21XZ-M Inboard Marine Engine

A proven on-road powerhouse comes to the boating world!

Based on the 21XZ-R - Performance at the 2011 IFMAR 1/8 scale On-Road World Championships — the 21XZ-M Inboard Marine Engine takes that race-winning technology and applies it to dominating .21-size boat competition! Many of the performance features found on the 21XZ-R are here; and by utilizing a water-cooled cylinder head and big-bore carb, the 21XZ-M will assert itself on the water with the same resounding success!

21D big-bore carburetor
21D big-bore carburetor
cylinder head
Water-cooled, blue anodized cylinder head
  • Specifications
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Stock Number: OSMG1621
Displacement: 0.21 cu in (3.5 cc)
Bore: 0.640 in (16.27 mm)
Stroke: 0.661 in (16.8 mm)
Practical rpm: 4,000-45,000
Output: 2.71 hp @ 33,000 rpm
Weight: 10.85 oz (307.5 g)
Includes: 21D carb, RP7 turbo plug, flywheel collet, 0.2 mm head gasket, dust caps
Requires: 10-30% nitro boat fuel (20% recommended for break-in), exhaust system, glow plug igniter

NOTE: Do not use car or truck fuels; use fuels designed for boat use

Recommended Product
AQUP2230 AquaCraft® Models 30% Boat Fuel (Quart)
AQUB6903 AquaCraft Models 3" Fuel Line (3/32" id, 3/16" od)
AQUP2250 AquaCraft® Models 50% Boat Fuel (Quart)
AQUB9720 GrimRacer™ 40 x 52 Tri-Metal Propeller
AQUB9715 GrimRacer 40 x 53 Tri-Metal Propeller

Recommended Options
Note: items marked with an asterisk (*) are included.
OSMG2704 RP7 Turbo Glow Plug Cold*
OSMG2703 RP6 Turbo Glow Plug Medium
OSMG2715 RP8 Turbo Glow Plug Cold
OSMG8876 Exhaust Coupler .21
OSMG5872 Super Can Filter Large
OSMG9401 Lock Washer 3mm
OSMR2977 O.S. Speed Plug Wrench
OSMR3000 O.S. Speed 10-Piece Tool Set

See your local hobby dealer for additional recommendations.

Primary Accessories

Stock Number Mfr Number Product Description Quantity Needed
 GPMQ4131   GPMQ4131  Great Planes Silicone Fuel Tubing Standard 3' 1

Field Equipment

Stock Number Mfr Number Product Description Quantity Needed
 DTXP0310   DTXP0310 Duratrax Ultimate Glo-Starter C 1
 OSMR2976   71521000 O.S. Long Socket Wrench With Plug Grip 1

Optional Accessories

Stock Number Mfr Number Product Description Quantity Needed
 ODOP3030   ODOP3030  O'Donnell 30% Boat Gallon 1
 ODOP3130   ODOP3130  O'Donnell 30% Boat Fuel Quart 1
 OSMG5872   72403050  O.S. Super Can Filter Large 1
 OSMG8876   72106300  O.S. Exhaust Coupler 21 1
 PAAP1453   PT31  Pacer Zap After-Run Engine Oil 1 oz 1
 SULP1826   S626  Sullivan Starter Belt Boats/Heli 1