cold start enrichment solenoid

[axis_powers]

Anyone know the size of the lock nut holding the cold start enrichment solenoid on a spica system? My solenoid is sticking when the car is warm and it needs to be removed and adjusted.

I have tried to get in there to remove and or loosen the locknut to no avail. I figure I will have to shorten an open ended wrench to get on there. Looks like a 19 mm wrench maybe. I have tried to loosen the locknut with a punch and there is no room to hammer the punch. I am hoping I wont have to remove the pump just to do this. Right now I am running without power to the solenoid and the thing starts hard, needs to get fixed soon before I wear out my starter!

thanks

[Roadtrip]

If the CSS is sticking, it's probably not the solenoid but the little plastic hydraulic piston at the bottom.

Loosing the CSS will probably just throw it out of adjustment. In order to remove the solenoid (and not just adjust it) you'll have to remove the very small cotter pin that holds the piston rod. It's really small and is accessed through the rear inspection plate. I'd be pretty impressed if you could get it back in while bent over in the engine compartment and using a hand mirror and needle nose pliers. At any rate, there's really no reason to remove the CSS unless it's burned out and being replaced. The CSS locknut is 24mm. A ground-thin crowsfoot will definately loosen it or you might have luck with some needlenose vice-grips.

Those plastic plunger/pistons at the bottom of the rod have been know to swell slightly and hang up in the bore, which is probably what the problem is. If that's indeed the problem, the perm fix is to remove the pump, take the plunger out and mill it VERY slightly about .002-.003" using a drill to spin it and a fine file. As mentioned above, to remove the plunger/piston, you have to remove the very small cotter pin, then extract the rod+plunger through the bottom of the pump (there's a large what looks like a drain plug at the bottom).

But, before you do that, you might check to see if it's just gunked-up inside there. When was the last time the oil was changed in the logic section? Try removing bottom plug to the plunger/piston bore. Be ready for oil to leak out. Then remove the side inspection plate and spray some WD-40 down on the plunger to clean it out. Disconnect the long rod at the pump rear throttle lever and push the lever to the reference screw stop. It will take a little force to overcome the springs. Reach in and move the plunger rod up and down to see how free it is. You have to hold the throttle lever over on the reference screw in order to move the plunger rod by your finger. If it seems pretty free, you might get away with just a cleaning. If not, then you'll have to remove the pump and fix it on the bench.

Before putting the inspection plate back on however, I'd recommend using a big syringe or turkey baster and hose to suck out the old oil in the bottom of the logic section. When all the inspection plates and bottom plug are back in, remove the baro compensator from the top and pour in about a half pint of clean fresh engine oil. You don't have to worry about overfilling, because there's a drain hole back to the sump to maintain the corrrect level. The logic section is splash lubricated from captured dedicated oil and does not receive oil from the engine.

[axis_powers]

John, thanks for the response and suggestion.

I was looking at the SPICA tuneup guide for a '78 and noticed the plunger apparatus and from the picture assumed that the plunger had swelled. When the pump heats up after the first drive, and maybe sits for 10 minutes.,I go to restart the car it is rich beyond belief with horrendous backfiring on overrun. I broke out a small hammer and gave the solenoid a tap tap and the idle settled into its usual rumpety rump. It is ever so slightly hanging up in there, but sure to get worse when the weather warms up. I have a feeling I may have to open the pump up. Changed the pump oil when I bought the car and it wasnt too bad, and looked through the barometric housing and all the levers were very clean.

In addition I believe the cold start solenoid is improperly set too rich. Applying 12 volts to the solenoid while running at operating temp and 2500 rpm instantly kills the motor. I suppose I'll deal with one thing at a time.

Thanks

[Roadtrip]

Actuating the CSS with the engine at ops temp and running should only drop the rpms about 200 or so, so I think it likely that it is set way too rich. Wes Ingram's SPICA guide says actuating the CSS while engine running should "almost" kill the engine. Another point of interest is that as the engine heats up and the themostatic acutator extends to lean the mixture to normal running, a lever action in the pump decreases the relative enrichment (effectiveness) of the CSS solenoid. So if you're stalling a hot engine with CSS actuation, it's probably really rich when cold. Do you note black smoke out the tailpipe on a cold start?

A good beginning point for adjustment of the CSS is about 1/4" to 1/3" from the logic section body to the bottom of the CSS body. Turning the CSS counterclockwise (out) enriches the mixture, while screwing it clockwise (in) leans. Keep in mind also that tightening the locknut will raise (enrichen) the CSS a slight amount.

I have a non operational pump with what appears to be a good plunger. If you'd like to try that one, vice milling your existing one, you're welcome to it. The only condition is I'd like to have one back so my inop display pump is complete.