey one to fix, but it does sound like a fuel issue.
But what did happen in the end about that arcing coil?

[James k]

I suspected that it might be thinking about when you suggested it before. Is it possible for it to only occasionally flood then? The carb does need an overhaul I think. The engine speed is dramatically affected by placing a finger over the throttle spindle holes so I reckon they need rebushing.

The arcing coil is still arcing as far as I know and could be contributing to a rough idle :/ It is idling worse than it should in general and gets worse when it's hot. There's a popping sound from the engine.

[bmcecosse]

Chase up another carb - 1.5" SU if you can get it on a decent inlet manifold. It's hardly worth 'reconditioning' a tiny 1.25" SU. Here you go .... http://www.ebay.co.uk/itm/classic-mini- ... SwmtJXW~Zn

[pandaman]

Evening All
Try painting over the tracking area with clear nail varnish, it works on mother boards.
Regards Pandaman.

[myoldjalopy]

[quote="James k"] Is it possible for it to only occasionally flood then?

Yes, sometimes dirt can jam the float needle valve open for a bit, it floods, and then the dirt is washed away and the valve operates normally again. That's why I asked about your pump filter - if its old/damaged, it could be letting dirt through...which could also cause an occassional sticking piston.

But I wouldn't leave an arcing coil in the car. If the ignition system isn't known to be A1 then that could compromise your investigations into the fuel side.

[bmcecosse]

Note that slight air leakage at the carb spindle only upsets the idle slightly (maybe 1% of engine running ??) - it matters not when running along, so don't get too hung up on that.

[James k]

Is there any advantage to the HS4 without further modifications. Also, I will enjoy rebuilding mine I should probably do the fuel pump at the same time or at least clean out the filter. As for the arcing at the coil, I may just buy a new Bosch one when I've got some money spare!

[bmcecosse]

Yes - the larger carb on a decent alloy inlet manifold will release a few more BHP. Change that coil asap - an 'arcing coil' is only going to get worse and let you down... Although I say it's never the coil - there are limits - and if the HT is shorting across the top, it's a breakdown waiting to happen. Just be sure to get a 3.2 ohms coil - and not a 'ballast' 2.2ohm coil.... Make that the top priority -then worry about the carb. A 'secret switch' of course will allow you to test if the carb is overflowing - just switch the pump off for a few seconds and see if the problem disappears!