O.S.SPEED R21-M05 2024 Minicars Marine SE Racing 3.5cc Engine
![](https://www.minicars.se/dokument/bibliotek/Image/Loggor%20mm/OS-R21-M05-Minicars-Marine-SE-logo.png)
This is the new 2024-edition Minicars Marine Special Edition O.S.SPEED R21-M05 3.5cc long-stroke competition engine!
Features:
- 2024 Updates: New combustion chamber with smaller volume for low nitro & updated piston for easier run-in
- O.S.Speed developed black crankcase with Minicars Marine Laser Engraving
- Black anodized water cooling head with Minicars Marine Special Edition Laser Engraving
- DLC coated & balanced "SG-type" crankshaft (4.5mm balance weights)
- 9-port cylinder liner with 3-port exhaust
- Backplate with steel thrust plate for lower friction and increased durability
- No carb included - choose your own carburetor (15mm diameter neck)
Suitable for competition boats (experience level ”high”):
- Hydroplanes
- Offshore (with gear deduction)
- Endurance (with gear reduction)
Recommended fuel:
- Hydroplanes: 12-40% nitro fuel with 8% Klotz Original Techniplate + 8% Klotz Benol oil
- Offshore: 12-40% nitro fuel with 8% Klotz Original Techniplate + 8% Klotz Benol oil
- Endurance: 12-40% nitro fuel with 8% Klotz Original Techniplate + 8% Klotz Benol oil
- Don't run the engine with less oil than the above recommended levels. You may add more recin/castor oil (Klotz Benol) in extreme conditions and heavy loads.
Specs:
- Displacement: 3.49cc
- Bore: 16.08mm
- Stroke: 17.2mm
- Crankshaft dia: 14mm
- Practical r.p.m. Range: 4.000?43.000
- Output: 2.76hp @ 35.000r.p.m.
- Weight: 265g
- Water Cooling Nipple Thread: M5
Included:
- O.S.Speed R21M05 2024-Edition Minicars Marine Engine
- RP7 Glowplug
- O.S.Speed flywheel cone
- O.S.Speed decal
- Printed Manual & partslist
![](https://www.minicars.se/bilder/artiklar/zoom/OS0R21M05_14.jpg)
9-port sleeve with a 3-port exhaust (with updated 2024 piston for easier run-in)
![](https://www.minicars.se/bilder/artiklar/zoom/OS0R21M05_16.jpg)
DLC coated crankshaft with improved balance
![](https://www.minicars.se/bilder/artiklar/zoom/OS0R21M05_10.jpg)
Steel insert backplate for less friction and more durability
![](https://www.minicars.se/bilder/artiklar/zoom/OS0R21M05_11.jpg)
Marine cooling head with Minicars Marine laser engraving
![](https://www.minicars.se/bilder/artiklar/zoom/OS0R21M05-24_13.jpg)
New combustion chamber with smaller volume for lower nitro levels