Does the manual shooter rod work normally?

Any chance you have a cliffy on the shooter lane. I’ve had the same problem when one gets out of alignment and the ball Hangs up on it.

Check to see if both fingers of the auto plunge are hitting the ball squarely so it sends the ball out straight. Next check the lane guide of the ball launch to make sure it’s not effecting the trajectory and adjust if needed.

I'm having the same problem on my Bksor. It worked fine until this lockdown we've had. I've taken everything apart cleaned it and replaced the coil sleeve, now sometimes it works sometimes it doesn't. The power is maxed out.

It really becomes a pain in the butt when you get six multi balls going.

Check if shooter rod tip is centered in-between forks of plunger and not close to either side. You said you changed coil but did sleeve get replaced? Sometimes just cleaning inside the sleeve with 90% alcohol with a piece of scotch-brite pad and also the plunger rod will make a big difference.

Check to see if there’s a crack in this anywhere.
6B2E679A-51F5-4DA4-9518-B42DA3A10F10 (resized).jpeg. I’ve had a couple of these go from cracked to totally broken within a few games.

Forks should be touching the ball and not as spread out, surprised your not having issues still but if it's working now then I would just leave it.

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If you have any velcro with the sticky backing, you can cut a small piece and put it between bottom of playfield and where linkage contacts it making the forks not rest so far back like yours are. See the picture in post #11, area I'm talking about is to the far left of the circle in the picture.

I had a similar problem on my Family Guy, that auto plunge would work erratic, the washer around the shooter rod next to the spring was beat up, it would bind on the rod and hold it in too far after the manual plunge and keep the ball too far ahead.

Here's a picture of the area I'm talking about and the thread it came from.

https://pinside.com/pinball/forum/topic/tech-help-please-acdc-autofire-plunger-getting-weaker-and-weaker

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I still can't get mine to work consistent.

I had something similar happen. first time I looked everything checked out, worked perfectly. Then someone said it was messing again up a week later, I checked it and found a screw that was somewhat loose causing it to bind every so often.

There was an older post about this problem, What is holding your shooter spring on?
The problem on the old post was that the e-clip stuck out just enough that it impeded the auto plunger.

There are two bushings on the pivot point. I had issues with mine, inspection showed the bushings were: 1. worn. 2. the other shot. Replaced them both and bought extra spares. 545-5352-00 NYLINER, 3/16" SHAFT, 545-5423-00 NYLINER, 1/4" SHAFT, 4L1-FF

Adding velcro, bending the bracket so it touches the ball evenly on both sides seems to be working so far. Thank you.

Reviving an old thread instead of making a new one to keep the conversation going about something that needs to be dealt with at Stern.

I'm on my 2nd NIB Stern in a row where the auto plunger is just weak. Straight out of the box, my Avengers Premium barely made it all the way around the orbit/ramp, failing maybe 20% of the time. And now that I've got maybe 50 games on it, it's down to below 5% success rate. It's just too damn weak.

Previously I had a Jurassic Park that, in the same way, was about a 80% success out of the box, then dropped to near 0% success VERY quickly. These are home use games, not played very hard at all. And once those auto plungers start to miss, it doesn't matter if the game is booting up for the first time, or the coil has been fired 25 times in a half hour, it just sucks.

I've tried it all - bending the forks, doing the velcro trick, coil sleeve replacement (this shouldn't have to be a thing at such low plays, but whatever, tried it).

Has anyone made any progress on improving this issue? I'd be willing to buy the parts and rebuild it however necessary.

I am having the same issue on my Deadpool. I bent the forks and tried the Velcro. Added a washer or two at the rod/fork assembly thinking that taking out the slop would help. Turned up the power. Replaced the coil sleeve. Nothing helps.

Every time I fire it up the auto launch works good the first 5 times and then gets weaker and can’t make the orbit. I ordered the nylon bushings and will swap those in to see if that helps.

Here is mine. I bent the left fork in a bit as the ball was mostly propped up by the left fork and not resting on the right fork.

No big difference as it works fine for a few plunges but seems to get weaker.

Anyone know how to test voltage on the coil and what reading I should get on my multimeter? Also what do I set my MM to?

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I have fought with many auto plungers. I honestly think it's just the nature of the design. There is a ton of slop in the mechanism, in multiple places. Some game designs do not suffer because of it, but some definitely do. Some games can be tweaked enough to overcome the slop, but some just can't. I think until that mech is redesigned with much tighter tolerances or fewer assembly joints, there is always going to be some percentage of plunges that just go wonky. A combination of shooter lane design and tolerance stack-up in the mechanism parts is going to determine which machines suffer and which do not. There are things you can do to minimize that percentage (and it sounds like you've done most of them), but some games are just never going to be 100%.

Anyone else come up with other solutions or just what’s posted ? BKSOR acting up now.

i had a problem with mine until i adjusted the Cliffy in the shooter lane. didn't have it aligned right and so the auto plunger would get progressively worse as games went on, maybe try that if you have a shooter lane protector installed

Can you post a pic, right or left side for the Cliffy, I have both. Haven’t tried anything yet.

it was the right side one that was my problem, i didnt have it overlapping the wood enough and had to push it out a little more towards where the ball comes out. make sure those screws holding the side rails in are really locked down tight

I had a cliffy's in mine but the left side piece never quite fit properly and was causing shooter issues. In particular because the positioning of the 2 holes on the left piece misaligned it was causing it to bow up at the top and bottom. I dunno if Cliff has changed his pattern for this but I did reach out to him about a year ago and he indicated that Stern has moved the positioning slightly since he first started making those which is causing issues.

End of the day I just removed them from my Deadpool until I can figure something out and the auto plunge is so smooth now. I would prefer to have it protected but even at full strength it was becoming maddening to not have the auto plunge work properly.

Jrotten for myself it was definitely the left side that was giving me grief.

Got it, I will try tomorrow, my left side went in ok but the lower fin shank screw broke on reinstall, I put a pan head screw to replace it since Marco is out of them. That was 3-4 months ago & this issue just started yesterday so maybe I’ll remove them & bend the forks slightly. Coil & sleeve are all clean, spring is good. IDK, but thanks for the reply. J

I’ll check it tomorrow, from what I remember on the right I had initially pushed in as far as I could. I couldn’t go to far as the mounting holes in the Cliffy were only so big. Maybe I’ll just take them out. Thanks guys, J

Hah I did the same thing. Broke the screw trying to tighten it down and I too can't get a replacement right now so I just took it out entirely for now.

My left side is perfectly flush & holes were perfect so I didn’t have the bowing issue. WTF on those cheap shit Stern shank screws. I didn’t even get it all the way tight & it snapped. Of course no one has them.

So I tried bending the forks, added Velcro, works ok but not consistently, there is way to much left to right play/slop. Maybe the plastic bushings are worn so I’m gonna do that also. Anyway, I have a auto plunger on the Scared Stiff pin that is just built differently. Much better setup that I wish I could adapt to the Stern set up. Part # A-21022 for the Bally/Williams assembly. Looking at it, that mech is built much better. It’s the same principal as the Stern but don’t know if they could be adapted with serious modifications, maybe if whole mech is switched out. Just some thoughts, since I never had a issue with the Bally setup. J

Left is Stern, Right is Bally assembly.

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A few weeks ago I obtained a DeadPool Prem. pb game with the auto/shooter problem and I have figured out a simple fix (at least it worked for me) for this problem of the auto shooter not having enough power shooting the ball to reach the pf, and here it is for anyone with a DeadPool (or other Stern games with the same shooter mechanism) having the same problem: I shimmed up (or should I say down) the auto shooter ass'y (at the lower end only, which is close to the lower edge of the pf) by placing 2-washers (approx. .050" thick each) between the mounting plate for the auto shooter ass'y and the underside of the pf, close to the lower edge of the pf plywood. One washer on the left side of the plate and the other on the right side. I didn't place the washers on the threaded studs that hold the ass'y in place, but rather as close to the lower end of the mounting plate that was easy to insert the washers in between the pf and the mounting plate. You only have to loosen (and not remove) the 4-nuts which hold the ass'y to the pf underside and shove the washers in. I glued the washers to the mounting plate so they would stay in place in case anyone (in the future) ever removes the auto shooter ass'y. I hope this information is helpful to someone who is experiencing this same problem. Apparently the previous owner of my DP was living with this problem for a long time - he bought the game NIB in 2018. Another thing worth mentioning here is that when retightening the 4-nuts that secure the ass'y plate to the pf underside, don't tighten the nuts very tight - I sheared off one of the threaded studs that the nuts get screwed onto by tightening the nut too much. I remember that when I first removed these nuts they all seemed only slightly tight - I think that Stern knew these threaded studs were prone to break and told the assembly line personnel not to tighten the nuts very hard. Luckily the stud broke deep enough in the hole that I was able to screw in a short sheet metal screw to tightly hold the ass'y plate at that location. See the pic to see the washers in place for shimming the ass'y (black arrows), and also to see the screw that I used to replace the broken threaded stud & nut (red arrow).

I bought a Stern Godzilla Prem. game (NIB) in April 2022, with the auto/shooter mechanism working perfectly, so I closely inspected and compared the mechanisms of the DP and GZ pb games and saw a very slight difference (about 1/32") in where the mechanisms were installed, and concluded (guessed) that shimming (as explained above) might solve the problem, which it did on my very first attempt.

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I will try this on BKSOR, it may help. I broke one of those fin shank screws when doing Cliffys & no one has them. So I installed a 6/32” screw from the top & nut/washer on the bottom. Those screws from Stern are total shit. Of course no one has the fin shanks in stock. J

Wonder if this would work on my Elvis, gonna ty... as I have same issue

* Possible Solution *

I've had an issue with an auto-plunger that is really weak on my Jurassic Park no matter how much I turned up the coil power. Been trying all sorts of stuff for a month or two, but nothing has worked until today. I took apart the mech and realized that the spring is larger on one end than the other, and I had the larger end down near the coil sleeve. When the auto-plunger actuated, part of the spring would rub up against the coil sleeve and cause some friction slowing down the throw. All I did was switch the spring around so the smaller end of the spring was at the coil sleeve end (it now sits on top of the coil sleeve instead of around it). It's working like new now Hopefully this works for others as well

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Update on my previous post: Since I fixed the problem with the weak plunges from the auto-shooter on my Deadpool, I installed a shooter lane protector (from pindefender) and the weak auto plunges started again. This shooter lane protector is 3D printed and maybe 1 mm thick, which actually raises the ball this same 1 mm in relation the the auto-plunger. I removed the shims I originally installed to fix the auto-plunger problem (prior to installing the shooter lane protector - explained in my previous post) in the mounting of the mechanism and the auto-shooter again works perfectly every time. My conclusion is that the proper performance of Stern's auto-plunger, which is used in many of it's games, is very sensitive to how accurately it is installed in the factory, and that the tolerance of the exact location that the mechanism is actually installed is greater than the tolerance necessary for proper operation of this mechanism. I know that this mechanism is not installed precisely uniform in every pb game which leaves the factory because I have 2-games, GZ & DP, and I very precisely measured and discovered that there are very slight differences in where the mechanism is located (installed) in relation to the actual plunger.

I agree. This mech is VERY sensitive and consequently it works unreliably because even little variations in games will disturb it.
I also think there is alignment variation in the games and the auto-fire mech suffers as a result. I have a game right now with what looks like a perfectly fine auto-fire mech but its kicker arm rubs on the stainless ballguide that flanks the right side of the shooter lane. The problem is actually the rail to which that ballguide is screwed: it leans left, into the shooter lane! As crazy as it sounds, I have a game where the kicker arm is NOT centered over the milled groove in the shooter lane. There is no way to move the kicker arm left/right, so an alignment issue like that forces you to bend the kicker arm into a parallelogram, which, while it sort of works, doesn't work as well as it needs to.

If you have seen Jack Danger's tour of the Stern factory, you will remember he introduces us to this ancient Gottlieb playfield-drilling machine. He admits that they have only one and EVERY playfield at Stern is drilled/routed using this one machine. I have had enough Stern machines to know that the bits used in this machine don't always pierce the playfield in exactly the same spots; there is very minor deviation, and that translates to very minor relocation of parts on the playfield.

Another mystery with Stern auto-fire mechs is how they seem to have adequate power one second and not adequate power the next. If you meter the power at the coil, it's constant, but it doesn't behave that way during game play. Replacing the coil sleeve, cleaning the plunger, and replacing the Nyliners on the kicker arm's axle, should all be done, but they don't really solve the problem. Even when the action of the mech feels completely bind free, it still can't function with the same oomph every time. It's a maddening mystery for sure.

Has this worked long-term for you?

Also wondering the same as I'm having this issues with my 2020 turtles premium. Thinking it could also be ball magnetism but waiting on demagnetizer to vet that out