74 TR6 US spec running rich

[Sterly]

I'm currently working on an imported (to the UK) TR6 of unknown history.  The car was not running when it arrived so I'm working my way through repairing/restoring.  I'm currently trying to get it running well but despite fitting rebuild kits to both Strombergs it's running rich, noticeable black smoke when warmed up.  Floats I believe are set correctly, temperature compensators adjusted per the Buckeye write-up, no oil leaks now from the chamber air valves, the adjustable jets turned counterclockwise just over 2 turns, carbs balanced.  Both air valves move up and down nicely.  I have disconnected the hoses for the smog stuff and blocked the ports off.  All plugs are sooted.  One other thing is that while the engine revs very cleanly, it's not that smooth at constant revs.  The engine's a bit worn and the compressions are all around 125.  Timing adjustments make no difference to the richness.  Ignition dwell spot on, new points.  It starts from cold with little or no choke and I can push the choke in very soon after.  I was wondering if I should try lowering the floats?  Manifold vacuum is on the low side of normal and flickers - maybe a valve/guide problem?  

The jets/needles have not been replaced - are these carbs with the adjustable needles prone to jet/needle wear? The jets look OK to the naked eye. 

Can anyone suggest what might be the cause of the richness?

Thanks in advance

Mark

[stuart]

If they’re later Strombergs they may have the temperature compensators on the side that are a known problem 

Stuart

[harlequin]

1 hour ago, stuart said:

If they’re later Strombergs they may have the temperature compensators on the side that are a known problem 

Stuart

Agreed the temperature compensators can be a problem and are not required in the UK. Plug the ports and that will take them out of the equation. In addition its worth disabling the bypass valves, this can easily be done by fitting a solid gasket. 

These modifications are described on Edd Hollingsworth's excellent website https://bullfire.net/TR6/TR6-20/TR6-20.html

 

Also you mentioned you have removed the plumbing from carbs to smog stuff and plugged the ports, it may be best to run a pipe between the ports on the carbs with a tee to the rocker box vent spigot.

George 

[poolboy]

If there are Grose Jets instaed of needle valves in the float chamber..remove the Grose jets and replace them with needle valves and reset the float height.