Is it even possible to run a 4.5 horsepower gas lawnmower engine to power a go cart . I'm using aluminum alloy framework and keeping the weight to a maximum of 200 lbs. Plus the driver for total weight of 400 lbs. Would a Briggs and Stratton 4.5 HP be worth the effort. Speed and torque ??? Ideas and past experiences please. Thanks Yea. I'm obviously a Rookie 2
Bear with me folks. Not well informed on engine requirements for a new go kart build. I'm only in the drawing and design stages. I've got a small budg
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Bansil
Painter of gnomes....
200# is alot, especially using aluminum...... 
Build the kart , leave room for a bigger engine and have fun....99% of drive train will be the same.
Its more about gearing and smiles......
Build the kart , leave room for a bigger engine and have fun....99% of drive train will be the same.
Its more about gearing and smiles......
EpsilonZero
...still cheaper than a boat!
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Do you have experience welding aluminum?
OPmini
moo
Try the predator 420 big block with a 40 series CVT, tons of power out of the box. Also, why are you choosing aluminum? and do you have experience TIG welding?
Denny
Canned Monster
You got my vote for best and longest title. If you mean vertical shaft engine then no. Horizontal shaft engine then yes.
soilsamplerbill
New member
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When I was about 12 years old, my uncle gave me his old racing kart frame. When he raced it, he used (2) West Bend 910 2 stroke engines (18 hp). My grandfather gave me an old Briggs & Stratton 9/10 hp (yes, nine tenths of a hp) horizontal shaft engine. Had no way to know the speed, but it was faster running with the wind and would slow down in a head wind. Later, I bought a 5 hp engine that a neighbor had taken off a reel mower. It was in boxes in parts. I reassembled it and the kart would run about 30-35 mph. So your 4.5 would work. If you have a vertical shaft engine, you will probably want a jack shaft driven by a V-belt that you can twist 90 degrees to get your horizontal drive. It would probably save money in the long run to go to Harbor Freight and get a 6hp Predator Horizontal Engine. If you don't mind spending the money, a torque convertor would help the kart accelerate or a double centrifugal clutch/ jackshaft arrangement can do the same thing. Its kind of like having a two speed.
As far as your choice of material, there are a lot of different aluminum alloys and unless you have a lot of experience, welding it well is not that easy. I expect you will spend a lot of time repairing the frame. Aluminum does not like repeated flexing and will break. Steel will flex and give you some suspension along with the tires. I would use maybe 1-1/4" 14ga. 4130 chrome moly tubing for the main frame members and maybe 3/4" - 1" 18ga. for support members. Very light and strong. Gusset your joints if they see stress and your frame will last. You will also need all sorts of steel parts for the steering and it's easier to be able to weld them to the steel frame. You can use aluminum for the floor and rivet or screw to the bottom of the frame. Lot's of frames are built with square mild steel tubing and makes things very easy to fit up. Someone else on this forum can probably speak to sizes and thickness.
However you decide to go, plan it out with sketches or drawings, and have fun building and driving it!
As far as your choice of material, there are a lot of different aluminum alloys and unless you have a lot of experience, welding it well is not that easy. I expect you will spend a lot of time repairing the frame. Aluminum does not like repeated flexing and will break. Steel will flex and give you some suspension along with the tires. I would use maybe 1-1/4" 14ga. 4130 chrome moly tubing for the main frame members and maybe 3/4" - 1" 18ga. for support members. Very light and strong. Gusset your joints if they see stress and your frame will last. You will also need all sorts of steel parts for the steering and it's easier to be able to weld them to the steel frame. You can use aluminum for the floor and rivet or screw to the bottom of the frame. Lot's of frames are built with square mild steel tubing and makes things very easy to fit up. Someone else on this forum can probably speak to sizes and thickness.
However you decide to go, plan it out with sketches or drawings, and have fun building and driving it!
madprofessor
"Loose Cannon Creations"
The square steel tubing is definitely the way to go on your budget, just don't overbuild it like I did. 1.5" square 11 gauge steel tubing is ridiculous, Samsonite gorilla strong. Everybody uses 1" square steel tubing, about 1/8" thickness.
Use an angle grinder with metal cutoff wheels to cut all your steel. A 120 volt plug-in inverter stick welder can weld it all up cheap.
Sit on the garage floor with a Sharpie marker. Draw your knees up like in a comfortable gokart, mark the floor around you as the frame of the kart, leave room for the engine. Measure it to estimate your steel purchase, and get twice that much.
Use an angle grinder with metal cutoff wheels to cut all your steel. A 120 volt plug-in inverter stick welder can weld it all up cheap.
Sit on the garage floor with a Sharpie marker. Draw your knees up like in a comfortable gokart, mark the floor around you as the frame of the kart, leave room for the engine. Measure it to estimate your steel purchase, and get twice that much.
65ShelbyClone
Active member
A vertical shaft engine? Possible, yes. Practical, not so much.
Racing karts are made of steel and weigh vastly less than that. The bad news is that aluminum will be a very poor choice of material. It requires advanced welding knowledge and skill and something most people don't consider: post-weld heat treatment of the whole frame. The only common vehicles I know of that use aluminum frames are bicycles and motorcycles. They are a special case because twisting loads across the frame and deflection are much lower than in a four-wheeler, but the frames are still heat treated after welding.
Bansil
Painter of gnomes....
I must disagree to a point, they are actually annealed and then drawn to whatever temper the engineer specs, 7075 is a great alloy for twisting and flex, it will bend (to a point) and go back to natural form.
6061 in any HT. Will Crack, 5052 and 2024 have great bend in twist properties just not the strength as 7075.
We always used it for lower 4 link arms on trucks/buggies because when you landed on a rock and link bent, it would recover almost perfect and spring you off the rock and still be straight and lighter than steel.
Now on that note, if engineered right (or close) it would be alot lighter, problem is 2+× the price of steel
BUT...if....you...are comfy with the traits of aluminum and can weld it........
Yeah...kick butt take names and post pictures.
With skill and knowledge, a carbon fiber and aluminum frame would weigh maybe 1/4of a normal frame, but ....alas, those folks work for spaceX of Tesla
And it would be stupid..$$$$...
65...This is not a dice/rant etc...just more info for OP ,to make decisions
6061 in any HT. Will Crack, 5052 and 2024 have great bend in twist properties just not the strength as 7075.
We always used it for lower 4 link arms on trucks/buggies because when you landed on a rock and link bent, it would recover almost perfect and spring you off the rock and still be straight and lighter than steel.
Now on that note, if engineered right (or close) it would be alot lighter, problem is 2+× the price of steel
BUT
...if....you...are comfy with the traits of aluminum and can weld it........Yeah...kick butt take names and post pictures.
With skill and knowledge, a carbon fiber and aluminum frame would weigh maybe 1/4of a normal frame, but ....alas, those folks work for spaceX of Tesla
And it would be stupid..$$$$...
65...This is not a dice/rant etc...just more info for OP ,to make decisions
madprofessor
"Loose Cannon Creations"
Just curious, Rookie 2: Are you using aluminum tube because you want to be a race kart driver with all the advantages, or because you happen to have that stuff already? With a Briggs 4.5hp. vertical shaft motor in the planning I'm guessing you already have that too, and it's the latter of the two options because it's budget-driven all the way.
If that's the case, don't clog your brain with the intricacies of "exotic" metals and other messes of mass. Steel tubes and a 120volt plug-in arc welder are your cheapest route frame-wise. The advice of getting a Harbor Freight Predator 6.5hp. engine would end up being your cheapest route also, not to mention easiest.
If that's the case, don't clog your brain with the intricacies of "exotic" metals and other messes of mass. Steel tubes and a 120volt plug-in arc welder are your cheapest route frame-wise. The advice of getting a Harbor Freight Predator 6.5hp. engine would end up being your cheapest route also, not to mention easiest.
Denny
Canned Monster
Club Car golf carts use an aluminum frame, and have for many years.
65ShelbyClone
Active member
Because golf carts are highly stressed structures....
I don't intend to sound rude, but I'm not sure what the argument is. 7075 isn't considered to be weldable by standard processes and carbon composites are well out of the scope of this thread.
I must disagree to a point, they are actually annealed and then drawn to whatever temper the engineer specs, 7075 is a great alloy for twisting and flex, it will bend (to a point) and go back to natural form.
6061 in any HT. Will Crack, 5052 and 2024 have great bend in twist properties just not the strength as 7075.
We always used it for lower 4 link arms on trucks/buggies because when you landed on a rock and link bent, it would recover almost perfect and spring you off the rock and still be straight and lighter than steel.
Now on that note, if engineered right (or close) it would be alot lighter, problem is 2+× the price of steel
BUT
Yeah...kick butt take names and post pictures.
With skill and knowledge, a carbon fiber and aluminum frame would weigh maybe 1/4of a normal frame, but ....alas, those folks work for spaceX of Tesla
And it would be stupid..$$$$...
65...This is not a dice/rant etc...just more info for OP ,to make decisions
I don't intend to sound rude, but I'm not sure what the argument is. 7075 isn't considered to be weldable by standard processes and carbon composites are well out of the scope of this thread.
Bansil
Painter of gnomes....
Not being rude, you are correct about weldabilty of it, we never had to weld it to make 4 links.
Also the carbon fiber remark was purely to show that steel isn't best. For Karts it's perfect, cheaper, easier to fabricate with common tools and welders.
The post was merely to think outside the
Sorry op for thread direction
Also the carbon fiber remark was purely to show that steel isn't best. For Karts it's perfect, cheaper, easier to fabricate with common tools and welders.
The post was merely to think outside the
Sorry op for thread direction