BJ8 Float Level Adjustment?

[stever]

Good day, all! I have a technical question for you: What is the proper float level adjustment measure for the HD8 carburettor used on the BJ8? I have perused several manuals, including the factory workshop manual, the Haynes workshop manual and the handbook to no avail. These manuals give measurements for several other carbs used on Healeys but not the HD8 with metal floats. It appears the choice is between 5/16ths of an inch and 7/16ths of an inch..........or..???? Any help on this would be greatly appreciated. I set them at 5/16ths of an inch last night and the carbs adjusted out nicely and it seems to be running good and all, but it would be great to know I have them set properly. Incidentally, I used my new 'advance adjustable' timing light last night and it worked really great! At last, I know I have the timing set right for a change. The engine timing was about 3 degrees off.......
Thanks a lot in advance!

 

[rcn491]

The Jaguar shop manuals call for HD8 float level to be set at 7/16"

 

[ThomP]

This is one of those mysteries to me too. I have an SU Type HD Carburetter Tuning, Adjusting and Servicing manual that gives the float level as 7/16, while the Complete, Official A-H manual gives 5/16 for this dimension. I compromised and went with 3/8!

From a practical standpoint, I'm not sure it makes much difference. It requires an extra .06 pounds of vacuum to make up the difference. Additionally: the liquid in the float bowl certainly changes that much (and more) when the car goes around the corner.

 

[piman]

Hello Stever,
rcn491 is correct, it should be 7\16" (11mm), HS carburetters are set at 5\16" (Plastic float).

Alec

 

[slider]

Stever,

Hold the float bowl top upside down and use a 7/16 metal twist drill bit or dowel to measure the distance between the float bowl top and the arm to insure you have the clearance you need.

David Z.

 

[stever]

Thank you, Gentlemen, for your assistance. I suppose I will set it at 7/16ths of an inch tonight. I do appreciate your help! Incidentally, the SU carb tool set I have has the aluminum tubes that can be used to set the adjustment. The round one is 5/16ths and the oval one is 7/16ths of an inch - they are a little easier to use than a drill bit. Thanks again, guys!