Only fitted this year so still ironing out bits n pieces but thought ide got the carbs set well until last week on a very hot day
If i gunned it in any gear,at around 4k it spluttered until i backed off the throttle
Thought it may have been a blocked jet as ide messed with pump and fitted filters so blew them out
Went out for a run and it was running great again ( cooler day )
As a precaution i fitted a crank sensor as the one the engine came with was still on
Today was my first chance for a blat and it was spluttering again
Went home to have a nosey but all looks good
Back out again without the bonnet on and it was fine
The bonnets not cut for fresh air to carbs ,theyre feeding from in the engine bay
Anyone had similar issues - would a vent in the bonnet help
Any help appreciated
I had similar symptoms with a blocked fuel filter. Disconnect the pipe at the carbs and check the fuel flow rate with and without the filter. http://www.locostbuilders.co.uk/viewthread.php?tid=191347
Thanks for that
Both filters are less than a month old but got to be worth checking as theyre the cheap plastic ones
Sounds like the fuel is vaporising due to high under bonnet temperatures
I have the same setup but with piper cross sausage filter,had no issues running in hot weather
Thats interesting!
Could it be the bonnet disrupting or restricting the air flow causing a major change in air velocity or is it the warm dense air under the bonnet
causing the engine to run rich.
Could check the plugs under both conditions and see what they look like.
Can you try running without the bonnet on to see if it makes a difference?
Plugs look light brown/grey so not rich
Confusing thing is that its right on the money as long as its not over 22 degrees 
Vapourizing makes sense,might kill the ign next time it happens and see if theres anything come out the floats
Bit of a pita when a nice hot day is perfect for these cars
quote:
I have the same setup but with piper cross sausage filter,had no issues running in hot weather
More lumpy than norm and i assumed that was heat
This is like you hit the limiter
Like was said above you need to try it on a hot day with the bonnet off and see if you have any issues.
I've thought of buying a thermometer with remote sensor like this:
(Link) to keep an eye on under bonnet temps. Might not be
100% at this price but would at least give a base line for fault finding.
Stu
Ive tried it without the bonnet - see original post - it was fine
What confuses me is that it will sit happily in traffic,fan cutting in etc,without issues - even on a sunny day
Surely the under bonnet temps must be high in those circumstances