Coadster32 793 #26 Posted July 25, 2009 If you want premium gas try two Toco Bell Burrito Supremes and a six pack of Bud Now that's funny right there!! :thumbs2: Share this post Link to post Share on other sites
bitten 133 #28 Posted July 25, 2009 The Kohler single cylinder service manual says: "For best results, use only clean, fresh, unleaded gasolin with a pump sticker octane rating of 87 or higher. In countries using the research method, it should be 90 octain minimum. Unleaded gasolin is recommended, as it leaves less combustion chamber deposits. Leaded gasolin may be used in areas where unleaded is not available and exhaust emissions are not regulated. Be aware however, that the cylinder head will require more frequent service. Gasohol(up to 10% ethyl alcohol, 90%unleaded gasolin by valume) is approved as a fuel for Kohler engines. Other gasolin/alcohol blends are not approved. Methyl Tertiary Butyl (MTBE) and unleaded gasolin blends(up to a maximum of 15% MTBE by valume) are approv3ed as a fuel for Kohler engines. Other gasolin/ether blends are not approved." This is out of the K series manual. All I have in Wheel Horses is the K series, and use 92 from Sunoco. They all run great. I have not tryed lower octain fuel, and other then money have no reson to. I hope this helps. Share this post Link to post Share on other sites
porkchop 1 #29 Posted July 25, 2009 Automobile engines from about 1975 and newer have hardened valve seats. There is no reason to run a lead additive. I assume the kohlers do too starting around 1975. Any engine older then this probably doe,s not have hardened seats and without additive will eventually have the valves which are made from a harder material damage the valve seats. That,s why you see a valve mainly the exhaust valve sunk down low into the seat in the block. It has not had the lead to lubricate it and has beat it,s way down and damaged the seat. Share this post Link to post Share on other sites
RideRed 0 #30 Posted August 21, 2009 and one more thing i did'nt see... gas actually looses it's octane level as it sits. this is usually not a problem because in cars and at the pump it is used up so fast you would never notice. but if your like me and have several fuel cans for my outdoor equipment it might sit around for awhile. so that 93 octane fuel after as little as 30 days is now 89. yes i use stabil, but some of you may not. this is also why you should'nt leave fuel in the mower over the winter and/or why it runs like crap if you do. cause even high test after 6 months is horrible. just a tid-bit from the new guy. i'm also a Harley mechanic so i see this all the time with motorcycles. the bar room debate over octane rages on... Share this post Link to post Share on other sites
WheelHorse_of_course 99 #31 Posted August 25, 2009 Steve, thanks once again for the education. After reading your post I realize that going uphill with the deck going (just a short but steep hill) I get what certainly could e considered "knocking/pinging". I have now tried 89 with little to no change. I will try high test next time I fill my gas can and will be interested to see if it makes a difference. :thumbs2: Share this post Link to post Share on other sites
norman 0 #32 Posted August 25, 2009 It made a world of difference in my Cub Cadet 25 hp Kawasaki though..... IT did smoothin the idle and easier to start.... Share this post Link to post Share on other sites
oldandred 15 #33 Posted August 25, 2009 here we go again the gas thing hummm Ive always used the 87 and never never had a problem with it out of all of tractors and four autos one pic up one van well two vans forgot the work van heck it even burns good when starting fires :thumbs2: Share this post Link to post Share on other sites
TT-(Moderator) 1,128 #34 Posted August 25, 2009 I have a little K-181 Kohler here that likes nothing less than 100LL avgas. Share this post Link to post Share on other sites
WheelHorse_of_course 99 #35 Posted August 26, 2009 TT What? no nitrous bottle! :thumbs2: Share this post Link to post Share on other sites
Raider12 13 #36 Posted August 26, 2009 After reading this post original back in May, I had to give this some thought. I had plenty of the 87 octane on hand at the time, so I had to wait a little while before giving this a try. And I have to say I am impressed...... this o'l Raider runs without a single hiccup or cough and it is as powerful as I can expect it to be. I now run the 89 octane and will never go back. Share this post Link to post Share on other sites
dcrage 621 #37 Posted January 6, 2011 Heh Steve (wh500special), Would you comment on RideRed's assertion in his 10/21/09 posting about "octane degradation" -- Is that real?? -- Isn't the major difference between 87 and 92 octane the chemical structure of the molecules of fuel coming of the refinery tower (I alwasy assumed they were different distallation cuts) -- I can't imagine those molecules changing structure at ambient temperatures -- I could understand the additives blended to a batch of fuel coming out of solultion over time -- Do the additives used for octane enhancement have solution stability issues and is that the cause "octane degratdation"?? Share this post Link to post Share on other sites
W9JAB 156 #38 Posted January 6, 2011 http://www.wheelhorseforum.com/index.php?...ike+an+old+fuel Share this post Link to post Share on other sites
SkyhawkTL 19 #39 Posted January 6, 2011 In our big engines we used to mix up some 110 avgas, hydrazine, and a few other fun things and was it HOT - and it tested out legal in NHRA. Steve - thanks for bringing your expertise to the table - great discussion. There are many sharp people on this topic - and they are all willing to share. :banghead: Share this post Link to post Share on other sites
wh500special 2,055 #40 Posted January 7, 2011 Heh Steve (wh500special), Would you comment on RideRed's assertion in his 10/21/09 posting about "octane degradation" -- Is that real?? Hmmm...I don't really know. But it doesn't sound right to me. Here's what I think is happening when gas sits around: As the gas sits in a container, especially a vented container, the stuff with the highest vapor pressure evaporates first. That would be the lightest (shortest) molecules in the tank. So you'd start losing things with 4, 5, 6 etc Carbons first. The heavier - more difficult to vaporize - material sticks around longer. These are the octanes, 9, 10, 11 carbon molecules. And the alcohols. As the lighter stuff leaves the liquid phase the concentrations of the heavy materials that are dissolved in the gasoline eventually reaches a saturation point and things start to drop out. Coupled with oxidation products from the oxygen in the air leaves behind tars and varnishes. So, two problems crop up simultaneously. 1. The fuel is harder to vaporize in the carburator and burns poorly. It may make it very difficult to start the engine as well. 2. The solids and thick gooey stuff clogs up passages. I don't think the octane level of old gas would decrease. It probably goes up since the higher weight compounds should take more energy to autoignite. I'll have to think about this a bit more since I've never really given it any thought. Perhaps our analytical chemist from south of St. Louis will have some input. Sorry I can't be more helpful, Steve Share this post Link to post Share on other sites
dcrage 621 #41 Posted January 7, 2011 Steve Thanks for the reply -- The "analytical chemist" isn't going to be any help, because he is the one asking the question -- Your explaination makes some sense to me, especially the oxidation part -- The evaporation part I was a little suprised by -- But I wasn't thinking about vented containers -- What percentage of an 87 octane blend would be those short chain hydrocarbons -- I never noticed that much loss in a container of gas sitting in my garage -- But I never set out to measure how fast it was evaporating Share this post Link to post Share on other sites
buckrancher 2,678 #42 Posted January 7, 2011 Shouldn't we be putting lead addative in these, as to not burn out the valves?? These were designed before unleaded came out. Yes it might run better, but as what cost? When a two stoke motor comes to the end of the tank and runs on straight gas, it runs great, but... only on pre 1973 motors Chris Brian Share this post Link to post Share on other sites
hoppy 0 #43 Posted January 7, 2011 i dont run anything lessn then 89 octane in everything i own. My bass boat gets the high test.....150 mers arent cheap! piece of mind to put the good stuff in and the boat seems to like it. sleds get 89 when i actually get to ride them! Share this post Link to post Share on other sites
Horse'n Around 22 #44 Posted January 7, 2011 and one more thing i did'nt see... gas actually looses it's octane level as it sits. this is usually not a problem because in cars and at the pump it is used up so fast you would never notice. but if your like me and have several fuel cans for my outdoor equipment it might sit around for awhile. so that 93 octane fuel after as little as 30 days is now 89. yes i use stabil, but some of you may not. this is also why you should'nt leave fuel in the mower over the winter and/or why it runs like crap if you do. cause even high test after 6 months is horrible. just a tid-bit from the new guy. i'm also a Harley mechanic so i see this all the time with motorcycles. the bar room debate over octane rages on... When I was racing MX I had been buying VP before I started using 100LL av gas and I was told by service manager at the shop that sponsored me that if I was going to store it for a while its best to store it in a metal container than plastic to keep the fuel fresh. He also said that sunlight exposure can cause it to lose potency. John Share this post Link to post Share on other sites
Forest Road 594 #45 Posted January 7, 2011 A few years back I burned up two chainsaws back to back . I was running 93 oct fuel from Joe blow gas station. And a low end oil mix. I picked up an ethanol test kit and found high levels of moisture in the fuel. I later got in touch w/ someone from Stihl. He informed me that they TEST RUN ALL of their power equipment w/ Sunoco 94 octane fuel only. Through Stihl's testing they've determined it to be the most consistent and cleanest fuel in North America. Since then I only buy 93 oct from the name branded gas stations for my 2- stroke equipment. And have switched to Amsoil Dominator oil. And after havingread many of the posts here I'll buck up for the 89 oct on all of my other 4-stroke equipment. Share this post Link to post Share on other sites
