Spica microswitch adjustment?

[Kevin Trent <trentkc@domain.elided>]

My 73 GTV with Spica has a sluggish fuel cutoff/deceleration circuit.   I 
believe that the decel circuit (microswitch) is not adjusted properly - it 
deenergizes the solenoid at approximately 1800-1900 rpm.

By comparison, I also have a 73 spider with a spica pump Wes Ingram rebuilt 
a few years ago. It runs just fine, and the microswitch deenergizes the 
solenoid at around 1400 rpm.

On both cars I hooked up a test light to monitor the behavior of the fuel 
cutoff solenoid on my daily commute.  It is very clear that the spider is 
far more "sensitive" - the test light frequently goes on when I lift on the 
throttle and I do not have to be driving hard or at high rpm.

By comparison, the GTV's decel circuit is much more sluggish - the test 
light does not go on nearly as often.  It is activated predominately when 
coming off high engine rpm or when the throttle is snapped shut, not gently 
released.  On the spider you can activate the decel (light) on and off with 
the throttle in gentle driving; on the GTV you really have to be at much 
higher rpm, and with (more) rapid throttle closings.  It is not possible to 
turn the light on or off with judicious use of the throttle in the 
GTV.  But the system does work, it just takes more sudden action coming off 
throttle and high rpm deceleration to actuate the decel circuit. Finally, 
the GTV also seems much more sensitive to the engine operating temperature, 
e.g., with a fully warmed up engine the decel circuit is a bit more 
active.  Are these symptoms of a improperly adjusted microswitch or a 
failing microswitch?

Both the GTV and spider have the same PLEX igntion and cam timing. Over the 
last 4 tanks of gas in each car, driving the same commute, the spider got 
26.57 mgg, the GTV got 26.25 mpg.

I've read the AROC Spica technical guide, and have an Ingram manual which 
provide the microswitch adjustment procedure..  I think the problem is with 
the micro switch.  The solenoid tests fine.

Question:  Is the microswitch failing or just in need of adjustment?  If it 
is the adjustment, does the plunger gap need to be closer or wider?  Or 
should I just replace the microswitch?  Have any digesters gone through a 
spica  microswitch adjustment (or replacement) that can shed their 
experience on the topic?

I'll replace the spica oil filter, belt and the oil seal at the "cam 
follower" when I do the microswitch adjustment (or replacement).   Anything 
else while I have the injection pump off the car?

Thanks for your advice,

Kevin Trent, Powell, Tennessee 

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