Lesco ChemLawn Spray Gun Repair; What's Your Secret?

Discussion in 'Pesticide & Herbicide Application' started by SamSchlotz, Jan 18, 2018.


Which spray gun do you prefer (for blanket herbicide in CSTG)?

  1. Lesco Chemlawn

    7 vote(s)
  2. TeeJet 25660

    3 vote(s)
  1. SamSchlotz

    SamSchlotz LawnSite Member
    Messages: 75

    Who out there has been repairing/rebuilding Lesco spray guns with a high success rate?

    I perform ALL of our maintenance (Building and Equipment) and somehow, this project has repeatedly frustrated me, more than any other...

    My experience has been as follows:
    -The gun has begun to leak an unacceptable amount of fluid from the tip. Inspect, and Re-Build.
    -Following a nice long soak in warm water, it's time for a test. With the exception of one repair, every gun has shown little/no improvement, or failed again after 1-2 weeks use.

    Some folks have said all guns are throw away items. I'm from the school of thought that finds this unacceptable, so please... Someone.. Anyone....
    Tips? Tricks? Videos? I know someone out there isn't telling the rest of us the secret..
  2. ted putnam

    ted putnam LawnSite Fanatic
    Messages: 5,249

    At $70 per gun(not including the tip), guns are not a throw away item IMO. If someone is throwing them away after the original trigger mechanism fails, they need to throw them my way. There's only one or 2 secrets I know of for rebuilding/ using these (Lesco) guns. #1 always put a light coating of vaseline on the stem/plunger where the O-rings of the plunger and the plunger seal slide up and down on each other.#2 As the plunger is fed into the throat, be sure to "seat" the seal in the throat while still allowing the plunger stem to slide up and down. Other than that, occasionally it becomes necessary to run a cleaning brush through the throat of the gun( residues from overly thick or dry formulations of product can build up preventing the black stopper at the end of the stem from sealing in the throat. This will allow the gun to "dribble" if not clean and sealing properly. The rebuild kit includes springs and screws but I only replace these when I feel it is necessary.
    The only other secret I know of as far as Lesco guns are concerned is that somtimes the trigger seems "gummy" and doesnt want to shut off immediately. Holding the gun in the air with the trigger engaged, take the tip off and spray WD-40 down the barrel of the gun. Work the trigger back and forth until you get a crisp, spring loaded shut off.
    Hope this helps
    americanlawn, SamSchlotz and hort101 like this.
  3. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 15,163

    Take the handle screws out. No need to buy the kit. Just buy the small o-ring--I think there are two. This part fails first. Fluid leaks out of the handle. They are about a quarter-inch in diameter. Take them to your Ace hardware store and match them. You have to stretch them a good bit to get them over the shaft of the valve stem, of course. Need strong fingers. Lube everything up with grease--silicone grease is better; it is waterproof. Once it is well-lubricated, the shut off is not slow or sticky. Replace the whole valve shaft if the rubber dimple at the top has a visible groove in it.
    These small o-rings do not seal well when the weather or water is cold.
    americanlawn, hort101 and SamSchlotz like this.
  4. TPendagast

    TPendagast LawnSite Fanatic
    Messages: 14,573

    we're talking volatile (and expensive) chem distribution here.
    a replacement gun is the cost of doing business.
    You're not "saving" or making money fiddling around with beat up guns.
    Go rebuild an engine or something... hassling with a plastic gun isnt worth it and the spray tech will highly appreciate (and be more productive) with a new gun.
    grenskpr and phasthound like this.
  5. ted putnam

    ted putnam LawnSite Fanatic
    Messages: 5,249

    Hmmm...I never read the words "beat up" anywhere.
    I have Lesco guns that are 6-7 yrs old that get a <$10 repair kit 1 or 2 times a season. Ours aren't "beat up". We try to take care of them. They are $69.99 all day long at Westheffer. The tips are $10. I know that because I just replaced one that was several yrs old with a cracked barrel from this cold weather. If I trashed a lawn gun every time the gun started F'ing up, I'd be out $140/yr...at least. In 7 yrs, I'd have spent $980 minimum. Instead, I've actually spent less than $100 in repair kits and I have to replace a tip occasionally. It takes all of 5 minutes of my time when they do mess up to install a repair kit and I'm "back in business". The business of making money, not spending it unnecessarily. Very important. Especially when out in the field.
    I have a couple of 10-12 yr old Lesco guns in the shop that I would classify as "beaters" that stay in a box on standby but guess what, they work perfectly when the guts are replaced and they have the necessary tip. JMO
    americanlawn, SamSchlotz and hort101 like this.
  6. SamSchlotz

    SamSchlotz LawnSite Member
    Messages: 75

    Thanks for the input Riggle!
  7. SamSchlotz

    SamSchlotz LawnSite Member
    Messages: 75

    I appreciate the feedback! Im rebuilding another four next week, so we'll see how she goes...
    hort101 likes this.
  8. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 15,163

    In the instructions to rebuild--you can see the two quarter-inch rubber o-rings that are easiest and cheapest to replace.
    I just remembered--the valve "SEAT" is a bit difficult to remove. The rebuild kit does not include one, a doughnut-shaped white nylon washer thing with an o-ring around it. $11 additional. The rubber dimple seats against it to form the seal. Deep inside. Most of the time you can ignore it--no need to replace. There is a special tool to remove it. The pictures suggest a "pick". Not always easy. Too tight, I broke my pick tool. Most of the time you can ignore it --no need to replace.
    I had good luck with the valve seat a few years ago during winter refurbishment. I clamped a 6 inch-long, quarter-inch bolt in a vise. I eased the bolt head through the doughnut hole and hooked it on the bolt head. Gave her a yank. Out she come.
    Greased it thoroughly during re-assembly. Wanted to make it easier next time.


    The rebuild instructions.

    Last edited: Jan 19, 2018
    americanlawn and SamSchlotz like this.
  9. SamSchlotz

    SamSchlotz LawnSite Member
    Messages: 75

    I have the tool kit, and absolutely, it is still difficult to pull! I like your idea.

    Do you think that there is anything to be gained storing them in water over winter? Our warehouse stays around 60', but that dry, winter air?
  10. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 15,163

    I never stored mine in water. Stored outside like everything else--unheated shed.
    Of course, one of the most often broken parts is the trigger. The top inch most often snaps off. Still usable. Replace the white nylon trigger over the winter. At times it is possible to bend or break the white nylon hose connection nipple. 3/4 pipe thread to half-inch hose nipple.

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