# MTH Smoke unit wick repair



## Krieglok (Sep 7, 2013)

I am working on a MTH Premier NKP Berkshire. It is a PS-2 system with 3v boards. It has a lazy smoke unit...makes smoke but doesn't "fan" up out of the stack.

I took the smoke unit out and found the wicking was melted or burned where it touched the resistors. I figure the wick needs replacing. 

In a search here, the use of tiki torch wicking is suggested as a replacement. 

What length should the wicking be cut to and how much wicking should I use?

Tom


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## gunrunnerjohn (Nov 10, 2010)

This is a classic symptom of the impeller slipping on the motor shaft. If the smoke works at idle when it's continuous smoke and doesn't work when chuffing, it's the impeller slipping. You can put a drop of CA adhesive on the shaft to fix it, just don't let the glue get down into the motor or you'll cement it stopped.


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## HarborBelt1970 (Sep 24, 2015)

If you are not getting smoke up through the stack in quantity with an MTH PS2 engine I suspect your problem is not only the wicking. 

I just serviced one of my PS2 conversions with some MTH rope wicking I got on eBay, which made a fair amount of difference to the output but in addition (a) cranking the DCS smoke setting up to high makes a big difference and (b) you do not need to try and cram the whole wicking rope into the smoke chamber. The wicking needs to be no more than about 3.5" in length and you must not block the U-shaped channel between the fan housing and the reservoir.

There have been varying reports about using Tiki Torch wicks and I have avoided them in favor of material specifically intended to be used in model train smoke units. With MTH units you are meant to put a loop of the wicking material in between the dual resistors, which ensures that they will char even if (as you should also do) the wicking is saturated with smoke fluid. 

I've also found in my PS2 engines that they came stock with two fairly short lengths of wicking used together in the manner described above. I've duplicated that when servicing my engines.


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## Krieglok (Sep 7, 2013)

Hmm. The engine was making decent smoke before I opened it up. I saw the wicking was charred into a hard blob, but it worked. I pulled it out anyway...ugh.

Anyway, tha lazy smoke and loose fan correlation is something I never thought of. I will use John's advice and ACC it when I install the now needed wicking. Thanks again for the tech advice, John.

Harborbelt, your advice sounds good to me too. I will look for the proper wicking. Thanks for the pointers on installing the wicking too.

Tom


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## Krieglok (Sep 7, 2013)

I did a little work on my new/old Berkshire today. I removed the smoke unit and checked the impeller and it slid right off the shaft. I cleaned the impeller pocket with alcohol and set a couple drops of ACC in the impeller hole and reinstalled it. I let is sit for a while then tried tugging it again and now it is well adhered to the motor shaft. It turned easily though, so thanks to John, that issue was solved.

Next I turned to the wicking issue. I ordered a few MTH wicks on line but my obsessive compulsiveness got the best of me. I stopped off at the hardware store and bought the last package of Tiki Torch wicking. 

Using a technique shown in a You-Tube video, I repacked the fluid chamber with new wicking. The method differs a little from the MTH method, but it seemed to be working in the video.

I wet the wick thoroughly and then installed the unit top. Then I rechecked the impeller and installed that. The whole assembly went back into the boiler and I put the engine back together.

I added a bit more smoke fluid and started the engine up. It took a minute, but the smoke started working well. It improved as I let it idle for a while.

In conclusion, I figure the MTH method of wick installation likely works better than the YT method, but for now the engine puts out decent smoke.

Tom


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## gunrunnerjohn (Nov 10, 2010)

Smoke is the desired end result.


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## Krieglok (Sep 7, 2013)

Just need to fix the front markers now...it never ends! Lol

Tom


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