The NEW O.S. MAX .15 CV-M
The O.S. MAX .32 SX-MX Pull Start
The O.S. MAX .21 XM
Nitro Engines - (or glow engines) are great! They are small and make lots of Horsepower (HP or BHP). They come in many different sizes (displacements) for the different modelers requirements. For example in or out board mounted. Engines up to .32 are available with a pull start. They run on 10-60% Nitro laced fuel designed especially for Radio Controlled models. Engine size is measured 2 ways; by cubic centimeter (7.5cc) or cubic inch (.46 cu.in.). So a .10 engine (1/2HP) is small compared to a .90 engine (5HP).
O.S. Max makes some of the best engines in the world with good power and great reliability! OPS, Picco, Rossi and K&B engines are also very popular with R/C boaters.
Nitro engines can turn very high RPM and should be carefully handled and maintained from any contaminants (dirt & water) getting into the engine. However, the engines are easy to rebuild too. See tuning more more information on setting the fuel mixture properly.
| The NEW O.S. MAX .15 CV-M |
The O.S. MAX .32 SX-MX Pull Start |
The O.S. MAX .21 XM |
| O.S. Engine | Bore (in) |
Stroke (in) |
RPM | Output (BHP@rpm) |
Weight (oz) |
|---|---|---|---|---|---|
| 15 CV-M (OSMG1618) |
0.598 | 0.539 | 3,000-25,000 | 0.60 @ 15,000 | 5.89 |
| 15 CV-MX (OSMG1619) |
0.598 | 0.539 | 3,000-25,000 | 0.60 @ 15,000 | 5.89 |
| 21 RZ-M (OSMG1621) |
0.654 | 0.630 | 3,000-40,000 | 2.40 @ 32,000 | 13.03 |
| 46 VX-M (OSMG1647) |
0.866 | 0.772 | 2,500-28,000 | 2.50 @ 28,000 | 15.70 |
| 61 VR-M (OSMG1662) |
0.945 | 0.866 | 2,500-25,000 | 2.80 @ 22,000 | 32.12 |
| 65 VR-M (OSMG1667) |
0.976 | 0.866 | 2,500-25,000 | 3.00 @ 22,000 | 32.23 |
| 81 VR-M (OSMG1681) |
1.024 | 0.965 | 2,500-25,000 | 4.20 @ 22,000 | 32.30 |
Nitro engines usually drive a
very light and efficient boat. Flex drive has been around for several years but,
is still the greatest. Flex drive cable is available in left or right
"wrap" although left is most common. This is because the flex is
directly attached to the engine's crankshaft which turns left while the engine
is running.
Flywheels are important but not usually included with your Nitro engine. All are
directly attached to the crankshaft and most are centered on a tapered sleeve
(as shown in Fig 1). The flywheel is then compressed onto the taper with a Flex
Hex Assembly that is threaded on the remaining threads of the engines crankshaft
(as shown in Fig 2).
Figure
1
Figure 2
Water in the Engine
I'm not talking about water cooling either! This happens all the time with a boat. First, dump all the excess water out of
your boat. Then simply take out the glow plug and spin the engine over with the
electric starter. NOTE:
be sure to loosely cover the glow plug hole with your hand, as a combination of
water and Nitro will spit out! You do not want it in your face.
Retest the glow plug to make sure it still glows. They often burn out when the cold water hits them. Replace if necessary. IMPORTANT: Always restart your engine after water has been in there. There is still enough water in the engine to rust the internal parts. Once run the moisture is burned and replaced with oil in the Nitro fuel.
It is always a good idea to protect your investment with "after run" oil too.
See Starting for more information on "how to" start your engine.
See our Links for great places to buy an engine.
Nitro engine to hull size guide
Brand by size Recommendations - coming soon!