Shindaiwa T-270 compression - what's good?

Discussion in 'Mechanic and Repair' started by Jason Pallas, May 26, 2007.

  1. Jason Pallas

    Jason Pallas LawnSite Bronze Member
    Posts: 1,325

    Quick question - checking one of my Shindaiwa T-270 trimmers... what is the acceptable compression?
    I get about 65psi on the first pull - then it jumps to about 90psi on the second pull and tops out at 125psi on the 3rd or4th pull. Is this within range?
     
  2. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    Sounds good to me. Are you having issues with it?
     
  3. thethirstymoose

    thethirstymoose LawnSite Member
    Posts: 75

    I'm suspecting some issues with my trimmer, so I did a comp. test cold was #120 let it run for ten min or so and took a hot test and it's down to #110 so I'm losing compression as it get hot this explains why it boggs down.......so what to do.I'm thinking of replacing the rings, replacing the head gasket, and possibly the crankshaft seals......any other ideas? Not sure if the cylinder is bad, but this trimmer runs good and starts good, idles good, so I dont think the cylinder would be bad, otherwise I don't think it would start
     
  4. Jason Pallas

    Jason Pallas LawnSite Bronze Member
    Posts: 1,325

    You're fine. Clean out the carb - these carbs are notorious for getting clogged up. Thoroughly clean it with air and carb cleaner. There is one particular jet that gets clogged - I'll look for a diagram to try to show you which one (it's under the plate in the float diaphragm area - held in by a phillips screw.
     
  5. thethirstymoose

    thethirstymoose LawnSite Member
    Posts: 75

    Are you sure? Here's my thing.......Not sure it's the carb, because it starts fine, runs fine, could idle all day long....I go to use it, and all of a sudden about ten to fifteen min. no power, and to keep this thing running, the screw that controls the idle/mix is all the way in.....which isn't normal, but if I back it out, it wants to die.........show me your diagrams if you have them.appreciate it
     
  6. dboyd351

    dboyd351 LawnSite Bronze Member
    Posts: 1,100

    Does it only start running like crap after it has run awhile? If it runs good at first, then looses power later, it might be the coil/ignition module. I've heard after they heat up they can start missing.

    I think your top end is fine or it wouldn't start and run well at first.

    Maybe a real mechanic will come along with a better answer after they quit laughing at the Seafoam thread.
     
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Sounds like an air leak....
    Look for any buildups of crud around the head or crank.
    Remove the insulator block that the carb mounts to and see if the gasket is wet.
    Posted via Mobile Device
     
  8. dboyd351

    dboyd351 LawnSite Bronze Member
    Posts: 1,100

    Slapper,
    Wouldn't it run bad when you first fired it up if it had an air leak? Best I can tell, he said it ran good at first and only started running bad after 10-15 minutes of run time.
     
  9. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Things are not always as they seem...
    As the engine heats up and expands, the crud that was sealing the leaks becomes pourus.
    Posted via Mobile Device
     
  10. ffemt1271

    ffemt1271 LawnSite Bronze Member
    Posts: 1,285

    Had one that ran bad after a few minuted, i replaced the fuel cap and it ran fine
    Posted via Mobile Device
     

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