Could someone advise me on the safe amount of smoke fluid to put into an MTH PS 3 O scale diesel locomotive, >? thankyou
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First of all turn on the smoke system, and run the engine until the smoke output is very light. Then it would be safe to put in 15 drops of fluid.
If it is new, add the fluid before you turn it on for the first time. The manual usually has instructions.
The general rule is 15 to 20 drops on a new smoke unit and let it saturate for a few minutes before turning on the smoke. When the smoke diminishes, add another 10 to 15 drops. I usually add a few drops if the loco goes into storage for a while and will add about another 10 drops after it is taken out of long-term storage before running it.
NEVER RUN A SMOKE UNIT DRY OR WITHOUT FLUID.
My experience is that a new dry smoke unit needs well over 20 drops. A new smoke unit gets about 2/3 of a JT's MegaSteam dropper, that equates to 35-40 drops. Then I add about 20 drops when the smoke volume drops off during running.
What gunnerjohn says!
Ron
GRJ,
How big should each drop be?
Gunny
I don't try to "size" drops, I just use a set amount in the MegaSteam dropper. When I rebuild smoke units and have new dry wick, it typically takes several droppers to thoroughly soak the wick material. This is still little enough fluid that I can hold the smoke unit upside down and nothing leaks out.
There is such a thing as Too much of a good thing, certainly too much smoke fluid is bad as well. However, most manufacturer's instructions err on the side of too little fluid. I get it, as I've seen stuff come in inundated with smoke fluid all over the place, that's not good either.
The key here is balance. The experience of having hundreds of smoke units apart over the years has given me a pretty good gauge of how much fluid to use.
Another point is that certain smoke units are different sizes. Specifically, MTH whistle steam and small diesel smoke units are much smaller than the "standard" smoke unit. Those are good with 15 drops of fluid, they have a much smaller capacity. You have to know what you're dealing with.
I've had a few cases where I did as GRJ said and added 30 drops of fluid to prime new locomotives, let it sit for a few minutes but fluid ran out after turning it over. I suppose the smoke unit could have used a little more wick from the factory. I just go by what is in the user manual which in most cases states 15 - 20 drops to prime.
@H1000 posted:I just go by what is in the user manual which in most cases states 15 - 20 drops to prime.
Being the smoke go-to guy for a lot of folks, I get a lot of complaints about following the manual and then not having decent smoke production. But if it works for you, who am I to complain. 
I've done 30 to 40 drops in a new dry unit. 10 drops at a time every few minutes allowing it to soak in and prime the wicking. I usually get good smoke for 5 minutes or so and then add 10 to 15 drops as needed after cooling down a minute or so. If it sits for a few days or weeks I start the process over.
Brad
thank you very much
