Briggs Model NR6 Engine

Specifications on the Briggs and Stratton NR6:
The model NR6 was manufactured from 1940 to 1954 by Briggs and Stratton Corporation.
The serial number on the tag of this engine dates it to March, 1945.  
This particular model uses a rope start cup to start the engine. There were other mechanical devices were used to start the engine such as pedal, (foot start),  and lever starters.  
This engine used an L-head design, (also known as flat-head).
It is equipped with the adjustable pneumatic governor.
The air cleaner on this engine is an efficient oil-bath type. This engine has a 1 to 6 rear ratio gearbox that is integral with the engine crankcase, (cast as all one unit).  
The exhaust is aspirated through a 1/2" NPT threaded port.
Gas tank is mounted externally via steel straps connected to the head and to the cooling shroud. The oil sump and head are made of cast iron. The engine block is made of cast iron and utilizes fins for air cooling. The crankshaft is counter weighted and drop forged.
Displacement: 6.28 cubic inches,
2.00" bore and 2.00" stroke.
Rated at 1-1/2 horsepower, 2600 - 3600 rpm.
Lubrication: Pump or dipper type, (later exclusively dipper type was used).
Ignition: High tension magneto.
Spark plug size: 14mm.
Oil sump capacity : 2 pints.
Gas tank capacity: 4 quarts. 

Here is a Briggs and Stratton Model NR6 four cycle engine that I am in the process of restoring. I bought the engine off Ebay. At the time of purchase It was missing the intake manifold, carburetor, and air cleaner. The gas tank was rusted badly so I had to find a substitute for it also. The shroud was painted red, (which of course was not the original color of the engine). After replacing the missing parts and putting oil and gas in the engine I was having a difficult time trying to get the engine to fire. Upon going through the ignition and finding no problems, (had a nice snap of a white spark).  I noticed that the compression was on the low side. I also noticed that the oil was getting past the worn rings further hampering  a good fuel mixture for ignition. I managed to get the engine started to produce a video but in the not-so-distant future this engine will undergo a complete rebuild.  

Briggs and Stratton is the trade name of the Briggs and Stratton Corporation.
Published by MSPI © 2012. All rights reserved