Did you check that the arms move freely?

Might have the game high tapped too.

Orange (and yellow) dot coils are PBR aftermarket replacements for Gottlieb flipper coils. They were not designed for slingshots.

Are the correct rubber rings installed on the slings? A smaller size would resist the kicker arm more. Yes, make sure the mechanism moves freely as per a prior poster.

If you're feeling adventurous and you've checked to make sure all the usual suspects (ie friction or worn linkages or dirty parts/contacts) aren't your problem, and you'd still like more powerful slingshots, you can remove layers of wire from the coils themselves. Remove the coil, unwrap the paper, unsolder one end of the wire from a lug and remove wire (which makes the coil more powerful - to a point) until you're happy with the amount of "sling".

Just be careful not to take off too much wire - you reach a point of diminishing returns eventually. I've had good luck with that on pop bumpers on some early games.

Like someone else noted - the yellow and orange dot coils are for flippers - 3 lugs.

I guess you could manage to fit orange dot coils on a slingshot and only wire up 2 terminals; the frame should fit. However, the sling may be seriously stronger than with the original coils. Does your machine use A-5194 coils for the slings?

The 5194 has a spec resistance of 4.5 ohms, whereas the high power side of an orange dot should be closer to 1.3-1.4 ohms. That would make a HUGE difference in the sling power as the current through the coil would more than triple. Watch out for airborne balls off the slings.

Yeah, Lee - that would be a huge difference in the sling's power, like you said. I like taking layers of wire off the coil because you can do it a little at a time and get the results you want - if you don't mind doing alot of soldering and de-soldering.

I did it on a Slick Chick and Magic City and if I remember correctly, the coils' resistance went from maybe 2.4 ohms down to about 1.7 ohms. I think I took off about 2 layers of wire. But I started slowly, took off 1 layer, checked the resistance, put it back together and played it a few times, wasn't quite happy, did it again....until it played the way I wanted it to.

That was for pop bumpers, but it should work just as well for slings. Just make sure you eliminate friction, geometry problems and slop in linkages first before you go this route.

Make sure you have cleaned the pivot points, polished the plungers and replaced the sleeves before messing with the coils. That made a huge difference on my Williams wood rail.

I would strip the slings down and replace the moving parts and check that the coils are in range before removing wire. It can be a hit and miss process plus if too powerful afterward, you risk flying ball damage.

FYI,
I have a Flip-A-Card with all original parts but everything has been cleaned. As I recall the rubber rings I got from PBR were too floppy and I dropped down a size. My sling coils are obviously original parts and are more than powerful enough for the game. Krynski's use of asymmetrical slingshots is just pure genius and add to the wacky fun of this game. I also set the switch contacts to close with very little movement of the rings, so the pulse from the coil really smacks the ball very very quickly. I do not see any need to try to make the stock coil any more powerful than it is unless it does not have the correct resistance, and at that point i would just invest in new coils from your favorite source. I did switch to yellow dot coils for the flippers just for the fun of sending the ball up to the top of the playfield at rapid speed. I drove a 3500 mile round trip to get mine. Playfield is badly worn (I think the paint that was applied to FAC and Card Trix was too thin) but the game plays good as new. I also have a Card Trix but it is on "permanent" loan to a retirement community.