Series 3 Petrol - Lumpy running after warmed up

Engine starts and runs fine, after about 8 miles of driving it starts to misfire and run really badly. If I turn it off and try it the following day it follows the same pattern. I thought that it might be a condenser problem so I replaced that with a genuine part not a cheap copy. - no difference.

Any advice gratefully received!

Some sort of heat transfer into the carb from the manifold, or is the coil on its way out?

hiya bud ,when was it last serviced?

Its happening when its warmed up properly....
I used to have problems with vaporization when hot on my....
Series 3 petrol ..but since I made and fitted the heat deflector below no problems..
A misfire can also be caused by a cracked exhaust valve....

Check coil,if it is getting hot after driving some it may be the problem.

Look at points. Check that contacts are sound and not loose.

wammers said:

Look at points. Check that contacts are sound and not loose.

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Thanks for all the ideas - I'll work through them and let you know how I get on.

That's one clean engine in that photo, even the throttle linkages are pristine...how'd you get it so neat? I use gunk but I can't get it all shiny linke that; is the engine and accessories all new?

Thanks John for the compliment....
My Landy was stripped down to its individual component parts....
Each part meticulously examined for wear.... cleaned ..painted and reassembled....

John S said:

That's one clean engine in that photo, even the throttle linkages are pristine...how'd you get it so neat? I use gunk but I can't get it all shiny linke that; is the engine and accessories all new?

Click to expand...