Just got a Pole Saw HT 75

Discussion in 'Mechanic and Repair' started by MXHalofan, Jun 9, 2012.

  1. MXHalofan

    MXHalofan LawnSite Member
    Messages: 91

    Just picked up this old pole saw and want to know what I should look for. Looks like some play were the shaft off the power head meets the large boom shaft. Gonna take that apart later.

    Compression is 75 PSI, piston moves around a MM or so by feeling in the exhaust port. Figuring I'll run it for the rest of the season (bush trimming) and then should I replace piston and rings or do these usually need cylinders, crank bearings? I didnt' see any scouring on the piston or cylinder through the port.
  2. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    If all you can manage is 75psi, good luck. I don't think you will find much two stroke hand held equipment that are spec'ed out less than 120psi.
  3. Patriot Services

    Patriot Services LawnSite Fanatic
    Messages: 14,506

    If all that's wrong is low compression then yes a new jug and piston would be a good investment. If the crank and cutting head are worn then you are looking at more in parts than a new one. Parts can be ridiculously priced. I agree with Dutch, 75psi is too low. May start, but power will be way down.:usflag:
  4. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,337

    News rings and a headgasket may buy you some time....not too expensive...
    75 psi might start when cold...doubt it would restart when warm...
    Posted via Mobile Device
  5. MXHalofan

    MXHalofan LawnSite Member
    Messages: 91

    Yea, I showed the seller the PSI reading and talked him down. Bought it right. Got lucky the guy was reasonable.

    It starts easy, idles and runs good. Missing a little torque down low while cutting. Cuts like butter though when you wring it. I'll see how it does with the hedge trimmer head on there.

    I'd have bought it for full price judging by how it runs. The saw head doesn't take as much power as a trimmer or hedger trimmer head. Glad I brought my compression tester. I'll probably post back up after I order a piston and ring set.
  6. dboyd351

    dboyd351 LawnSite Bronze Member
    Messages: 1,126

    The hedge trimmer heads don't generally require much power to run, maybe less than the saw.

    If it really runs that well, maybe your compression tester is off.
  7. MXHalofan

    MXHalofan LawnSite Member
    Messages: 91

    Maybe it was off. I was looking around for a replacement engine, and decided to test PSI cold. Got 120 LOL

    Gonna check PSI again hot. Is there normally a big drop in PSI when hot?
  8. dboyd351

    dboyd351 LawnSite Bronze Member
    Messages: 1,126

    I'm not sure how much difference you'll see cold versus hot, but I think if you are getting 120 psi it should run OK. If you are getting 75 psi, I doubt it would run well, if at all. My understanding is anything under 100 psi will probably not run decently.
  9. cgaengineer

    cgaengineer LawnSite Fanatic
    Messages: 15,778

    If it idles the crank bearing and seals are probably in good shape...if seals are bad it will suck air and not idle or idle well. It will also take longer to wind back down.
    Posted via Mobile Device
  10. MXHalofan

    MXHalofan LawnSite Member
    Messages: 91

    Thanks engineer.

    I'll check PSI hot tomo and see what the reading is. Maybe I didnt' have the comp tester tight enough. I cranked it a little extra tight this time around LOL

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