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Re: [Healeys] HD8 Slow Run Valve

To: Bob Johnson <bjsbj8@gmail.com>
Subject: Re: [Healeys] HD8 Slow Run Valve
From: Bob Spidell <bspidell@comcast.net>
Date: Sun, 18 Jul 2010 17:31:18 -0700
Bob,

I have one SU book that says to close the slow run valves and adjust the 
idle with the throttle stops only, and one that says, essentially, that 
'the idle must be set only with the slow run valves.'  Go figure.

I split the difference.  In my experience, the SR valves will only give 
600rpm without opening them what I consider an inordinate number of 
turns.  I like to open the SR valves 2 turns--this gives me some leeway 
if I want to slow or speed up the idle depending on conditions (usually, 
altitude); i.e. you can open each valve a half turn, then close them 
back without breaking out the synchronizer (and removing the air 
cleaners--a major PITA).  I also open the throttles a smidgen with the 
throttle stop screws.  I prefer to have the stops stop the throttle 
plates--not the inside of the throttle body.  I have seen where throttle 
plates have worn a groove inside the carb throat, all but ruining the carbs.

The procedure is:

1) close slow run valves
2) adjust and synchronize the carbs with the throttle stops
3) open the SR valves 2 turns--check synchronization (should be pretty 
close)
4) close the throttle screws until desired idle achieved (I like about 
750rpm)
5) check synchronization
6) repeat steps 1-5 as necessary (then, you can start on the fast idle 
settings)

All this notwithstanding, your car should idle steady--if a bit 
rough--at 600rpm on the slow run valves only.  Since your engine stalls, 
something else is not right.  My guess would be timing, dwell and/or 
mixture.


bs




Bob Johnson wrote:
> Fiddling with my carbs yesterday using my Haynes manual. thru the step
> to 11 "Restart the engine and adjust the slow running valve to give
> the desired idling speed of approximately 1000 rpm." Apparently
> screwing the valve down slows the idle, up increases speed. Without
> any further adjustment than the 3 1/2 turn the engine will idle
> momentarily at 500-600 rpm then quite. Turning the valves down makes
> it die more quickly. Turning them up/out will not raise the idle speed
> above 600-700, but it will idle for maybe 30 seconds before stalling.
> This is worse as the engine gets warmer. Any ideas as to what is going
> on? Why will it not pick up speed?
>
> Bob Johnson
> BJ8
> _______________________________________________
>
>
>   


-- 
*******************************************************************
Bob Spidell           San Jose, CA            bspidell@comcast.net

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