Am I as stupid as I think I am?

#1
I dont want to ask this, for fear of making a clown of myself. But here goes. Are Briggs 3hp's the same crankcase size as Briggs 5hp's? Also, did Briggs 3hp engines ever have governors? Mine doesn't seem to...
 

old shed finds

Well-Known Member
#3
The dimensions are smaller on a 2-3 hp compared to a 4-5 hp block. The governor was an external air vane under the shroud on the small 2-3 hp engines.
Markus is right on...
And a 4hp block is rare hard to find..5s are common as the moon.. And both the 4 and 5 have internal gear spun governor. ..
 

dshot59

Active Member
#5
So which is more rare the small or the big ? I have an 86 4hp and it is smaller then the 5 for sure I tried the pull start cover from the 5 on the 4 and it was larger.
 

Attachments

markus

Well-Known Member
#6
So which is more rare the small or the big ? I have an 86 4hp and it is smaller then the 5 for sure I tried the pull start cover from the 5 on the 4 and it was larger.
the physically smaller sized 4hp 110000 series engines are of a later era, I dont know how "rare" they are but they were not something found or around during the typical vintage mini bike time frame. even in the 80's and 90's in the catalogs from kart/minibike dealers that I have they didn't mention or offer that particular engine still for some reason, still just the 80000 and the 130000 (3 and 5hp the larger 4hp was gone and off the books by then) the the 100000 4hp of the mini bike era were the same outside dimensions as the 5hp, with smaller guts internally, Later 110000 are sort of in between when it comes to physical exterior dimensions of those.
 

pomfish

Well-Known Member
#7
Markus,

Did any mini bikes come with the big block 4hp as standard or optional equipment?
I have a Copper colored big block 4hp but not sure where I got it.
Also have a White one which came off a rototiller

Also in your B&S tech manuals, what were the highest rpm governors used and on what applications if known?
Thanks!
Keith
 
#8
Markus,

Did any mini bikes come with the big block 4hp as standard or optional equipment?
I have a Copper colored big block 4hp but not sure where I got it.
Also have a White one which came off a rototiller

Also in your B&S tech manuals, what were the highest rpm governors used and on what applications if known?
Thanks!
Keith
Our Ken-Bar Whirlwind had a 1998 H40 on it when we got it.
 

markus

Well-Known Member
#9
Markus,

Did any mini bikes come with the big block 4hp as standard or optional equipment?
I have a Copper colored big block 4hp but not sure where I got it.
Also have a White one which came off a rototiller

Also in your B&S tech manuals, what were the highest rpm governors used and on what applications if known?
Thanks!
Keith
Fox, and KOL made bikes used a 4hp, there were others as well. Not sure why they would choose it over a 5hp, but I honestly dont know the History of the briggs 5hp powerplant, when it came into play, availability in the earlier years, etc..

could not tell ya on the governors, I am sure you could search around on the internet and maybe find some specs but I stick mainly to the Tecumseh literature. they (Tecumseh) really didnt vary their govenor settings too much between equipment until the later years, they started lighting up the gov on the Recreationals over the say snowthrowers by a few hundred RPMS.
 
#10
Hello,
I remember reading some years ago, that B&S stopped providing mini bike power plants in the very late 60's. Maybe early 70 at the latest due to a law suit. Tecumseh became the std. engine after that. If memory serves correct. Not sure.
Regards,
Joe51
 

Divouneh

Active Member
#11
Hi Markus
"The dimensions are smaller on a 2-3 hp compared to a 4-5 hp block. The governor was an external air vane under the shroud on the small 2-3 hp engines. "
It explain me why I don't find any actuator coming out from my 2.5HP casing. I have a wire going to the carburetor: seems to shortcut the ignition in
high speed or zero position ?

Switch off.jpg
 

markus

Well-Known Member
#12
Hi Markus
"The dimensions are smaller on a 2-3 hp compared to a 4-5 hp block. The governor was an external air vane under the shroud on the small 2-3 hp engines. "
It explain me why I don't find any actuator coming out from my 2.5HP casing. I have a wire going to the carburetor: seems to shortcut the ignition in
high speed or zero position ?

View attachment 259624
its a stop switch, its not a mini bike engine, probably off a piece of equipment originally. when you went to idle it would cut the engine off if all the pieces are still there. use your model and type numbers to find the parts list for it 80102-0135-01
 
#14
The 3 hp engine's governor is an air vane that is externally mounted on the block. From what I have read the 3 hp is smaller than 4-5 hp engines. So the 3 hp is smaller and doesn't have a hole in the block for the mechanical governor.
 
Top