Redmax trimmer not running at full power

Discussion in 'Mechanic and Repair' started by Larson Lawn Care, Apr 13, 2010.

  1. Larson Lawn Care

    Larson Lawn Care LawnSite Senior Member
    Posts: 738

    In the past when my trimmer would run slow, I'd pull off the exhaust and clean out the carbon build up behind it and change the spark plug. I cleaned it twice and replaced the spark plug but it is still running slow. When I hold the throttle trigger down and flip the choke up and down, it will run good. Any advice?
     
  2. GlynnC

    GlynnC LawnSite Senior Member
    Posts: 798

    Possible air leak--while running, spray carb cleaner or brake parts cleaner around the base of the carb--does this change the rpm of the engine? If it does, then you have an air leak and need to replace gaskets--or maybe just tighten carb mounting screws. If it's not an air leak, and not exhaust port/muffler carbon build up, then it'll probably be dirty carb. Try running Seafoam thru carb and in fuel--do a search on Seafoam--you'll find lots of hints.
     
  3. Larson Lawn Care

    Larson Lawn Care LawnSite Senior Member
    Posts: 738

    Thanks alot, I'll give it a try.
     
  4. GlynnC

    GlynnC LawnSite Senior Member
    Posts: 798

    I should also have ask if it still has the spark arrestor screen in the muffler--is it clean?
     
  5. Larson Lawn Care

    Larson Lawn Care LawnSite Senior Member
    Posts: 738

    it looks clean
     
  6. Larson Lawn Care

    Larson Lawn Care LawnSite Senior Member
    Posts: 738

    Sea foam maybe helped a little. I took the airfilter cover off and took a look inside. The plastic thing that turns inside there when choke is adjusted with the hole in it (not sure what it is called) but the hole is still slightly exposed when choke is off. Is it supposed to turn until you can't see the hole anymore or have just a little bit still open?
     
  7. Larson Lawn Care

    Larson Lawn Care LawnSite Senior Member
    Posts: 738

    Maybe my description was a bit hard to understand. In the carb, you can see the choke open for air I guess, the part is plastic and it turns to when you flip the choke on, and it closes when off, but the hole in the plastic is still exposed? Is that normal?
     
  8. GlynnC

    GlynnC LawnSite Senior Member
    Posts: 798

    Okay, I'm confused. Tomorrow, I'll look at a Redmax to see what you are talking about. I think you are talking about the barrel in a rotary carb--but you keep talking about it being the choke--will get back at you tomorrow.
     
  9. betmr

    betmr LawnSite Bronze Member
    Posts: 1,663

    I am going to suggest you Clean and rebuild the Carburetor. I think the hole you are talking about is the opening in the barrel, and it should be open some at idle, it opens more as you increase the throttle. It does the same thing as a butterfly throttle valve, changes air flow into cylinder.

    I think the little reeds in the Carb. are sticking or stiff, and the inside of Carburetor needs cleaning. That's my opinion.
     
  10. Larson Lawn Care

    Larson Lawn Care LawnSite Senior Member
    Posts: 738

    I just bought a shindaiwa 282, now I have time to fix the redmax and have it for a backup. I was talking about the barrel. I did shoot carb cleaner through there and it seemed to help for a little while, but it is back to running slow.
     

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