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BJ8 SU carb float level

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peteatgr

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I'm working on the carbs in my 3000 BJ8 Ph II and am trying to check the float levels. The procedure of inverting the float bowl cover and checking the lever arm position with a specific diameter rod is something even I can see and do. My problem is that I keep finding conflicting information on the proper diameter rod for the check on what I beleive are standard SU carbs delivered with the car in 1967. I believe they're standard HD8. Several different manuals list the HD8 as requiring a 1/8" OD rod to check the float level. But the S.U. Carburetter Company Service Sheet No.AUC 9622 B, Jan. 1966, for Tuning, Adjusting, and Servicing Type HD carbs, and other documents and manuals, indicate using a bar 7/16" OD. Seems like quite a difference in OD and thus quite a difference in the float level in the bowl.

To top things off, now that I have the bowl covers off, I have checked my float levels as they are now set and they appear to be set at 1/2" when the lever arm rests on the jet in the closed position. They are most defintiely not set at 1/8" that's for sure. Until just very recently the car ran fine set this way, but then suddenly began to miss and backfire and not want to even start.

Questions; How can I identify the model of the carbs in my car? What diameter rod are experienced people using for this check? If it's true that "most carburetter problems are electrical problems", any hints on where to start searching for pretty severe rough running that came on over the course of about three miles, then barely limping home and sputtering to a stop in the garage all in less than 5 minutes?
 
Iwouldn't mess with the carbs yet if its not starting its a electrical prob could be the coil or the dist or points or condencer see if you get spark first ,joe curto isn't too far from you he's a good guy give him a call
 
Based on all the trouble folks are having lately, I vote for troubleshooting condenser and coil in that order.

Jeff at Advanced Distributors sells tested condensers for a reasonable price.

I couldn't find the 7/16" reference. The Complete Official manual shows 5/16" in section DDD
 
The 1/8" setting is for carbs with plastic floats. Your HD8s have brass floats. My manual says HD8 are similar to HD6s and gives no more information (in DDD). Figure D.8 for the HD6 shows setting the float with a 7/16" test bar. That's what I have used.

Marv J
 
steveg said:
Based on all the trouble folks are having lately, I vote for troubleshooting condenser and coil in that order.

Jeff at Advanced Distributors sells tested condensers for a reasonable price.

I couldn't find the 7/16" reference. The Complete Official manual shows 5/16" in section DDD
Click to expand...

I stand corrected - the 5/16" in DDD is for the tri-carb HS4s - the 7/16" evidently is the same for HD6s and HD8s.
 
Thanks everyone. The 1/8" reference shall RIP and 7/16" it is. I wonder how mine got to be 1/2"? They'll be corrected. And thanks for the electrical advice. The further I get into this problem the more convinced I am that my carbs are fine. Condensor and coil will be my next targets.
 
Although the service manual says 7/16ths, I have found that on high RPM a starving issue occurs and hard starting on cold motors. I have had very good success using a 5/16s
round bar. Based on what you describe I would check for a clogged fuel filter or possibly a bad pump.
 
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