alternative fuel go cart...

[Pipeless416]

alright, so some classes at my school are working on making a 5 hp tecumsah powered go cart run on ethanol. right now its running at about a quarter mix of ethanol and regular gas. somebody is saying that there is an extra oxygen atom in ethanol, causing it to lean out the mixture. the problem is that they want to run a higher mix of ethanol, but the carb on the tecumsah engine is not very adjustable. would we be best off trying to find a carb with actual jets? also, the biggest concern of the students is trying to make the thing faster... is there anything that could be done? i'm trying to get them to scrap the stock lawn mower air filter setup and replace it with a machined bracket that a k&n will bolt up to to start. all of the guys that asked me to help know plenty about fabrication, but they dont know beans about modding engines. :) any suggestions are appreciated.

[CDCHONDAS]

ok your doing 2 things to lean out the mixture, the ethanol and they k&n. so this leans the engine 2 ways, the k&n would be free-er flowing likely so that will create less suction on the carb, therefore less fuel will get sucked through the jets, as for the fuel I really don't know alot about ethanol but it sounds alot like alcohol from what I know, alcohol burns lean like your ethanol, and really takes somewhere around twice the amount of fuel to power the engine, once again I do not know the ethanol. So I think I would buy a few new stock jets, get a set of jet drills that can drill to the thou. and start playing, make note of how big a hole you have cut so that when you get too rich you can bore the next size or two smaller in one of your new jet. i say drills because i doubt your going to get factory jets like that. You will have to richen it up quite a bit. Other thing you could do is get a cheap very small mikuni carb, adapt on it let er rip, with something like the mikuni you can get hex jets very very big and inexpensive. sounds like a fun project.

[Pipeless416]

i was hoping for a response like that because before we go investing in a carb that we can actually adjust the right way, we were just going to drill the fuel "jet" a little bit bigger each time. i'll be measuring the intake port tomorrow to see how big of a carb we would need. thanks for the help! a fully adjustable carb would be very nice right now..

[Slinky]

Originally posted by Pipeless416
i was hoping for a response like that because before we go investing in a carb that we can actually adjust the right way, we were just going to drill the fuel "jet" a little bit bigger each time. i'll be measuring the intake port tomorrow to see how big of a carb we would need. thanks for the help! a fully adjustable carb would be very nice right now..
search for the guys that race these carts.....they run them on alcohol. they will probably have some pointers on where to get either parts of the carb or a more adjustable carb that will bolt on.