Ok I Thought I would let you know a few more details of todays research and testing
First off the carb has a brand new brass float, the dizzy, leads and plugs are all new, the plugs were gapped to .044" as thats the standard gap for the Bluebird series 2 L series motor, which is what the dizzy came from.
But today I removed the plugs and regapped them down to .035" and the motor will rev like normal, well pretty close
I think it may be a bit lean as the plugs are a light pinky brown colour and power feels a bit sketchy and buzzy at full throttle once the revs start to climb over 5000rpm.
What is the correct colour for the spark plug? I heard that white is too lean, black is too rich but somewhere in between is about right.
I have a fuel pump with three tubes coming out of it, an inlet, an outlet and another tube I am not sure of, it has a tiny hole in the end of it and fuel will come out of it if I leave it unplugged, I am guessing it is a fuel return line, the motor came out of a C20 vanette
Thanks for all the help gang your all helpful legends

Quote:

Yeah white is lean or hot.A little black is good.

I recently helped a mate do this conversion (vanette a15 to a12)... we used the a12 feed line from the pump to the carby. It has no return.

If the carby floot had sunk it would be flooding at idle.
Reducing the plug gap helped maybe the coil is starting to breakdown, & is missfireing under hard load, maybe you could beg borrow or steal one just to test it. A series dont have a halmonic balencer they are just a steel pulley, very rare to come loose, you would get some niose or vibration if it did.
Trev

ok update number two
well the missing come back again so I am thinking it must be crook plugs as the coil is brand new and it doesn't get hot, I checked the plugs again and it looks to be running lean still so I removed the top of the carby to change the main jets to 150's and noticed the fuel level in the bowl was about an inch so it isn't flooding from a sunk float.
Then I thought i should check the idle mixture screws and then I got a shock, the screws had vibrated themselves to fully seated position which is why it was idling all over the place!
I will fit a new set of plugs and set lean best idle settings again and see if that has fixed it
This just keeps getting stranger, is there something i can do to stop those idle mixture screws from vibrating out of there settings?

Run some fuel injector cleaner or carb cleaner and also check that all your wiring is right for that dizzy. I had a similar problem when I changed to an elec dizzy modded from an e15et. I wasnt running the right type of coil also. Hope it helps.

the carb was rebuilt and chemically cleaned before I bought it and before I rejetted it I blew all the fuel passages out and all the jets out with carby cleaner.
The bosche catalogue reccomends the HEC 715 coil for use on the bluebird series 2 and ferrol errol explained to me how to wire the dizzy up correctly.
I am starting to think that the plugs have gone off even though they look ok I think that by running a bit lean for a while and by having the plugs gapped to .044" it has caused the plugs to fail.
I can remember converted saying something similar about that

In that case plugs are cheap

I have bought a new set of plugs and gapped them to .044", fitted 150 main jets and fitted an O-Ring to the idle mixture screws to stop them from vibrating loose again. I guess all that is left to do is see how it runs now.....fingers crossed

AAAARRRRGGGGHHHH this is driving me nuts!
It runs spot on at cruising speeds and around town I can't fault it no hunting missing or anything. But if I give it a boot ful it is almost like a rev limiter cutting in at about 5500-6000rpm and sometimes it will rev right out liie nothing is wrong, What is going on? the plugs look like the mixture is perfect, I don't know what else to change, the fuel filter perhaps?