Bobyboy101 Posted December 6, 2006 Posted December 6, 2006 yep there are many uses for lawnmower engines inclding home made go carts/dune buggies. Share this post Link to post Share on other sites More sharing options...
n_w95482 Posted December 6, 2006 Posted December 6, 2006 I had a go-kart with a 3 HP Briggs and Stratton rototiller engine, and it actually did pretty well. It kind of accelerated like an electric car, slowly but smoothly (centrifugal clutch ). The fastest I've gone in it would probably be between 20 and 25 MPH, but based on how low it was revving (it doesn't begin rising off of idle RPM until about 15 MPH), I'm sure it could have done closer to 40 if it had enough room. Seeing how I had been riding it since I was 4, it became too small for me and my dad sold it earlier this year without telling me . Share this post Link to post Share on other sites More sharing options...
dr_bowtie Posted December 6, 2006 Posted December 6, 2006 carts are fun... most of the time check around... you can find Yard cart frames anywhere... or buy a cart...heck wal-mart can get them for $700.00 and thats pretty cheap for a complete cart... then all you do is mod it... Alot of the newer ones have a pretty good suspension on them and that would make riding more fun and less hurtfull on the body... I always ached for days after hard riding... I remember one time ramping may cart too much and broke it completely in half landing from a jump... I hurt more from laughing than anything... Carting is mostly about learning...alot of trial and error goes into making it all work right... I had to make alot of my own stuff or mod stuff to the cart... I went from the stock type #35 chain to #45 heavier chain and clutch because I kept busting the smaller chain... I played alot with clutches as far as lock up rpm... most of them wouldnt hit til about 4000rpm... to get the higher mph you have to wind the engine higher...which means you have to defeat the govenor... It is there so it doesnt wind past a given rpm for the purpose it was made for...alot of carts run over 10,000rpm but it takes the right parts to do that.... I think I hit around that on the Tech5hp I had and scattered it twice... The best to use are Brigg's or Honda's...you can find Brigg's stuff anywhere...look at jegs.com for their jr-dragsters... best thing to do is if wanting to play with carts and small engines... learn how to rebuild them... that way you understand how to get more power out of them... I got to a point where I needed more compression...(more compression = more power...more power = faster) so I started milling the head by sand paper.... then I got to where I didnt use a head gasket and just used "Ultra copper" spray adhesive.... that worked ok... so then I used notebook paper and ultra copper and that worked better... I gain quite a bit but that didnt last long... Easiest thing would to use a higher compression piston... but I was doing this on a teenagers budget.. next I messed with the cam shaft phasing...(advancing the cam means more off the line pull...retarding means more top end speed)... then I got to where I mixed my own gas for higher octane.... paint store supplies added to gas make the octane higher...(google) or just buy racing gas....104 octane is good enough... In the end I prefered the Honda because it had CD ignition (capasitive discharge) and it would burn more fuel... then learn to set the carb up right... I always used a 8hp brigg's carb and matted it to what ever engine I ran and then set the high idle jet accordingly...you have to set this with the engine running it's max rpm+load+1/8 turn more out... I have been wanting to build a full out shifter cart but haven done it... they make full size carts here that are in between yard cart and dune-buggy size... they have a full suspension and good travel... I have a Yamaha 750 FZR engine I have been wanting to matt to the frame.. would be a blast to drive... Share this post Link to post Share on other sites More sharing options...
zkissane Posted December 6, 2006 Posted December 6, 2006 How did you get one to go 88mph? They put a flux capacitor on it and always thought 4th dimensionally. Duh! Share this post Link to post Share on other sites More sharing options...
dr_bowtie Posted December 6, 2006 Posted December 6, 2006 80mph is pretty easy once you defeat the govenor...(remove it) normal side pull engines run anywhere from 4500-5500 rpm we were winding ours around 8200 and the straights... Share this post Link to post Share on other sites More sharing options...
WintersFury Posted December 6, 2006 Posted December 6, 2006 Mmmmmm... GO-Karts... Theres 3 engines for Ultralights up in my Uncle's attic... I should see if I can use em to make a Super-Kart... But I'd be afraid of how fast it would go with just one of em... Let alone 3... Share this post Link to post Share on other sites More sharing options...
mihkail Posted December 7, 2006 Posted December 7, 2006 i loosened the governor screw on mine, not all the way though, i was afraid i would throw the rod. I dont know if its hitting the rev limit again or if its reaching max power, because if i leave my foot on the gas all the way, i can feel the power drop out and it kind of stalls for a second and backfires before it revs back up. i think its getting somewhere around 4000-5000 rpm, im not really sure. i need to know the rev limit on my engine and what rpm im getting for sure though. so i dont really want to take out the governor screw any more because i dont really want to rebuild it, but it might be fun to do over christmas break. except im trying to save money for my car im getting in the spring... the higher compression sounds like a good idea, i always wanted to put a small turbo on it, but i figured it would be kind of useless without a tranny. ive thought of fabbing my own air intake... when you talk about tuning the carb you mean the mixture right? or are you talking about the jet? i forgot, one thing i could do is make the mixture a little more lean, its at about max rich right now, explains all the back firing... Share this post Link to post Share on other sites More sharing options...
dr_bowtie Posted December 7, 2006 Posted December 7, 2006 Hey.... I wrote a 5000 word post and then the kid hit the power button on me...so it's gone... But the condition you list is a lean condition known as lean surge...you need more fuel... what kind of carb set up do you have... the carb bolted to tank like mowers or a side-draft carb....? Side drafts are easier to deal with...if you dont have one find one... and an adapter... make sure the screen in the tank is clean and so is the carb on the inside... Dont worry about rev limits... the engine will stop reving before it hurts itself provided the internal tolerances are tight... it will get to a point it will stop pulling because the cam cant keep up...you'll be way past peak power so the engine wont destruct as easy as it would as if you were hitting peak at higher rpm... make sure you have good spark...you should have a fat dark blue spark that really pops (snaps) yellow or red spark is no good...too weak at higher rpm... Share this post Link to post Share on other sites More sharing options...
mihkail Posted December 7, 2006 Posted December 7, 2006 i have a side-draft carb. you say that my mixture is too lean and thats why the power is dropping and its stalling? so i need to get a bigger fuel jet? i thought it was because it was going past peak power and then the governor stoped it from going higher, because i didnt really take the governor completely off. ill check the spark plug too. my friend says if i get a hot spark plug it will get more power Share this post Link to post Share on other sites More sharing options...
Guest YuKoN Posted December 7, 2006 Posted December 7, 2006 You can start a motor w/o a blade or pulley in the case of a rider but it will much more difficult. The blade helps to keep the engine turning believe it or not. he's right. although it's possible to start one- you can't get much power out of smaller lawnmower engines without the blade(or some sort of flywheel). It's true that they're balanced seperately, or you couldn't change the blade without re-balancing the assembly. The problem isn't necessarily running it once it's fired up- but even with a good yank on the starting cord, without the extra momentum of the blade swinging around they're a classy lady to start, and have next to no low end torque. on a side note- i used to have a go cart with two stihl 090 engines on it- and i was clocked on the freeway doing 90+mph- that's what my parents heard on the police scanner lol but they never caught me.......... Share this post Link to post Share on other sites More sharing options...
dr_bowtie Posted December 7, 2006 Posted December 7, 2006 i have a side-draft carb. you say that my mixture is too lean and thats why the power is dropping and its stalling? so i need to get a bigger fuel jet? i thought it was because it was going past peak power and then the governor stoped it from going higher, because i didnt really take the governor completely off. ill check the spark plug too. my friend says if i get a hot spark plug it will get more power Ok I got a minute so I'll help you out... Make sure the bottom of the gas tank is higher than the carb itself... this will insure sufficient gravity for the fuel...as stated make sure the screen is clean in the tank...the fuel isnt pressurized and relies on gravity to feed the carb...any little restriction reduces fuel flow.... now for the carb... set the rear of the cart on jack stands as you'll be running this at full throttle to set the main jet... now look at the carb... you should be able to find 2 set screws.... one on top of the carb and one on the bottom that goes thru the nut that holds the fuel bowl on.... the top screw is the idle screw... you can set this by turning the screw in clockwise just until the engine starts to die.... turn it slow... now back it out about 1 full turn counterclockwise (you can adjust between a 1/2 and a full turn for best off idle performance) now the bottom screw.... for this you will need to run the engine at full throttle or close to it to set properly... becareful doing this... dont get around the tires... with the engine at full throttle screw in the bottom screw just until you can hear the rpm start to drop a tiny bit... then back out the screw just until the engine revs back to where it was... once it revs no higher back it out another 1/2 turn.... you can test by driving to see how it goes... try backing it out another 1/2 ( for 1 full turn) and retest.... set it where it gives you the best performance.... Now for the spark.... a hotter spark wont make it faster...but a hotter spark will allow you to burn more fuel which will make it faster.... Start with that.... Share this post Link to post Share on other sites More sharing options...
mihkail Posted December 7, 2006 Posted December 7, 2006 just got my sprocket in today, i installed it but i have to wait until tomorrow to put the chain on. my garage door broke too so i dont know how im going to get it out.... Share this post Link to post Share on other sites More sharing options...
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