S3 bogging on full throttle

Hello,

Ive been having an issue with my Series 3, 2.25 petrol:

Upon start up I don't often need the choke, and have to shut it off pretty quickly to prevent poor running if i do use it,

Once warm I have to limit throttle input, if I floor it the engine just bogs,

I should also note, that it often 'diesels' when I shut it off,

Its got a new weber 34 ich, electronic ignition, new ish coil plugs leads and cap and rotor arm,

ive just checked the plugs and threw a timing light on it photos attached:

Ive put a video of it on youtube too:




:



Any suggestions?

It's running very rich and the timing is well off wants to be just after the 6deg mark. Then set the carb, but if it's very old or a cheap copy then you might have no luck

Those plugs are black a sign of very rich running [ a light brown is good] As @kermit_rr says timing first.

That does seem to be very advanced timing. Mine is running about 10 btdc at idle speed with the vacuum advance disconnected and running on E5 99 octane petrol. You could also be running rich but if your timing is too far out you will also be getting incomplete combustion which will also cause sooty plugs.

kermit_rr said:

It's running very rich and the timing is well off wants to be just after the 6deg mark. Then set the carb, but if it's very old or a cheap copy then you might have no luck

Click to expand...

Thanks Kermit,

its a brand new weber so should be able to!

thanks, Ill try adjusting the timing and tinker with the mixture screw,

Tim_AM said:

Thanks Kermit,

its a brand new weber so should be able to!

thanks, Ill try adjusting the timing and tinker with the mixture screw,

Click to expand...

Get the timing right first then check the mixture after, but you might need to adjust the revs a bit as you go

kermit_rr said:

Get the timing right first then check the mixture after, but you might need to adjust the revs a bit as you go

Click to expand...

Thanks K, when you say adjust the revs you mean the throttle linkage?

Tim_AM said:

Thanks K, when you say adjust the revs you mean the throttle linkage?

Click to expand...

I mean the sprung adjuster screw on the throttle butterfly

I found the Gunson Colortune very useful for setting the fuel mix on my 2a.
A device that allows one to view what is happening inside the combustion chamber.