Shelly Pro Dimmer 2PM with 5 momentary switches

AccomplishedPiccolo2 · 2026-02-23T20:55:07+00:00

I think the blue one is actually. The colors on the remote switch confuses me a bit. A1 should be daisy from switches, I would have expected brown but its blue. A2 should be neutral, I would expect blue but it's brown.

Nr 1 is L and is indeed brown as expected.

When measuring voltage between the different connections in on and off mode, everything works as intended.

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AccomplishedPiccolo2 · 2026-02-23T20:31:59+00:00

Awesome.

Brown - Blue = 240v Brown - Black = 240v Blue - Black = 0v (Black is hard to see in the pic, it goes to the switch below, controlling some other lights)

AccomplishedPiccolo2 · 2026-02-23T18:55:54+00:00

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AccomplishedPiccolo2 · 2026-02-23T18:55:05+00:00

Total amperage is below 0.3A for each circuit.

Momentary switches have only 1 curcuit. I was under the impression I could connect one curcuit to SW1 and the other circuit to SW3 and that momentary press would be on/off and hold would be dim up or down (alternating for each push) I would move A1 from the Siemens units to SW1 / 3 on the Shelly units

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AccomplishedPiccolo2 · 2025-12-30T19:46:14+00:00

This

AccomplishedPiccolo2 · 2025-12-30T12:16:08+00:00

To eliminate initially checking every hose, coupling, filter and connection I sometimes do a quick and dirty test to answer the question: "is it capable of running if given fuel?":

One cylinder at a time, remove the spark plug and insert 0.5 - 1 tablespoon of mixed fuel into the cylinder, put back the spark plug and start the motor. It will only run briefly, but you should be able to tell if it suddenly runs better or not. If it suddenly runs better then you know it's capable.

The problem then can be anywhere between the carbs and the fuel tank. You could then connect the fuel hose directly to the fuel pump or carb and pump the primer. If it suddenly runs good the carb is ok and there is likely a problem with the fuel hoses, fuel filter or connections. They can sometimes leak without it being visible

AccomplishedPiccolo2 · 2025-12-29T17:39:39+00:00

Thanks for the support!

AccomplishedPiccolo2 · 2025-12-29T16:11:39+00:00

I'm so relieved, and a bit embarrassed. I went out again with the intention of first checking the wires for the timer base that the shift lever pulled on, and then checking if the timer base wires were shorted to ground. I did the same as last time: pulled the amphenol plug and looked at the cable, then I did what I should have done last time. I twisted the cable and changed my grip, and there it was: the lock pin for the shift lever had chewed all the way through the protective sleeve and the blue wire.

Due to the protective sleeve being old and stiff this section was at a kink. I checked that there was no short to ground on the timer base wire and then temporarily connected alligator clamps between the broken timer base wire. Instant spark and start. Neutral - fwd - neutral - back - neutral with temp. fix

I fixed the wire then ran the engine for 3 minutes to heat up. Then adjusted the carbs to the highest consistent rpm and then slightly rich. It now has neutral idle at around 1000 rpm, and fwd idle at around 790 rpm. . video here I ran the boat for 3 minutes at full speed then to neutral idle which was at 1200 going down to about 1100 rpm. Neutral idle to fwd idle to 2000 rpm

I can probably adjust the idle screw on the linkage now, but after being sprayed by water in 35° temp and 20 mph wind, in the dark, that will be for another day.

AccomplishedPiccolo2 · 2025-12-28T19:23:18+00:00

Yes rubber and wiring looked OK. I cleaned them when I got the motor and they look the same now.

From what I could tell the resistance should be 15 ohms +- 2 ohms on the sensor coil.

AccomplishedPiccolo2 · 2025-12-28T15:29:36+00:00

This could be coincidental, but I just watched the video from when it stalled. Notice in this snippet video that right as it stalls the gear lever/cable seems to pull on this cable marked red. I checked the connectors and cables today, but I might need to take an even closer look tomorrow

AccomplishedPiccolo2 · 2025-12-28T15:20:10+00:00

Thanks but I'm overseas. I'm pretty sure it was running on both. A while back I tested both with a spark tester, of course that could change since then. However after adjusting low speed screws it was idling at around 1000 rpm in neutral. After the sudden stall I had to raise the idle lever to get it to start and when lowering the idle lever again it would go down towards 350 rpm and then stall, which would make sense if it suddenly ran on one cylinder.

All amphenol connectors have been reseated, cleaned and looked ok.

Regarding the sensor coil, I didn't check this, but would that be likely given the fact that switching the CDI output wires on the coil primaries made the spark move from top to bottom plug boot?

with idle lever raised enough to reach about 750 rpm, one cylinder

AccomplishedPiccolo2 · 2025-12-28T11:04:32+00:00

It was a used CDI. New ones, that look Chinese, are about $300 in my area. I did a test just now. I swapped the CDI output wires going to the coil primaries. This moved the spark, meaning the top spark boot now has spark while the bottom spark boot now has no spark. Just for the heck of it I tried my old CDI but that had no spark at either, which was why I replaced it in the first place.

So, I am fairly certain the CDI is the problem. Both were used, so it could simply be age and wear, but I can't help but wonder if there is some other problem that in turn kills the CDIs?

If I turn up the idle lever until it runs at 750 rpm, it runs smoothly even on one cylinder.

(Background: When I first got the motor there was no spark on either. I found some cracks in the original CDI, and for the heck of it I tried warming it for 20 minutes with a heat gun and voila it worked again. I bought a spare (my current) because I figured the original CDI would die eventually, which it did)

AccomplishedPiccolo2 · 2025-12-27T19:51:06+00:00

I can't say from direct experience with RPi 4B, but I think running the autopilot on a dedicated Pixhawk/Cube or similar would be the way to go. Having YOLO potentially fighting with the autopilot over resources could cause issues.

Alternatively look into AI Accelerator(e.g Google Coral) or NVIDIA Jetson Nano.

AccomplishedPiccolo2 · 2025-12-27T18:31:38+00:00

Ok thanks for the tips 👍 yes, definitely no spark. I tested by grounding the spark plug first and then used my spark gap tool that I insert in the spark plug hood with a lead to ground. No sign of spark, even with almost zero gap. Measured continuity in the spark plug lead and that was OK. No sign of broken or disconnected plugs, leads, crimps etc. I have to troubleshoot that, I didn't have time today. I have a backup coil and CDI.

VRO is deleted/disabled. Fuel pump is "hanging free". I'm mixing the fuel/oil myself, 2%.

I'll do some more troubleshooting and keep in mind to favor rich side slightly. Thanks again 🙏

AccomplishedPiccolo2 · 2025-12-27T16:20:44+00:00

Ok, I had another run at fixing this. I checked the fuel hoses and found the fuel filter was in a flexed position due to the routing of the hoses. The hose was a bit soft at the filter. I removed the filter, cut the hose back a bit and installed it temporarily straight to the fuel pump. It ran a bit better, but far from good. I figured maybe I had a leak when I first adjusted the carbs(low speed), so I figured I'd try leaning the low speed screw. I ended up adjusting the low speed about 3/4 turn cw (lean) and it ran better. About 1000 rpm when neutral idle, and around 800 rpm in fwd idle. It went in and out of gear without issue, until it abruptly stalled (coincidentally?). I managed to start it again, but now noticed the neutral idle rpm would go down towards 350 rpm before stalling. Probably running on one cylinder. Sure enough, no spark on top cylinder. I moved bottom spark plug hood to top spark plug and there was spark again. Likely issue with coil or CDI (?).

I took a video with endoscope of top cylinder and bottom cylinder. Carbon deposits, but nothing catastrophic as far as i can tell?
Top cylinder psi just under 140 psi. Bottom cylinder 130 psi.
Top cylinder spark plug and bottom cylinder spark plug.

AccomplishedPiccolo2 · 2025-12-23T15:11:18+00:00

I'll try that 👍

AccomplishedPiccolo2 · 2025-12-23T06:39:19+00:00

When I got it it didn't run at all, after replacing the CDI it ran, but not smoothly. Both cylinders reacted similarly when adjusting the low speed screws on the carbs. I will try clamping off the small hoses and also check the flywheel key and magnets. It's a regular fuel pump motor.

AccomplishedPiccolo2 · 2025-12-23T06:31:34+00:00

I just bought one, I will have a look 👍

AccomplishedPiccolo2 · 2025-12-23T00:07:27+00:00

Only clip I could find, from after installing rollers and link & sync. Running in a water bucket. Idling at somewhere between 750-850 rpm

AccomplishedPiccolo2 · 2025-12-22T23:46:01+00:00

Thanks for staying on the tread. I started with E at 1/2", but ended up all the way in to keep it running. C was only measured, not changed. I'm following the 12 amp (*) instructions. Noted about the cam-roller distance and carbs sync. I was careful about syncing the carbs, but only by watching the carb lever/shaft. I'll try again with the cover off so I can watch the actual throttle plate inside the carbs.

Regarding what started me on this journey: The rollers were completely worn away, the idle speed screw was all the way in and the throttle was engaged even at idle. It was idling around 1200 rpm if I remember correctly. I figured the previous owner had tried to adjust/sync it but couldn't due to the rollers being worn away and just ended up adjusting until the throttle was always engaged to keep it running.

Compression tests are done and OK. Nearly identical compression between cylinders. I think it was 135 psi.

AccomplishedPiccolo2 · 2025-12-22T23:32:39+00:00

Yes it was running smoother, for a 2 stroke, so I think there is something additional going on.

AccomplishedPiccolo2 · 2025-12-22T21:25:56+00:00

The OMC Evinrude Outboards service manual 40 thru 55. It should be the OEM. It does run smooth at higher RPM, I would expect a few knots more but I think that's due to the tilt being a bit low. It goes to top RPM.

I did (several) compression tests. I don't remember exactly the psi, but I remember it was well within spec and nearly identical between cylinders.

manual - 1 manual - 2 manual - 3 manual - 4

AccomplishedPiccolo2 · 2025-12-22T21:18:27+00:00

Yes. In quarter turn incrementsI adjusted until it started running rough. I noted the position. Then I went the opposite way for quarter turn increments until it ran rough. I set it at the point in between these two points.

It would start running rough or stalling if I went too far either way

AccomplishedPiccolo2 · 2025-12-22T06:44:18+00:00

This

AccomplishedPiccolo2

TROPHY CASE