Is this hard on a engine???

Discussion in 'Mechanic and Repair' started by lawnchopper, Jul 24, 2004.

  1. lawnchopper

    lawnchopper LawnSite Member
    Messages: 211

    starting and stopping the engine at full throttle??? engaging and disengaging the blades at full speed?? some of my co-workers do this to our mowers and it bugs me the engines will be running for hours and they will pull up and shut everything down at once.
    Sometimes they start it up cold at full bore aswell. I also tell them to let the motor idle for about 20 sec and shut the blades offf at half they just dont get it. We get alot of backfireing in our Kohlers what will backfireing long term effects be??? our Kaw's never backfire. Our Walker backfires if I let it idle before shutting in off but when its shut off at full throttle in doent:confused: This cant be good either
  2. ducky1

    ducky1 LawnSite Senior Member
    Messages: 252

    Any kohler that has a fuel shut off solinoid on the carb should be shut off at about 1/3 to half throttle to prevent backfire. Have seen holes blown in mufflers before due to backfire. A engine should not be started up at full throttle because of not having oil pressure up. It runs the engine without oil until the pressure hits the bearings. Better to start at a idle so engine makes fewer revolutions untill it gets oil. Sone of my co workers does the same thing and it bugs me too. They dont have to fix them, I do.
  3. fixer67

    fixer67 LawnSite Silver Member
    Messages: 2,098

    "stopping the engine at full throttle??? "
    You are going to get as many different answers to that as people you ask. I am a MST for Briggs and I can tell you that this is a question that is not going away any time soon. You can pick up any book or manual for any engine and it will tell you one thing then get another one for that same engine and it will tell you the opposite. Here is what I tell people, shut it off at idle if possible but if it starts to backfire shut it off just a little higher than idle. Keep shutting it off a little higher each time until the backfiring stops. Do what ever you have to do to keep it from backfiring. I have seen mufflers blown out, air filters blown out, once even seen the air cleaner blown OFF, cracked heads, damaged carbs(bowls blown off, floats smashed). The cause of all this mess is the EPA. The gas made now days and the lean burn carbs today are the reason for the backfires in the first place.
  4. Oldtimer

    Oldtimer LawnSite Bronze Member
    Messages: 1,459

    Always turn the blades on at low engine speed and turn them off at idle engine speed.

  5. Powell_Landscape

    Powell_Landscape LawnSite Member
    Messages: 9

    I am a mechanic at a local hardware/outdoor power equipment store and I'm new to lawn care, but not new to backfiring Kohlers. There is one simple solution to the backfiring that has worked for all of our customers. Shut the engine down at idle but as soon as the engine starts to die open the throttle to full speed position. I've seen many Kholer engines do this and this trick has always worked. If this makes no difference it may be time to check the valves for proper seating.
  6. Powell_Landscape

    Powell_Landscape LawnSite Member
    Messages: 9

    Also as far as starting and stopping the blades at full throttle nearly every manual I've read has said to engage an electric PTO clutch as full throttle. There are going to be endless arguments to that question but I usually engage about half throttle and go to full right after the clutch engages, this seems to be the smoothest and quietest procedure I've tried. As far as disengaging the clutch I usaully do that at full throttle.

    When it comes to reving an engine to 3600 RPM cold I would never do it. I usually start the engine as soon as I get to a job before I unstrap or unload the mower by the time everything is ready the engine has had a chance to warm up.

    Keep your Kohlers from backfiring or you will be investing alot of money into mufflers or worse.
  7. Oldtimer

    Oldtimer LawnSite Bronze Member
    Messages: 1,459

    Engaging the blades at WOT is like reving your truck engine and dumping the clutch. After a LCO thinks out what happens when the blades are engaged and has replaced a clutch he will learn how to engage and disengage the blades.

    I have not read a manual that recommended abusing any equipment.

  8. dlandscaping

    dlandscaping LawnSite Senior Member
    from mass
    Messages: 835

    My toro 36" has been backfiriing since day one. The only way to prevent this is to idle it for 30+ seconds. I dont have this extra time so I just shut it off quickly and yes it backfires. The 52" toro w/ 14hsp kohler I do the same with, except it never backfires. As for starting the mower, I start it on choke and then move it to fast and go. On properties that take under 20 minutes, 1-2 min to idle the equipment is a real pain. I engafge/ disengage the blades at full throttle at all times. I have not had any problems in 3-4 years with backfiring or worn out equipment.

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