How To Run a Pop Pop Motor

Pop pop, or putt putt boat engines have been around since the early 1800's. Their name comes from the noise these little engines make while running. To run the engine, it must first be primed. This is done by holding the nose of the boat down while squirting water in one exhaust pipe until it runs out the other pipe. (A squeeze bulb primer comes with all of our boats) Once primed, the boat must be placed in a pond, bathtub or even a pan of water. Light the candle or included oil burner wick and slide it under the boiler pan and your boat will start popping loudly and moving forward at a rapid pace.

Here's how it works:

The boiler filled with water has a heat source placed under it. The heat source begins to heat the water in the boiler until the first large bubble is "flash boiled". This eruption of steam and water is forced out the exhaust pipes, causing the boat to move forward. When the contents of the boiler pan are blown out, a vacuum is created in the sealed system. This causes water to be sucked back into the exhaust pipes and onto the hot boiler pan surface again. This causes another eruption of steam and water, and the cycle starts over. The motor will run as long as the heat source keeps the boiler hot. The "popping" sound is made by a .005" thick piece of shimstock that makes up the top of the boiler. This is called a "diaphragm" and it pops up and down with the cycles of the motor.

There is another type of flash boiler also. This consists of a coil of copper tubing with a heat source beneath it. The ends of the coil are the exhaust pipes. It is primed and run the same as above, but this motor is silent. These motors were used for propulsion in many of the early toy ships made by Sutcliffe.

Buzz's BoatYard does make custom coil boilers for small boat applications. Email us for more information.

Still have questions? Feel free to email us from any link on the site.

 

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