Help me get this BR400 running

Discussion in 'Mechanic and Repair' started by keith.mcginnis, Oct 29, 2012.

  1. keith.mcginnis

    keith.mcginnis LawnSite Member
    Messages: 55

    Looks like i have some reading to do from Fluke. When I had the coil out originally, I wanted to test it with my multi meter but didn't know the proper procedure or readouts.
  2. BigFish

    BigFish LawnSite Platinum Member
    Messages: 4,192

    I wouldn't depend on the link that "58' supplied, it has to do with points triggered magnetos, which have nothing in common with Stihl's coil! There is no bench test for Stihl coils.
    Also, I doubt very much that out of adjustment valves are your problem, especially when you consider the BR400 is a two stroke unit!
  3. keith.mcginnis

    keith.mcginnis LawnSite Member
    Messages: 55

    LOL. Man he's just trying to help.
  4. keith.mcginnis

    keith.mcginnis LawnSite Member
    Messages: 55

    Do you guys believe an old Air filter would keep it from running? If I remember correctly, the one time it did run (2mins) I didn't have the air filter on.

    Would no air filter cause them to be hard to start? (Just for testing purposes)
  5. rbljack

    rbljack LawnSite Senior Member
    from Texas
    Messages: 731

    it didnt say in your original post, so I'll mention this first. You said it fires briefly when spraying starting fluid or some other combustible into the carb, then dies right? One question about the it new fuel, or the stuff that was in it when you got it? If its old, Id flush it all out and try start over with a clean mix.

    If the fuel is good because you know the mix is right, and its not been sitting for a long time, then Id suggest replacing the whole carb. If its starting briefly with the starter fluid (or whatever you used), it sounds like a carb probelm or fuel delivery problem still.

    Good luck
  6. keith.mcginnis

    keith.mcginnis LawnSite Member
    Messages: 55

    You are right I did forget to mention that. This is the same gas I use in My Kaw Trimmer, Husq Blower, etc..

    Normal trouble shooting would lead me to replace the carb, but it doesn't really explain why the plug gets soaked. There isn't much to this carb, I've broke it all of the way down and replaced everything.

    Thanks for everybody's ideas. Keep them coming and I'll try some things next chance I get.
  7. joe billy

    joe billy LawnSite Member
    Messages: 35

    120 psi should be enough to start and run OK.
    Pinch off the fuel line and pull the rope till it starts. If it starts then the carb is flooding.
    If it doesn't start , then you either have a spark issue or leaking crank seals or headgasket.
    Did you get the coil gapped correctly. ? Did you check for any side movement on the flywheel when you checked the key ? Is there any crank noise when you pull the rope ?
  8. rbljack

    rbljack LawnSite Senior Member
    from Texas
    Messages: 731

    I went back and read your inital posting again. When you did the carb rebuild, you swapped the gaskets and diaphrams correct, but what about the needle valve assembly itself? From what I know on those kits, they can come two different ways, one is with the diaphrams and gaskets only, and the second rebuild kit will contain those, plus the screen, and the needle assembly as well. If the needle valve is not operationg correctly, i think it could cause the problem your seeing ( a wet spark plug). Even if you change those out, there can still be problems in the carb that you cannot overcome with a rebuild kit such as the welch plugs, and the small orfices that cannot be cleaned very easily. Everything im reading says carb problem. Because you got the unit given to you, i'd shell out for the whole new carb assembly at this point and see where that gets ya. It probably wont be too much more than the rebuild kit cost ya.

    good luck, and please post the results of what fixes this blower in the end.
  9. keith.mcginnis

    keith.mcginnis LawnSite Member
    Messages: 55

    Well I went home last night filled the gas tank up and replaced the air filter. People everywhere say, check the air filter. I find it hard to believe a dirty air filter would keep it from starting, maybe just a loss of power. Anyway, I sprayed a little starting fluid in the carb and sputtered and died. I had maybe thought that the tank wasn't venting so I cracked the cap and continued to pull. I pulled about with choke on, choke off, same results either way.

    EXCEPT!, This time when I pulled the plug I noticed it WASNT wet.? So now I'm really confused. Before I try anything else. I'm going to put a small zip tie on the gas line at the carb (air leak) and try again.

    JOE, I didn't check for side movement. You mean like crankshaft play? Also, sometimes there is some weird noise when pulling the rope. Not all of the time, but it just sounds like a piece of rust in the muffler to me. Are you saying that just because compression is good that doesn't mean there is enough crankcase vacuum to pull gas through the carb properly?

    Yes I replaced the Needle and screen along with the diaphragm. See the link below for a picture of what my kit consisted of.

    K10-HD Carb Kit

    Keep them coming :drinkup:
  10. Richard Martin

    Richard Martin LawnSite Fanatic
    Messages: 14,699

    Check and make sure the fasteners holding the cylinder to the crankcase haven't come loose. BR400s are famous for that. There are also seals and gaskets in the crankcase, if they are bad then the blower may not start up and even if it does, it won't have any power.

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