Pull-start nitro boat guide

Radio Control Boat Modeler, Aug 2001

Nitro-powered, internal-combustion-engine craft are among the most exciting RC boats, and we've been designing, building and racing them for years. For many, these nitro-drinking wonders represent the pinnacle of the hobby, but they require additional support equipment and a certain mechanical savvy if they're to be maintained in proper working order.

Now a new breed of sport and ready-to-run (RTR) boats powered by small pull-start engines makes the excitement available to entry-level enthusiasts and sport boaters because they're easier to start. Gone are the hand-held electric starters, starter belts and heavy starter batteries (also gone is their additional expense). A simple rechargeable Ni-- Cd glow-plug driver, a few hand tools and a hand pump to fill the fuel tank are all you need to enjoy nitro-powered boats.

WHY NITRO POWER?

Compared with electric powered boats, pull-start nitro boats offer some advantages:

Longer run times. This is a major advantage. They run much longer on a full tank than electrics do on a full charge. On average, a fast electric boat will run from 4 to 6 minutes on a charge while a nitro boat will run for twice as long if equipped with a 10- to 12-ounce fuel tank. And if you want to run your boat more than once between charges, you need extra battery packs that can cost as much as $20 to $30 each; and you have to wait for them to cool off before you can recharge them at the pond. No cooling-down period is required with a nitro boat; as long as you set the fuel/air mixture correctly, you can run as often as you want simply by refilling the tank.

More exciting to watch and run. Admittedly, nitro boats are noisier than electrics, but for realism, that sound and the unmistakable smell of burning nitro fuel are really hard to beat!

The choice of nitro-powered boats is expanding quickly; almost every day, new RTR boats and kits appear on hobby shop shelves. Custom accessories, metal props and running hardware are also more readily available, and they help us increase the already satisfying speeds and performance afforded by these miniature powerboats.

This guide tells you what's available and what you should expect if you decide to take the plunge into nitro. From the very basic first-timer boat to high-performance raceboats, we've included all we could find. Get ready to start your engine and have some serious rooster-tail fun!

Every model engine requires the proper maintenance if It's to produce maximum power and last a long time. The best way to deal with nitro-engine problems Is to avoid having them in the first place, and proper maintenance is the key to this. These hints should keep your nitro engine happy.

BREAK IN. Before being run at max power, an engine must be broken in. Run your boat for several short cycles with the fuel/air mixture set very rich. Doing this will ensure that the piston and cylinder sleeve are worn in gradually and seat properly. By running the engine for several minutes and letting it cool before running it again, you can control the wear between the piston and sleeve surfaces. It you run your engine all out with that first tank of fuel, the engine and its internal parts will get very hot and expand. This expansion will lead to excessive friction between the parts, resulting in an even greater heat buildup to a point at which you can damage the piston/sleeve fit. This poor fit will mean a loss of compression. In the long run, the engine will be damaged and will never develop its full power output. Take the time to do it right; it will pay dividends later on.

POWER UP WITH NITRO. Nitro fuel is a mixture of methanol (alcohol), lubrication oil (synthetic or a mixture of synthetic and caster oil) and nitromethane (nitro). The largest component (base Ingredient) is methanol; nitro, oil and sometimes a dye are added to make model fuel. Nitro is used In full-size dragsters and funny cars; it has tremendous power potential. The higher a fuel's nitro content (usually expressed as a percentage), the higher the power output will be. Nitro fuel is also referred to as "glow fuel." You can find 10-percent, 15-, 20-, 30- and even 50-ercent and higher nitro blends. For general sport and fun running however, start with 10- to 15-percent nitro because it's the least expensive and the easiest to run.

The higher your fuel's nitro percentage, the more sensitive your engine's needle valve will be. Ten and 20 percent nitro will allow your needle-valve setting to be a few "clicks" off In either direction without the mixture's being too rich or too lean. As you gain experience, you'll be able to increase the nitro content and enjoy a commensurate increase In power.

LUBRICATE FOR LIFE. Pull-start nitro engines are 2-strokes and do not have a separate oil tank or a sump to help lubricate their parts. The lubricant (oil) has to be mixed with the fuel. You must choose a fuel that has the oil percentage recommended by your engine's manufacturer. If no recommendation is given, use a fuel with at least 18 percent oil. Most fuel container labels show the percentage of nitro and oil. Check these figures and save your engine from a short life and a cruel death.