|
Post by Thomas on Aug 3, 2010 11:57:15 GMT -4
Hi guys
Recently i've taken intrest in mechanics and have started to restore an old 8hp Roper lawn tractor that a friend had lying around untouched in his barn for the past decade... This started out to be nothing but a small summer project for me to take on until i discovered lawn tractor racing! I'm looking at getting in to the stock modified class with this tractor but seeing that it's only 8hp, i probably wont be getting anywhere verry fast... What i'd like to know is what i could do to it to enhance it's speed and power as much as possible within the class restrictions.
I know the engine runs and quite smoothly for that matter, i changed the oil, battery, fuel line and cleaned the carburetor and got it started just yesterday. I still have alot of work to do on it and would appreciate it if you guys would be able to help me along the way.
Thanks!
Thomas
|
|
|
Post by Storms Racing 77 on Aug 3, 2010 20:20:58 GMT -4
Thomas, In our rules for the stock modified class you cannot have any modifications to your motor, so your very limited to what you can do to enhance your speed and power, personally i havent worked on a 8 hp motor before but it is basically the same thing as a 10 hp for how to improve it, my words of wisdom for you to help you out is this 1. Un hook the governer from your 8hp engine so that it will rev higher then stock rpm, this is a huge gain right of the start, 2. remove your flywheel from you motor, and take off the underneath charging system thats attached to your block with 4 little bolts. then put your flywheel back on, this lets your flywheel spin with less resistance since the charging system is a drag on your flyhweel since your flywheel has magnets in the inside, leave them on tho! it balances your flywheel. 3. run synthetic oil, better on the inside of your motor, and circulates better threw your motor. other then that thats all i have for you, hopefully if you do this it will help, i think it will, even tho its a 8 hp it prob revs quickly since it has a significant smaller stroke compared to a 11hp. shorter stroke quiker rpm. Steven Storms
|
|
|
Post by Thomas on Aug 3, 2010 20:32:35 GMT -4
Alright! Thanks alot Steven!
|
|
|
Post by Storms Racing 77 on Aug 3, 2010 20:32:45 GMT -4
Sorry Thomas, i just realized i went on and on about your motor only, i didnt get into gearing for you to help you out there lol umm well if you dont know what your doing with your gearing, theres lots of guys on here that can help, think about the motor stuff i just let you know and then when you want to know about gearing just drop a line right here again. Mark a spot on the edge of your transmission pulley, then mark a spot on the egde of your tire, put it in first gear and spin the transmission pulley by hand around as many times as it takes for you tire to do one(1) full rotation and keep track of how many time the pulley turns, say the pulley turns 8 times to the one of your tire, then that would mean 1st gear is 8 to 1. do this for every gear and right it all down. this will make gearing alot easier. hope this helps, i know its alot to take in but jsut read threw it and ask question whenever you want. Steven.
|
|
|
Post by Thomas on Aug 3, 2010 21:23:43 GMT -4
I'll make sure to do that!
Concerning the governor, I'm a little confused on where the thing actualy is and what's involved in taking it out?
|
|
|
Post by Thomas M on Aug 4, 2010 8:26:25 GMT -4
Ok, I found the governor and the charging system... Only problem is that from what i saw the charging system is what powers my sparkplug! Please correct me if i'm wrong. And for the governor, would it have the same effect to just unhook the arm from my carburetor? To be honest, i don't feel comfortable with myself messing around in all that, i've looked up numerous articles and instructional videos on the net and couldn't find anything with detailed or even quality instructions on a complete removal...
Thanks!
Thomas
|
|
|
Post by Storms Racing 77 on Aug 4, 2010 17:42:29 GMT -4
Is your 8 hp briggs and stratton engine? if so the system your talking about that goes to your spark plug would be your coil, it creates a charge from the side of your flyhweel to create spark. your charging system wouild be underneath the inside of your flywheel on your block, its circular, and has little circle metal charging pads along the side of it wrapped with copper colored wire. its hard to miss when you take the flywheel off, cuz its the only thing there that breaks up the view of just the block of your motor. it should have two wires coming off of it into a plug in tip. and for your governer, since you've found it you've seen how the arm goes into the side of your motor and it will move back and forth a little bit, well if you unhook that arm from your carb and tie it back all the way that it can that will be holding your governer open, that saves you from removing it. its hard to explain over a chat without pcitures or anything but i hope that helps you, and remeber when dealing with your carb, to tie the choke butter open on the arm that controls it, you dont want you motor choked, it wont run, and if you take you charging system off, yes it helps your motor, but you will have to regularly charge your battery after that since the motor wont be doing that for you. Steven.
|
|
|
Post by Storms Racing 77 on Aug 4, 2010 17:43:40 GMT -4
sorry ment to say choke butterfly, my bad with the typo
|
|
|
Post by Thomas M on Aug 4, 2010 17:48:43 GMT -4
Aweeeesome! Thanks alot Steven for your help! But about the choke , wouldn't i need it to get the engine started?
|
|
|
Post by Storms Racing 77 on Aug 4, 2010 18:04:04 GMT -4
No problem thomas, this is what the message board is for, and nope, if your racing with us you'll be racing during the summer and shouldnt need a choke to start it, i run four machines and all have the choke wired open, and i start them all no problem.
|
|
|
Post by Thomas M on Aug 5, 2010 14:23:27 GMT -4
Well everything just took a huge turn on me... My tractor wont start anymore! I just got my tires back from the shop after having them replaced and i was going to take it for a quick spin to check to see if the gears still work. I turn the key, it starts, lets out a few puffs of black smoke, then dies on me. I try to start it again and nothing happens but more black smoke puffs out but this time through the carb! The timing seemed off a little off too?! I gave it one last try, it didn't fire at all but the puffs of smoke from the carburetor stopped... I've done nothing to the engine itself for it to do this. One of the problems may be that with all the rain we've gotten and the humidity today it just screwed something up?
|
|
2 Kool
Junior Member
Posts: 90
|
Post by 2 Kool on Aug 5, 2010 16:48:40 GMT -4
Check the key on the fly wheel and check the magnet on the flywheel is sanded clean and the coil John
|
|
|
Post by Storms Racing 77 on Aug 5, 2010 18:23:42 GMT -4
Thomas, have you done anything to the motor that i suggested? if so or even if not, check your flywheel clearance from your flywheel to your coil, take a fine grit piece of sandpaper and put it between the flywheel and coil, this will be your space you should have for a good charge, make sure that its even tho, and not touching your flywheel, im not sure the thous that you should have but dont go under .005 thous for clearance, thats to close, also check your keyway on your flywheel, it is probably where it should be and isnt the problem, im not a genius on these motors, not even close, LOL but it almost would seem like your having valve problems... it seems like your exhaust valve is off timing with your intake valve to have smoke coming up threw your carb... but thats just a theory, have you ever started the engine before? does it have oil in the motor? not to seem like im asking stupid question but ive had one of my engines run out of oil and have smoke come out the exhaust like you wouldnt believe, so every question is necessary just incase lol. but that all i got for you on this, hopefully someone else will jump in to help me on this, but if not i'll keep trying to give you any advice i can. Steven.
|
|
|
Post by Thomas M on Aug 5, 2010 19:00:15 GMT -4
Sorry but i havn't done any of what you've suggested yet, i've been pretty busy over the past couple of days so realy i didn't have the time. I certainly will after i get this problem solved.
I had the engine running a couple of times a few days ago but other than that it's just been sitting on jacks since i had the wheels in for replacement... It's got fresh oil in it. Now just wondering lol, what exactly is the keyway?? And say it is a valve problem, what would be involved in fixing that?
I'll check the clearance between the flywheel and coil and let you know how things turn out.
Thanks!
|
|
|
Post by Thomas M on Aug 5, 2010 19:34:57 GMT -4
Ok so i've got the brushes at diferent distances from the flywheel. One is at .006" and the other .004".
|
|