[3v0]

Briggs has engines from 15.5HP to 18.5 or maybe higher that are all 31ci Intek engines. Does anyone know how they differ ?

 

[Whirly]

Briggs has engines from 15.5HP to 18.5 or maybe higher that are all 31ci Intek engines. Does anyone know how they differ ?

they get the extra hp thro the carbs & the grind on the cams.. basically they r the same block & bore.. same crank too..

 

[Walt 2002]

they get the extra hp thro the carbs & the grind on the cams.. basically they r the same block & bore.. same crank too..

Well actually the newer 31 series used a different block, piston & rings, counter weight system and sump.

Walt Conner

 

[suspicionofignorance]

Think I've interchanged few carbs, and cams, in that HP range.....Always wondered what bore size would equal what HP ? Or --- if there really was a change.? How the heck would I ever know..?

 

[Walt 2002]

Think I've interchanged few carbs, and cams, in that HP range.....Always wondered what bore size would equal what HP ? Or --- if there really was a change.? How the heck would I ever know..?[/QUOT

Well 31 denotes engine displacement, 31 cubic inches. Bore and stroke of ALL 31 series engines are the same regardless if they are called 15.5 hp or 21 hp. .

Walt Conner

 

[suspicionofignorance]

Dah....really feel dumb now...didn't know BS marked it off in Cubic inches...Anyhow, I never saw any difference in power when swapping carbs, and at least one cam in/out of that series...Ex: If I had a spare carb from a 16hp and reused it on the 21hp...or visa/versa...Should I have noticed power change? Think I actually have interchanged 28 series carbs too...! That woulda obviously changed the CID...Maybe I just didn't have a good test in using them to feel power changes..?

 

[3v0]

FYI: I was wondering if the shrouds from the 33ci would fit a 31ci. The stroke is the same so I expect it will.