ptracy70 2 #1 Posted May 14, 2019 ok,i was just given a c-81 and the motor needs rebuilt, so i thought to buy a used motor, but dont know what will fit and what to do now. 1 Share this post Link to post Share on other sites
formariz 11,849 #2 Posted May 14, 2019 Welcome aboard. I am not too familiar with that model but no worries, many will chime in shortly. Share this post Link to post Share on other sites
Ed Kennell 35,146 #3 Posted May 14, 2019 the Phil. The C-81 has the 8HP kohler engine with the rocker plate mount. If you are considering replacing the engine with a different make or model engine, adjustments to the mounting plate may be necessary to get the centerline of the crankshaft at the same elevation. This is necessary for the belt guard and belt clutch to operate properly. There are many posts detailing the steps involved in rebuilding a Kohler if you decide to go that route. If you are looking for a used replacement, you could post an ad in our classified wanted section. There are many experts on here willing to answer your questions and offer advice. Garry will probably check in soon and supply a link to the manuals for your tractor. Keep us posted. Share this post Link to post Share on other sites
Stormin 9,975 #4 Posted May 14, 2019 If you've any mechanical ability, I'd rebuild. They're simple engines to work on and doing so you would end up with an engine you would know is ok. A used engine is of unknown quantity, no matter what the seller may tell you. 1 Share this post Link to post Share on other sites
ebinmaine 62,360 #5 Posted May 14, 2019 Welcome to Redsquare Phil. You have an advantage in CT of a good amount of our own members being available for help or parts sales. Ask all the questions you can. This site will get you fixed right up. @gwest_ca is the manual man. Share this post Link to post Share on other sites
Pullstart 58,794 #6 Posted May 14, 2019 First of all, to and ! I had good luck finding a gas powered air compressor that had a leaky tank for an engine swap on my 502 “Putt Putt.” I bought it blindly and took the seller’s word for the way it ran, because that wasn’t the reason it was cheap... Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,444 #7 Posted May 14, 2019 The C-81 was made in 1978 and 1979. This link will take you to 43 files on 2 pages so look through them all. They are in no particular order. https://www.wheelhorseforum.com/search/?&q="c-81"&type=downloads_file&search_and_or=or Let us know if there is something you can not find. The 8hp engine is a Kohler model K181 (K-Series design, Approximately 18 cubic inches, 1 cylinder) Engine service manual Garry Share this post Link to post Share on other sites
ebinmaine 62,360 #8 Posted May 14, 2019 7 hours ago, phil t said: ok,i was just given a c-81 and the motor needs rebuilt, so i thought to buy a used motor, but dont know what will fit and what to do now. It just occurred to me to ask why you think the motor needs to be rebuilt? Has it been professionally diagnosed or did somebody decide that simply because it doesn't start or won't quite run right? Quite a good many of us have tripped over perfectly good machines that a previous owner just didn't want to deal with. Share this post Link to post Share on other sites
Pullstart 58,794 #9 Posted May 14, 2019 8 minutes ago, gwest_ca said: The 8hp engine is a Kohler model K181 (K-Series design, Approximately 18 cubic inches, 1 cylinder) Engine service manual Never considered the engine size / model breakdown... thanks Garry! Share this post Link to post Share on other sites
Achto 26,199 #11 Posted May 14, 2019 (edited) Engine swaps can be challenging to do, not saying that it's wrong. There is usually a hurdle or two to get through. The old K model Kohlers are relatively easy to rebuild and last a long time, if you should decide to go that route. Either way keep us posted on your decision and progress. Edited May 14, 2019 by Achto Share this post Link to post Share on other sites
953 nut 51,018 #12 Posted May 14, 2019 Is the engine in question in running order and needing some attention, if so I'm with the rebuild it group. A good used engine if it has been properly maintained will probably last several years. A correctly rebuilt Kohler engine with proper maintenance will probably outlast you. The price differential may seem significant, but over the years of ownership it will be beneficial to you to rebuild the engine. 2 Share this post Link to post Share on other sites
bottjernat1 2,189 #13 Posted May 14, 2019 Welcome! To this forum it is full of great folks!! I would rebuild it over finding another what might be lemon. You will be much happier! The kohler 8hp is a great engine! and stens and other companies sell rebuild kits fairly cheap for it. but if you want find a cheapy motor for the mean time and start taring yours apart. You cant beat the old 8hp kohler. I have a few machines wheelhorses and deeres with that motor. Share this post Link to post Share on other sites
12 hp Kohler 1,014 #14 Posted May 14, 2019 (edited) I would definitely consider rebuilding the 8hp kohler. They are great little engines with lots of power. My c-81 is my go to tractor for everything and it always gets the job done. Edited May 14, 2019 by 12 hp Kohler Share this post Link to post Share on other sites
oliver2-44 8,770 #15 Posted May 14, 2019 3 hours ago, ebinmaine said: It just occurred to me to ask why you think the motor needs to be rebuilt? As EB asked, tell us more about the motor. We can help determine if truly needs an overhaul, or some minor attention ...carb cleaning, valves adjusted, etc Share this post Link to post Share on other sites
clueless 2,893 #16 Posted May 14, 2019 If you don't want to rebuild it then the best option is to find a kohler K series 8, 7 or 6.25 hp engine. Your tractor has the shaker mount, if you go with the larger kohler engines (big blocks) you will need the ones with the shallow oil pan to fit the cradle.Even if you find a big block with the right oil pan your still going to have to do some some adjusting, belt guard, throttle cable, pto size, and maybe some wiring . If you put some other brand engine on it same thing. The small block Kohler K series engines except the 4 hp is pretty much a take the old one off and bolt the new one on, hook everything back together and off you go . Share this post Link to post Share on other sites
adsm08 1,429 #17 Posted May 14, 2019 10 hours ago, ebinmaine said: It just occurred to me to ask why you think the motor needs to be rebuilt? Has it been professionally diagnosed or did somebody decide that simply because it doesn't start or won't quite run right? Quite a good many of us have tripped over perfectly good machines that a previous owner just didn't want to deal with. ^THIS^ I bought one a few weeks ago that wouldn't run due to "electrical problems". The battery was 10 years old and FUBAR. That was the extent of the "electrical problems" keeping it from running. The 10 year old fuel was why it didn't run. 1 Share this post Link to post Share on other sites
ptracy70 2 #18 Posted May 17, 2019 thanks guys. the neighbor,taught his daughters to mow the grass but not to check the oil.the block is ok, broke the rod at the crank. i might try to sand down crank and keep measuring it.any solutions or what to do would be helpful.just trying to keep tractor from scrap metal pile.when i get a chance ill post a picture. Share this post Link to post Share on other sites
ptracy70 2 #19 Posted May 17, 2019 also what is the best rebuild kit for this motor Share this post Link to post Share on other sites
Achto 26,199 #20 Posted May 17, 2019 14 minutes ago, phil t said: also what is the best rebuild kit for this motor Here is one source. http://www.psep.biz/store/kohler_rebuild_kits.htm Advice on the crank would be to take measurements. It may need to go to a machine shop to be turned down. If so have them inspect it and let you know which under sized rod you will require. 1 Share this post Link to post Share on other sites