LawnBoy 21" experiences/asking for help

Discussion in 'Lawn Mowing' started by Roger, Jun 11, 2004.

  1. Roger

    Roger LawnSite Fanatic
    Messages: 5,943

    About six weeks ago, I bought a new commercial 21" LB SP to use in place of a Toro commercial (5.5 Sizuki). I posted a note about this change. After six weeks (about 30 gallons of mixed fuel, maybe 250 hours of work), some observations:

    1. The change was the right thing to do. The side-bagging LB works so much better in our environment. Heavy clippings, damp, wet, whatever ... the debris ends up in the bag, not the chute.

    2. The results of the mowing are very good. We've gotten compliments on our work. This was not a surprise because I had used an older LB, which we still use periodically.

    3. The Dura-Force engine is very efficient, running for perhaps 8 hours on a tank of fuel. Only a few times have we run it out during the course of a day.

    4. The quality of machine is very poor compared to the Toro, as a piece of equipment. A few items:

    a. The rear drive wheels have already lost about 70% of the tread. They will need replacing in another four weeks.

    b. The side bags had holes in the bottom after two weeks. I use two bags from the new machine, and two from my old LB, so the bags weren't being used full time. This is no real problem -- the old bags have had holes for a long time, and still work.

    c. My biggest complaint is the Dura-Force engine. The Sizuki engine works like a fine-tuned instrument, compared to the flaky Dura-Force engine. The notion of "one pull" start is a joke! This is not only true for a cold engine, but also for a warm start (trailering to the next job), or even a hot start (changing bags). The engine pulses at times, not always, and not predictable. This happens with a cycle of perhaps five seconds, faster, then slower, then faster, then slower.

    The power is OK, and the engine continues to run to get the jobs done. But, after living with the Suzuki for two seasons, I am less than impressed with the Dura-Force engine. My old LB is a model sold just before the Dura-Force was on the market (1998?). It has been used heavily over the years (5,000 lawns?), and it runs better, starts easier and more consistently, than the new one. Yes, it makes more noise, and yes, it has had many parts replaced, but the engine runs like a champ (100:1 Amsoil). I have tried the same Amsoil mix in the Dura-Force, but returned to 32:1 LB oil. I've read some threads where 50:1 Stihl has been used in Dura-Force, ... maybe I'll try a couple of tanks of that mix. I use 50:1 Stihl in all my Stihl hand tools this season.

    Anybody have any suggestions to make the Dura-Force run better?


    P.S. I did return it to the dealer and their word, "... this is the way they run." I don't believe that, but don't know what else to do.
  2. TLS

    TLS LawnSite Fanatic
    Messages: 7,943

    I have never, and I mean NEVER pulled more than twice on the rope to start ANY of my Lawnboys. That includes sitting all winter long, and the NON-Primer types.

    I have a newer Duraforce, and it starts EVERY SINGLE TIME on the first pull.

    Here's how I go about this.

    1) 3-4 pumps of the primer bulb.

    2) Set throttle to full choke.

    3) Pull starter rope.

    It starts immediately, and will smoke and stumble until you pull it off choke. Then I slam it to full power and MOW.

    So, something must be wrong with it to not start on first pull. You ARE priming it, right?

    Also, stop using LB 2-cycle mix. It's garbage.

    My biggest complaint is the lack of lift at the 3.25" (highest setting). The cut really sucks. All I use mine for is small trim work and a few dog runs with 30" gates.
  3. 1MajorTom

    1MajorTom Former Moderator
    Messages: 6,073

    We feel dirt gets in the carb very easily. On the muffler side of the engine on the carb, there is a long sticker about an inch long with numbers on it. Peel it off, you will see a jet needle. Unscrew it, and clean the needle with carb cleaner. And spray carb cleaner in the hole too. That usually will do the trick for hard starts.

    As for making the engine run better, turn the govenor which is located on top of the carb, it's a white knob a diameter of a nickle, turn it the direction that will speed up the engine. One way speeds it up, one way slows it down. You have to do this while the motor is running. You don't want to go more than 4 or 5 clicks though.

  4. 1MajorTom

    1MajorTom Former Moderator
    Messages: 6,073

    I believe you. However I believe you aren't using your LB like Roger is, so there really is no comparison. Your mower is going to stay in great shape for a long time. But with the amount of use Roger is using his, his is bound to be tempermental.

  5. Fareway Lawncare

    Fareway Lawncare LawnSite Silver Member
    from Canada
    Messages: 2,222

    Check Your RPM's on the Duraforce...the Duraforce Is More Powerful than the 5.5hp Suzuki...I have Several of Both...& Will Not Bog as Easily...

    ...Stitch the Holes in the Side Bag....Take off the Metal Plate Under the Discharge...Pray they Don't replace the Duraforce w/a Honda!
  6. DLCS

    DLCS LawnSite Platinum Member
    Messages: 4,386

    Turning the knob counter-clockwise will speed up the engine but if you turn it clockwise the spring has a tendency to come loose. You don't want that spring to come loose cause its a pita to put back in so just turn it clockwise a couple of clicks.
  7. DLCS

    DLCS LawnSite Platinum Member
    Messages: 4,386

    I thought that was already a done deal? I hope not though.
  8. jason r.

    jason r. LawnSite Senior Member
    Messages: 338

    Just bought a lawnboy with the duraforce engine. Had to return it because the engine was surging. The mechanic said that it was a normal problem they've had and adjusted the governer and replacing the spring. I'll get it back in a couple days and see how it works. That was the last duraforce my dealer could get. All the new ones will have the honda engines.
  9. grass_cuttin_fool

    grass_cuttin_fool LawnSite Gold Member
    Messages: 3,526

    My duraforce 2 stroke will surge for a minute or so till it warms up and then its ready to roll. 8 hours run time on 1 tank of fuel, I dont think mine would do that , maybe 1 hour and the tank would be dry
  10. Roger

    Roger LawnSite Fanatic
    Messages: 5,943

    An update .... (I know it has been a long time since the thread was started, but it is a rainy day here).

    I did advance the governor three (maybe four) clicks. That was a definate improvement. But, initially, it still surged and still didn't run as well as I expected.

    Now, we are over two months later, and the engine does run better. Why time improved the engine, ... I dunno.

    It still does not start as well as it should. I have my old pre-DuraForce engine to compare. The old one is a sure bet to fire first pull, all the time. That is not certain with the Dura-Force.

    By now, the mower has nearly 500 lawns behind it, perhaps 400 service hours, probably more. We were running about five gallons of mixed fuel per week (6 days), so the tank was nearly empty every night. Yes, the bags still have holes, held together with large safety pins. And, after eight weeks of use, the rear drive wheel were completely worn out (no tread, rubber splitting). They have been replaced. Based upon previous experiences with the old mower, the ground drive cable should be breaking soon now -- we will not be surprised. Some wire wrapped around the broken cable and attached to the handle bail will solve that problem. [No apology for the cynicism! I feel fortunate just to be able to work.]

    But, the machine has done a great job of bagging when needed (no needed recently with much drier weather), and the results of the cut are very good. We have done much more discharge work than expected, and that is welcomed. The Toro required bagging most of those jobs.

    Thanks for the inputs.

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