B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

G

GreenAdam

Forum Newbie

Joined

Apr 30, 2016

Threads

1

Messages

2

• May 1, 2016 / B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

• #1

Hello. I have a John Deere LA120 riding mower with a Briggs Model 44 V-Twin that is rated at 21 horsepower. I've always felt like the mower could use a little bit more power. Just for kicks, I was doing some poking around online tonight and noticed that the next "bigger" John Deere in this series was the LA140 that was rated at 23 horsepower. Digging a little deeper, I noticed that both engines have a displacement of 724 cc. And then I noticed that they have identical bore and stroke dimensions as well.

Does anyone know what the actual difference is between these engines? Is the 21 horsepower version just have slightly lower compression, different carbs, or maybe just detuned in some way? It's obvious where I'm going with this - I want to unleash those 2 extra mystery ponies!!

 

B

bertsmobile1

Lawn Royalty

Joined

Nov 29, 2014

Threads

64

Messages

24,702

• May 1, 2016 / B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

• #2

Re: B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

Main jet & govenor springs

 

G

GreenAdam

Forum Newbie

Joined

Apr 30, 2016

Threads

1

Messages

2

• May 1, 2016 / B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

• #3

Re: B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

bertsmobile1 said:

Main jet & govenor springs

Click to expand...

Really? That's all? Any idea how I could track down the part numbers required to make the swap?

 

B

bertsmobile1

Lawn Royalty

Joined

Nov 29, 2014

Threads

64

Messages

24,702

• May 1, 2016 / B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

• #4

Re: B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

You can download the parts books and check the numbers.
However it is not some sort of gift from heaven.
The actual Hp of the motors is nothing like what is on the sticker and 1 Hp or 2 Hp extra will make diddly squat difference other than using more fuel
The mower still spins at 3600, it dont go any faster and the supposed extra Hp will be neglegable.
You will not notice any difference unless you regularly run it through 4' tall weeds.

 

T

Tinkerer200

Well-Known Member

Joined

Mar 14, 2015

Threads

4

Messages

913

• May 1, 2016 / B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

• #5

Re: B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

Well I don't think governor spring has anything to do with it. This is not at all unusual for B&S with several engines varying 4 hp or more using the same basic engine. Actually, the 44 series engine is more often called 24 - 26 hp. The 40 series V twin is in the range you mention.

Walt Conner

 

B

bertsmobile1

Lawn Royalty

Joined

Nov 29, 2014

Threads

64

Messages

24,702

• May 1, 2016 / B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

• #6

Re: B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

Tell that to my box of govenor springs.
Sometimes the Hp is clipped by dropping a few hundred revs off the top end.
Some times it is a bigger main jet
Some times both.
And although I have never bothered to measure them I have a sneaky that the top Hp in a set uses the carb from the next size up set.
A 0.5mm increase in the carb bore make a big difference to the top end.
A lot of motorcycle factories did the same thing.
I do work on a couple of race mowers, nothing too serious , you know , just have to get one up on their mates, but down here we only seem to run singles.

 

T

Tinkerer200

Well-Known Member

Joined

Mar 14, 2015

Threads

4

Messages

913

• May 1, 2016 / B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

• #7

Re: B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

Virtually all B&S engines are rated for max. hp at 3600 rpm. Sure you can change that by varying the governor spring and thus the top rpm but that is not rating them on equal basis, don't give a hoot about motorcycles. Main difference in hp is what sticker the equipment mfg. wants slapped on them which is why B&S lost the big hp law suit. Of course different models and different brands require different springs.

Walt Conner

 

B

bertsmobile1

Lawn Royalty

Joined

Nov 29, 2014

Threads

64

Messages

24,702

• May 2, 2016 / B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

• #8

Re: B&S Model 44 V-Twin engines w/ same displacement but different horsepower - ???

We had a locl manufacturer done for a similar reason.
Apparently it is OK to sell the mower with a sticker that says less Hp than the engine actually puts out.
Hower when it was advertised next season as " having a more powerful engine" they got done regardless of the fact the "new" engine was still putting out more Hp than it was labelled as.
The ruling went along the lines that the engines were the same but with different Hp on the lable and despite the engine being more powerful than stated it was missleading to say it was more powerful than last year.