Old Honda mower started fluctuating and then died

Discussion in 'Mechanic and Repair' started by PatrickGSR94, Jul 28, 2013.

  1. PatrickGSR94

    PatrickGSR94 LawnSite Member
    Messages: 32

    I have an old Honda self-propelled mower that is over 20 years old, used every season and has had almost zero problems with it. It's always started on the 2nd if not the 1st pull of the cord, every year, every use.

    However suddenly today while I was mowing the engine RPM started fluctuating wildly. It sounded like it was only getting spark (fuel igniting) every 10 engine revolutions or so. It would ignite a few revolutions, and then the engine would start spinning down, then ignite a few more revolutions, etc. It did this for a couple of minutes, and then just died completely.

    Fuel is in the tank, and the fuel shutoff is fully open.

    I let it sit for about 1/2 hour, then tried again. It seemed to start, RPM all the way up to normal range, but only for a few seconds, then it died again.

    The air filter could stand to be cleaned, but I tried starting it with no filter and it just did the same thing, started for a few seconds and then quit. And then on top of that the pull cord spring decided to break after trying it that last time.

    The mower is an old Honda SX model, the HR-215. It has 3 self-propel speeds, and also a blade clutch, so there are separate blade control and self propel control handles.
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Sounds like a piece of trash got sucked up in the main jet restricting fuel flow, Clean the carb and try running again...... After you repair the recoil......
  3. PatrickGSR94

    PatrickGSR94 LawnSite Member
    Messages: 32

    Well I was just now able to get it to start and run, but with the throttle in the Choke position. I started it with my corded drill. With the throttle on the fastest engine run speed, the engine dies. But on Choke it seems to run normally, although the RPM seems a little high.

    It does not sound like there's any kind of air intake restriction when the throttle lever is on Choke. When I first started it this morning, Choke was working just like it should (cold engine start, engine runs a little rough, then pull lever back to the fastest engine running RPM speed). But now it's acting like Choke doesn't work properly.

    Something out of adjustment with the throttle/choke linkage and cable perhaps?
  4. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,337

    Ditto...RestroRob....trash in the carb....
    Might want to change the sparkplug...if its 20 yrs old...
  5. PatrickGSR94

    PatrickGSR94 LawnSite Member
    Messages: 32

    lol no it's not that old, a little bit of maintenance has been done on it :p The spark plug and air filter both are about 2 years old I think.

    Isn't the purpose of the choke to block off the air and enrich the A/F mix to help get it started when cold? If so then why would it be running smoothly when the throttle lever/cable is on the Choke position?
  6. herler

    herler LawnSite Fanatic
    Messages: 5,139

    You could always put it out of its misery and shoot it.
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,337

    The reason it is running smoothly on choke is because the main jet is partially clogged.
    Choking it increases the vacuum on the carb...sucking more gas....
    If the mainjet was unobstructed...and the choke stayed on...you would flood out the engine..
    It would stall...
  8. BigFish

    BigFish LawnSite Platinum Member
    Messages: 4,186

    So what part don't you understand ?????

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