Acceleration

[Kenny]

Hi Folks,, well, got a lot done over the last few days to JJ9069, had help few weeks ago from a friend who helped me set up the timing etc. Today, engine temp normal, revving very well whilst stationary, HOWEVER, when under load / moving away even with the pedal down, the engine is very hesitant????????

[Ronald]

Kenny, this could be several issues, first one i would check is throttle movement, ie, whilst you may be pushing the throttle pedal quite firmly, are you actually geting full movement on the carb spindle...... i looked at one car last yr, and he only had about 2/3rds spindle travel, and no-one could work out why it was so slow.......

the other thing is timing, do you have manual advance...>? is it advancing?? if not, then it will be very pedestrian like.....

The last thing that springs to mind is mixture, what colour are the plugs.... whilst an engine can rev quite freely not under load, sometimes a weak mixture can only show up under load.........

Good luck, and keep us posted!

[Kenny]

Hi Ronald,, many thanks for the input!! Throttle movement is okay, the timing I set up with a friend a few weeks ago, and the manual advance/retard working well,, my friend and I (like yourself) are now looking at the mixture, whilst stationary the engine revs no problem, I checked the spark plugs the other day and no.1,2,3 had very good spark but no.4 appeared and sounded a lot weaker, when I changed no.1 and 4 around the weaker spark moved with the plug. I have ordered a new set of plugs from Ian Harris and the arrived yesterday, just in from work today so I will endeavour to replace the plugs tomorrow and fingers crossed all goes well!!!!!!!!!!

I also noticed the carb piston wasn't fully dropping so have cleaned out and put back on, also realised that the piston housing was too tight and when slackened slightly the piston was dropping with the audible noise it should......

[Trevor Wilkinson]

Sounds like the carb jet needs to be centred!

[Kenny]

Thanks Trevor,,, is there an easy way to do or check this????

[Trevor Wilkinson]

Hope this makes sense, it is quite easy.
Start by lifting the piston,with it held up wind the mixture adjuster up as far as it goes ( might be an idea to count the flats so you can return the adjuster to the same spot)
Then loosen the large nut next to the carb body (it is just a matter of releasing it from being tight) and let the piston drop,lift and drop two or three times to make sure it is free.
Re tighten the top nut,recheck that it still drops ok
Re set the mixture adjuster to it's original position
No need to remove carb, just included picture 'cos it was handy!