Fuel Injection?

[briman0094]

I just got an '87 briggs 4hp lawn mower engine for free for a Small Engines class, and once I get it fixed up, I want to put it on a go kart. I know, 4hp isn't that fast of a go kart, but I am just starting to get into them. Although I like carbeurators, I would like the ease of fuel injection. Is there an easy way to add fuel injection, or if not, an automatic choke? And if so, where can I get the parts?

Thanks ahead of time!

EDIT: I forgot to add, I heard somewhere that the blade on a lawn mower acts as a flywheel, and that you can shear the flywheel key if you don't have the blade on. Is this true, and if it is, how can I get a bigger flywheel so that I can have this engine on a go kart?

 

[Kenny_McCormic]

Most mower engine of that time period came with auto choke.

Fuel injection is far more complex and expensive than a carb.

The blade does have some flywheel effect.

You can use a cast iron 4hp flywheel, it will drop in.

On top of all that, its very difficult to set up a mower engine on a kart.

 

[mike75925]

a clutch will simulate the blade's weight. you can get a mechanical injector, hook it up to a good pump. you will need to find out if the pump you are using is capable or not, bigger is better for this scenario. use a regulator to let off the excess pressure. depending on the type of injector you will have different mounting. the head will need to be drilled to accept the injector. you may be able to rig a temperature sensitive coil to the choke, when cold it will retract thus opening choke; when warm, expand and close the choke. no need for electronics. there is a whole lot i have left out, mainly because i do not know, sorry.

 

[briman0094]

Most mower engine of that time period came with auto choke.

Fuel injection is far more complex and expensive than a carb.

The blade does have some flywheel effect.

You can use a cast iron 4hp flywheel, it will drop in.

On top of all that, its very difficult to set up a mower engine on a kart.

By "difficult", what do you mean? I am going to buy a clutch and transfer case so that it can transfer the vertical shaft to the horizontal axle, and a clutch for obvious reasons. I am going to have my cousin (a hobby welder) make a custom chassis for me that will accommodate the engine and a dashboard.

 

[Linksep]

I think he means it would be cheaper AND easier to just get a horizontal shaft motor than it would be to rig up some sort of RAGB (Right Angle Gear Box). Google RAGB and you'll find the lawnmower racing guys pay $200+ for used RAGBs where you could just get a brand new Harbor Freight 6.5HP horizontal shaft motor for $72 next month (or score an old generator/snowblower/air-rake with a 5-8HP horizontal shaft for $0-$50 on craigslist).

Score yourself a $0-$72 horizontal shaft motor and use your 4HP vertical shaft for a DIY generator like this: http://www.theepicenter.com/tow082099.html

EDIT: I'm not trying to be a dick or anything, but I spent 2 months trying to figure out how/where to get a RAGB to make a trolling motor out of a 3.5HP Tecumseh... lots of time wasted and no results; not even great ideas... oh, idea RIGHT NOW!!!

The one cheap way I can think of doing this would be a friction drive similar to my 6-speed push mower.

EDIT #2
LOL... I'm 29 years old on a go kart website drawing like a 4 year old...

http://www.youtube.com/v/6B9soE8wAoI&hl=en_US&fs=1&rel=0

 

[Thedude]

A clutch will not be heavy enough to act as a blade. How are you going to make the engine power the wheels?

 

[Thedude]

Could you use a differential as a RAGB ?

 

[Doc Sprocket]

A car diff? Sure. it'd be very heavy, though. And you'd have to either weld the spider gears or permanently fix one side to keep the unused side from spinning freely.

 

[briman0094]

The lawn mower actually has an adjustable friction drive, I could make (or buy) some sort of gearbox to make it go faster and some sort of mechanical clutch to engage the drive. I like the idea of a free generator off of craigslist however, so I will look into that.