7 replies to this topic

[nollyd]

hi all,just a quick question,my 87 mini auto is great when cold but at the same point of my 6 mile journey every day it starts misfiring,think its when engine has got to a certain temperature.what could be the cause of this,the breather pipes have been removed from both sides of the engine and little filters have been fitted.running a su carb on a 998 engine.any help would be greatfully received.timing is spot on,colourtuned the carb.any ideas guys.cheers.

[KernowCooper]

I would do a elictrical check of plugs and points, cap/leads and rotor if you have not got electronic ignition worth putting in a new condenser, followed by a check of the ignition leads they age and need checking with a ohms meter (info in the FAQs Electrical section)

[dp0352]

Are you running the prescribed octane for the car or higher, what spark plugs are you using, and when did you last inspect the spark plugs?  Low(er) octane and fouled plugs can easily cause this symptom, and both are an easy fix.

[jime17]

Has it got a wax stat on the carb jet assembly? Could be too lean when hot.

[nollyd]

thanks guys,got electronic ignition,use normal unleaded,would u recommend high octane.plugs and leads are fine.when this happens iv tried pulling the choke out but this makes no difference.

[LTSwaby]

It may be that the engine is getting choked up, has the engine been revved at a costant rpm for a period of time? they dont like start stop traffic either

Edited by LTSwaby, 25 October 2013 - 03:44 PM.

[dp0352]

...would u recommend high octane...

 

Depends what rating your regular is.  My 98 is prescribed minimum 95 RON, which in the US would be Premium grade gas (91 AKI).  When I put anything under in the tank, it drives like crap, idles like crap, and turns off on its own terms.  At any rate, I use 95 RON or above and it solved my similar problem.

[nollyd]

Ok cheers for the info guys.