Discussion in 'Lawn Mowing' started by Mowman, Jun 11, 2000.

  1. Mowman

    Mowman LawnSite Senior Member
    Messages: 553

    Here's what I found out today. I've had my 21" Toro Commerical Mower w/ the 4.5 Suzki engine and have been running Marathon 89 Octane w/ Husquvarna XP Oil for a year. The other day it started knocking and pinging sounded like it was coming apart. Took it to the dealer and the mechanic said he did not know what was wrong until he opened it up. So he called the head mechanic at Toro and he told him to tell me to run 89 Octane Shell gas in it,and if that does not take care of it they would give me a new mower. Yea right WHATEVER!!!. So this morning I drove across town to Shell,filled the tank with the 89 Octane Toro suggested. Got home and started to mow. I mowed for about 20 minutes with the banging and poping still going on the motor reving up and down and then all of a sudden it smoothed out and started running just like the day I brought it home. So what the heck is up with that? Anybody out there know why this is? Will let you all know if this has really taken care of my problem. I'm still in shock. Thanks for your input. Mowman
  2. coldbrook landscapin

    coldbrook landscapin LawnSite Member
    Messages: 16

    mowman I used super gas( 91 octane) in all my gasoline motors even my 2 strokes been doing this for about 6 years now any haven't had any problems. been told that super Or premium gas burns cooler and cleaner. Of course its costs more usually 10-15 cents more , however i beleve its better in the longer run with less break downs
  3. thelawnguy

    thelawnguy LawnSite Silver Member
    Messages: 2,411

    The octane rating might be different, but the fuel you buy at Shell came from the same storage tank, and maybe the same tank trailer, as the fuel at Mobil, Chevron, Citgo, Shell, Cumberland Farms, etc.<p>A friend of mine drives a truck for an oil distributor, same gas goes to all the stations, he lets me know, however, when he had to dump a remaining load of super into the regular grade tank (if the storage tank is full, the load needs to go somewhere, its ok to mix the super with the regular but not vice-versa) at a station so I can fill up with super at regular prices.<p>Bill
  4. bdemir

    bdemir LawnSite Senior Member
    Messages: 610

    Bill,<p>Its hard to believe thaty every gas staion uses the same gas. I dont think that marathon uses the same as mobil. Clark and sppedway and the small gas and go spots around here are considered not the same as the big gas sellers like shell mobil and so on. I dont know for shure but there is such a thing as cheap gas and good gas. I do tend to think that there is a difference between the good ones and the bad ones.Just not positive about it. I use highest octane always and never had a fuel related problem yet.<br>
  5. Keith

    Keith LawnSite Platinum Member
    Messages: 4,003

    The additives are what make gas different from company to company. Mowman, it is a bit odd that it knocked and ran like crap on a particular gas, but it happens, could have been a bad tank. Stay away from that brand, but don't limit you fuel to Shell.
  6. Guido

    Guido LawnSite Silver Member
    Messages: 2,087

    Bill is right! My uncle owns a Gulf station and talking to the truck driver that delivers the gas, he delivers to the mobil and exxon right down the road with the same product!! 87 octane is 87 octane wether mobil, exxon, sunnoco, etc? Maybe your just having luck with the mower. It doesn't make any sense unless you changes the grade of gasoline your using.<p>----------<br>&quot;guido&quot;<br>David M. Famiglietti
  7. Charles

    Charles Moderator, Friend, Angel
    Messages: 11,810

    Maybe one station has cleaner newer tanks than the other.<br>Just a guess
  8. kenneybros

    kenneybros LawnSite Member
    Messages: 49

    Coldbrook not true. Higher octane takes more time to ignite.. when your engine is designed for 87 the excess carbon that doesnt burn builds up causing &quot;constapation&quot; in the muffler. This happened to both my trimmers... one was a shindaiwa. After about a month of using them on 94 they would just stop running. now i use 87 in my trimmers. My husky chainsaw however is designed to run on at least 92 octane, leaded or unleaded(to keep it cooler, like you said) So basically you just have to run what is specified and if you dont.... just know how to fix the problem it causes(like cleaning the spark arrester screen)

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