[Healeys] HS4 carb jet head and spitting

john spaur jmsdarch at sbcglobal.net
Thu Jun 6 23:31:15 MDT 2013


I have questions concerning a BT7 tricarb.

While tuning the car, it was noticed the two rear jet heads were at 
about the same level but the front jet head was considerably higher 
(all were below the bottom of the Venturi). It is my understanding 
the height of the seat is related to float height setting and 
lean/rich jet adjustment.

Should I recheck the float levels to see if something is amiss and 
adjust so the jet bearing seats are more uniform before I tune the carbs?

The carbs sometimes spit petrol, while cold (common issue I believe) 
and upon acceleration when the engine is hot. Is this an issue 
related to valve timing and/or rocker clearance? I think spitting 
back fuel can be caused by a too lean condition.

Could the valves be staying open too long? I have a Denis Welch road 
cam which is similar to a BJ8. Per DW, the rocker clearance is set to 
.015 cold.

Needing clues to fine tune the healey.

TIA
John Spaur
San Jose


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