Briggs and Stratton general-purpose engines model decode:

Example: 3-0-3-4-4-7

Symbol Modifications
30 Cubic inch displacement:
30 – 30 cu.in
3 Basic design series:
0-9
A-Z
4 Crankshaft orientation:
0-4 – Horizontal shaft
5-9 – Vertical shaft
A-G – Horizontal shaft
H-Z – Vertical shaft
4 PTO bearing, reduction gear, auxiliary drive, lubrication:
0 – Plain bearing/DU, Non-flange mount
1 – Plain bearing, Flange mounting
2 – Sleeve bearing, Flange mounting, Splash lubrication
3 – Ball bearing, Flange mounting, Splash lubrication
4 – Ball bearing, Flange mounting, Pressure lubrication
5 – Plain bearing, Gear reduction (6 to 1) CCW Rotation, Flange mounting
6 – Ball bearing, Gear reduction (2 to 1) CCW Rotation
7 – Plain bearing, Pressure lubrication
8 – Plain bearing, Auxiliary drive (PTO) perpendicular to crankshaft
9 – Plain bearing, Auxiliary drive parallel to crankshaft
A – Plain bearing, Pressure lubrication w/o oil filter
4 Type of starter:
0 – Without starter
1 – Rope starter
2 – Rewind starter
3 – Electric starter only (110V or 230V), Gear drive
4 – Electric starter (110V or 230V), Gear drive with alternator
5 – Electric starter only (12V or 24V), Gear drive
6 – Alternator only
7 – Electric starter (12V or 24V), Gear drive with alternator
8 – Vertical pull starter or side pull starter
9 – Mechanical starter
A – Electric starter (12V or 24V), Gear drive with alternator and inverter
Engine Displacement Power output (max.)
Single-cylinder
252707 399 cc (24.35 cu.in.) 11.0 HP at 3,600 rpm
253707 399 cc (24.35 cu.in.) 11.0 HP at 3,600 rpm
281707 465 cc (28.4 cu.in.) 12.0 HP at 3,600 rpm
282707 465 cc (28.4 cu.in.) 12.0 HP at 3,600 rpm
286707 465 cc (28.4 cu.in.) 12.5 HP at 3,600 rpm
289707 465 cc (28.4 cu.in.) 12.5 HP at 3,600 rpm
28M707 465 cc (28.4 cu.in.) 13.0 HP at 3,300 rpm
28N707 465 cc (28.4 cu.in.) 15.5 HP at 3,300 rpm
28Q777 465 cc (28.4 cu.in.) 15.5 HP at 3,300 rpm
28R707 465 cc (28.4 cu.in.) 13.5 HP at 3,300 rpm
28S777 465 cc (28.4 cu.in.) 13.5 HP at 3,300 rpm
310707 501 cc (30.6 cu.in.) 16.5 HP at 3,600 rpm
311707 501 cc (30.6 cu.in.) 16.5 HP at 3,600 rpm
311777 501 cc (30.6 cu.in.) 17.0 HP at 3,600 rpm
31A607 501 cc (30.6 cu.in.) 15.5 HP at 3,600 rpm
31C707 501 cc (30.6 cu.in.) 17.5 HP at 3,600 rpm
31E777 501 cc (30.6 cu.in.) 16.0 HP at 3,600 rpm
31F707 501 cc (30.6 cu.in.) 17.0 HP at 3,600 rpm
31G777 501 cc (30.6 cu.in.) 17.5 HP at 3,300 rpm
31H777 501 cc (30.6 cu.in.) 18.0 HP at 3,600 rpm
31N707 501 cc (30.6 cu.in.) 18.5 HP at 3,600 rpm
31P777 501 cc (30.6 cu.in.) 18.5 HP at 3,600 rpm
31P977 501 cc (30.6 cu.in.) 20.0 HP at 3,600 rpm
31Q777 501 cc (30.6 cu.in.) 18.5 HP at 3,300 rpm
31R777 501 cc (30.6 cu.in.) 15.5 HP at 3,300 rpm
31R977 501 cc (30.6 cu.in.) 17.5 HP at 3,600 rpm
331777 540 cc (32.9 cu.in.) 20.0 HP at 3,600 rpm
331877 540 cc (32.9 cu.in.) 21.0 HP at 3,600 rpm
Two-cylinder
294447 480 cc (29.3 cu.in.) 14.0 HP at 3,600 rpm
303447 495 cc (30.2 cu.in.) 16.0 HP at 3,600 rpm
303777 495 cc (30.2 cu.in.) 16.0 HP at 3,600 rpm
350447 570 cc (34.8 cu.in.) 18.0 HP at 3,600 rpm
386447 627 cc (38.2 cu.in.) 21.0 HP at 3,600 rpm
400707 655 cc (40.0 cu.in.) 16.0 HP at 3,600 rpm
402437 655 cc (40.0 cu.in.) 16.0 HP at 3,600 rpm
402707 655 cc (40.0 cu.in.) 16.0 HP at 3,600 rpm
422447 694 cc (42.3 cu.in.) 18.0 HP at 3,600 rpm
422707 694 cc (42.3 cu.in.) 18.0 HP at 3,600 rpm
42A707 694 cc (42.3 cu.in.) 18.0 HP at 3,600 rpm