# 5hp briggs and startton mods?



## zseverns (Mar 17, 2011)

does anyone out there have a 5hp briggs and stratton that might have done some type of performance upgrades on this motor? if so i would love to know what they are and how to do them. any help would be great. i like this little motor it isn't fast by no means but it gets me to where i need to go but if there is anyway to get more power out of it i would sure like to.


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## PartsMan (Mar 17, 2011)

I am sure that you could do some of the tricks the go-kart racers are doing.

The problem is that any noticeable gains are going to make it less reliable.


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## Whoopbass (Mar 18, 2011)

Try mounting a 36" lawnmower mulching blade and run it in the weeds.
The most cost effective performance gain that you can do is sell it and buy a bigger motor.


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## Jim (Mar 18, 2011)

I was looking for that link but could not find it! I still think its cool that people are actually trying to hop up the performance of these little motors. Even though the gains are tiny.


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## zseverns (Mar 19, 2011)

i really like that there r smarta$$ on here that love to give dumb answers to ?. i only asked for help not stupid answer like putting a lawnmower blade on it. thank for all the help.


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## 00 mod (Mar 19, 2011)

Some years ago, I raced Go karts! Here are the most productive and cost effective ways we added to our go karts! Granted these were fully built $750-1000 motors, and even then, they only produced around 7.5 hp!

- air breathers! The constrictive air breathers of a stock briggs 5 hp can be opened up using a "K&N type filter" 

- exhaust. The most effective was a straight pipe exhaust with a bend in it to still hold back pressure! Made the motor really load though! My suggestion would be a pipe with muffler, still load, just not as bad! 

- Amount of oil used! Most briggs require much less oil than the manufacture suggests! Although running the chances of blowing, we would reduce the amount of oil down by several ounces and also the weight! It requires much more frequent oil changes, but also produces more power via less drag!

- Changing the carb! A little more expensive mod, but can be the most helpful! Bigger carb means more fuel, which equates to more power in the long run, especially if you do the other mods!

Hope this helps, and If you have any questions feel free to ask away! 

One place you could get the air filter, exhaust, and carb would be here: 

https://www.cometkartsales.com/store/air/fabric.htm air filter

https://www.cometkartsales.com/store/p&h/briggs.htm pipe

https://www.cometkartsales.com/store/p&h/rlvbrigg.htm muffler

https://www.cometkartsales.com/store/briggs/carbdiap.htm carb

https://www.cometkartsales.com/store/briggs/images/briggsintake.jpg filter adapter for carb


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## lucescoflathead (Mar 19, 2011)

I'm a firm beliver in that everything can be souped up. You might want to try one of the lawn tractor pulling sites. They build their motors for torque. Todd


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## jixer (Mar 19, 2011)

A friend of mine races lawn mowers, I think the biggest thing they have is the ability change transmissions and sprocket sizes. He still gets new cams (Im not sure if he grinds them), Bigger carbs, lighter flywheels (he does this himself), high flow exhaust (straight pipe with a bend) ports and polishes the head (also himself) and many other things that I dont know about , basically anything that works for all 4 stroke, but he has 10 years of trial and error and I was never really into them so I cant really recomend any one thing or what the gains are.


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## Whoopbass (Mar 19, 2011)

zseverns said:


> i really like that there r smarta$$ on here that love to give dumb answers to ?. i only asked for help not stupid answer like putting a lawnmower blade on it. thank for all the help.



Sorry about the bad joke.
I would look into getting an aftermarket header pipe and a performance air filter. Autozone used to sell nitrous oxide in 2oz bottles for around $6.00. The display was nearly empty every time I went in so the stuff has to work.
Those are the easiest things you can do and you should easily see a solid 20% boost in power. If you want to go all out then your going to have to drop your outboard off at a machine shop and that could get costly.


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## sixshootertexan (Mar 19, 2011)

I know this is extreme but it's some good reading.

https://www.hotrod.com/newsletter/hrdp_0308_racing_engine_jr_drag_racing_league/index.html


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## PartsMan (Mar 21, 2011)

Does the Briggs have an air filter?

Another thing. Your motor has a rev limiter on it. You will have to disable it to get higher rpms.

For the record. I think it's a really cool idea.


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