Karts of Kaos
the many mowers guy
I would like to get a mccooney style carb for my 5 hp briggs what size should i get. thanks!
5hp briggs carb
- Thread starter Karts of Kaos
- Start date
Brianator
Gettin' er done!
*Mikuni* so you know. How many cc's is the engine? I'll take a guess and say a VM19 (19mm) (round slide) would be good and last I checked seller Raceguy on Amazon still had genuine Mikuni ones that even have a cable (and hand) operated choke. Keep in mind you'll probably have to make your adapter manifold. I have the exact one and it's a great carb, the fuel/adjustment is an "air screw" so keep that in mind also. You might have to fab up your own throttle cable also by using a pocket bike cable as a start.
Karts of Kaos
the many mowers guy
it is 206cc. guessing early 2000's.
Mr_mcrib212
Inmate #2148
A Briggs 5hp would be about 204cc so a 22mm or 24mm Mikuni would work well, you might have to buy some kind of bracket or make your own.
Brianator
Gettin' er done!
Quick question, what's the original carbs outlet diameter and what kind of rpms are you turning? Bigger isnt always better....
Karts of Kaos
the many mowers guy
I am not going for performance I have had a lot of trouble with this style of carb before and I wanted to try a different one.
Brianator
Gettin' er done!
In that case a carb that is the same size (outlet diameter) or a hair bigger is your best bet, too big and you kill velocity down low (which hurts torque). I made a mistake on the carb model also, the VM16 is 19mm.
JTSpeedDemon
2019 Build Off Winner!
Brianator - 5 HP intake ports are 22mm, so @Kaos, you need a Mikuni 22mm round slide carburetor.
A 19mm or a 20mm would work, but it wouldn't be much better than the stock carb, it would still be a restriction. The carb outlets on Briggs come from the factory smaller than the intake port, restricting it.
Kaos- You are working on a flathead, right???
A 19mm or a 20mm would work, but it wouldn't be much better than the stock carb, it would still be a restriction. The carb outlets on Briggs come from the factory smaller than the intake port, restricting it.
Kaos- You are working on a flathead, right???
Brianator
Gettin' er done!
I DID recommend a carb the same size as the original or just a hair bigger based on his needs. I mentioned the 19mm earlier not realizing a 5hp briggs has that large of a intake port. Interesting that a manufacturer would want to slow the air down just before the valve... makes me think maybe the 5 and 7/8hp are built on the same platform with a few minor differences. You can gain basically 1hp on those with a bigger carb right? That's about halfway there.... lol. You know what the power difference is between a 90's Corvette and Camaro (with the same engine)? Not much, the Camaro was only detuned because it cant be as fast as GMs flagship sports car....
JTSpeedDemon
2019 Build Off Winner!
Yup, I'm just inputting the correct measurements, you still gave good advice! 
IIRC the >5 HP flatheads are built on an entirely different platform from the 5 HPs, sharing almost no components. To us it's odd they would restrict it, but ya also gotta remember, these engines were designed for rototillers and such, so they needed to be fuel sippers to sell to people.
I think a carb upgrade can easily yield 1 more HP, but I think if the stock carb throats were opened up, it wouldn't be as much. It really depends on which carb is used to replace the factory one.
IIRC the >5 HP flatheads are built on an entirely different platform from the 5 HPs, sharing almost no components. To us it's odd they would restrict it, but ya also gotta remember, these engines were designed for rototillers and such, so they needed to be fuel sippers to sell to people.
I think a carb upgrade can easily yield 1 more HP, but I think if the stock carb throats were opened up, it wouldn't be as much. It really depends on which carb is used to replace the factory one.
mckutzy
Well-known member
I surprised no one has said go Bronda.....Get a clone carb and make an adapter to fit you motor...
JTSpeedDemon
2019 Build Off Winner!
^^True, they are dirt cheap at like 5-10 dollars per carb.
But IMO, if he's upgrading the carb anyways, might as well go Mikuni.
But IMO, if he's upgrading the carb anyways, might as well go Mikuni.
Budget GoKart
Aka a kenbar
Mckutzy i was building a bronda but it ended up having no spark or compression so i gave up and lost the intake but im building a new one and im putting a chinese vm22 on a 2hp briggs flathead i hope i can atleast i dont have a tool to mesure the intake
Edit: the engine is at my grandpas at the moment so i cant even if i had the tool lol
Edit: the engine is at my grandpas at the moment so i cant even if i had the tool lol
JTSpeedDemon
2019 Build Off Winner!
The 2 HP'll probably have the same 22mm intake port, 'cause the carbs are interchangeable between a 5 HP and a 3 HP, so 2 HP probably has the same.
Brianator
Gettin' er done!
And I do appreciate that! In all honesty I don't know much about the Briggs flatheads yet but I did bring one back to life that was left to die 20 years ago and I love it!
Karts of Kaos
the many mowers guy
yes. i was planing on mikuni clone.
Budget GoKart
Aka a kenbar
I got a cheapo 20mm carb so i hope it works also i have a welder to build stuff with
Brianator
Gettin' er done!
Nice! Keep us posted eh!