The pilot in a Stanley is extremely important. Without it you have no source of ignition for your main burner which can lead to a lot spent on the side of the road relighting and an overwhelming sense of uneasiness when operating the vehicle. It is with that mind set I have put together this information.
The Packard Pilot vs the Stanley Pilot
First thing first the Packard pilot is not the exact same as the Stanley unit. They are very close but they are not identical. I'd learned this in a conversation with Don Bourdon (Bourdon Boiler Works) . The primary difference is in the adjustment adjustment needle. A Packard pilot operates with a long adjustable needle that actually seats in to the nozzle. It's much like the mixture adjustment on a brass era carburetor, if you tighten it in all the way you can actually stop the flow of fuel. The original Stanley operates with a different needle and seat adjustment. The needle has a flat on one side that is used to control the amount of fuel sprayed. It does not have the range of adjustment that the Packard unit has and the flat portion of the needle really meters the amount of fuel being consumed.
Lighting the Pilot
The key, literally, to getting a Stanley running is getting the pilot lit. You heat the pilot vaporizer with a torch until it reaches temperature to vaporize the pilot fuel. Once at temperature you cycle the pilot fuel valve until the pilot burner ignites. The ideal flame is yellow tipped that is just lifting off the burner grate. Original Stanley documentation says to always run the pilot as high as possible with little concern for consumption of pilot fuel. I believe it is a good practice as long as it doesn't smoke.
Flooding
Flooding a the pilot can happen any time you spray an excess amount of fuel into the pilot burner that cannot be burned. The fuel will collect in the pilot burner casting and overflow into the burner pan. This can happen rather quickly and isn't always apparent to the operator. Once you have a collection of raw fuel in the burner pan that ignites you have no choice but to shut off the pilot valve and let the fire burn out. In extreme cases the flaming liquid can drip out of the burner pan onto the front axle and strut brace. It is also usually common to have fire right at the tip of the pilot seat. The key to dealing with this type of fire is controlling any further addition of fuel and keeping calm. With that in mind I always wind the pilot adjustment completely closed. The needle valve isn't supposed to be a shut off valve but extreme situations call for extreme measures. This will stop the residual fuel in line between the needle valve and the pilot shutoff valve from adding to the fire. This type of flooding can happen when you are starting the Stanley from cold or if the pilot fails to vaporize fuel when driving. The major causes of flooding are using a fuel that is not able to vaporize completely with the heat provided or having the needle valve to far open thus causing the same vaporization issue.
Adjustment
There are really only three adjustments the operator can make on the pilot assembly. The first is to adjust the amount of fuel that is coming out of the nozzle by turning the needle valve. The second is to slide the pilot vaporizer forwards and backwards over the burner casting thus moving the H casting and modifying the air fuel mixture. The third is to adjust the fuel pressure that is feeding the pilot. A strong reliable pilot is a result of the best balance of these three adjustments. I'd like to start by providing my adjustments that have seemed to be working very well.
- I run the needle valve one and a quarter to one and a half turns open. Two full turns is to much!
- My vaporizer is in, over the pilot burner as far as it will go .
- My fuel pressure is at 10psi
- I'm running Hexane as a fuel that boils at 68.7 degrees Celsius
In Conclusion
The pilot is the key of a good operating Stanley. Don't try to mixing or changing fuels and expect all of your adjustments to stay the same. Be prepared to take the time needed to get things right and you'll have many years of happy touring.