Problem: Engine dies when adding throttle

Discussion in '4-Stroke Engines' started by Bill555, May 19, 2009.

  1. Bill555

    Bill555 Member

    I've got the 33.5 subaru. The engine starts and idles well. And runs ok with just a little throttle. But dies with more. I tried changing the plug. Which didn't help. Any ideas?

  2. machiasmort

    machiasmort Active Member

    Make sure the head bolts are snug but don't overtighten (strip) them.

    Let me know how you make out.
  3. Happy Valley

    Happy Valley Active Member

    Hi Bill
    How old is it and how many miles/hours you got on it?
    Was it in storage?
    Those answers would help long distance diagnosing. :D

    Rough guess: sounds like it's being starved for fuel/air.
    Things you could check are, something in this order:
    air filter
    fuel filter
    bad fuel
    dirty carb
  4. Bill555

    Bill555 Member

    thanks for the replys.

    Happy Valley, I got it early last year and rode a season. I didn't put a terrible amount of miles on it last year. The engine hasn't had any real maintenance besides half a dozen oil changes and the spark plug I tried. In the winter I did start it once a month and topped off the tank with fresh gas.

    Lately the bike has been peddled some without the motor on. I'm wondering if this could have dried some gas in the carb. It had been peddled for a few hours at a time. In high wind.

    I've also had some trouble with the gas tank with this engine. The rubber where the tubes go into the tank doesn't fit snugly and leaks gas out. I've used epoxys which seem to work for a while, but it is obvious I'm not using the right product for the job. I kind of doubt this has anything to do with the problem I'm having now. But this blob of epoxy makes looking at the fuel filter a bit difficult. But the tank looks clean.

    Maybe tomorrow my buddy can help me clean the carb.
  5. eastwoodo4

    eastwoodo4 Member

    its a dirty carb dude.
  6. HoughMade

    HoughMade Guest

    That is correct. It is starved for fuel.

    Dirty filter (take it out and check) or carb. Once you get it figured out add a see-through paper based filter and the problem should not return (if you don't have one already).

    Also- hose clamp good- goo or epoxy- bad.
    Last edited by a moderator: May 19, 2009
  7. machiasmort

    machiasmort Active Member

  8. Happy Valley

    Happy Valley Active Member

    Bill I forgot to ask, what did the plug look like that you took out?
    Light/dark, clean/carboned ?
  9. Bill555

    Bill555 Member

    Well, it was a dirty carb. Thanks for the help.
  10. Happy Valley

    Happy Valley Active Member

    Good to go then.
    I'd be curious to know what you did to clean it.
  11. Bill555

    Bill555 Member

    Happy Valley, when the carb was opened, there was just dirt behind the screen. In the future, I just need to be more careful about not using gas from cans that don't have much gas in it.
  12. Bill, Read the manual concerning storage. They want you to empty out the fuel tank and run the engine till the carb is empty of gas and dry. Then remove the plug and squirt a few drops of oil in. Also change the oil after running it dry. Starting an engine, then shutting it down before it reaches full operating temp is bad for them. The seal where the gas lines pass through the tank can best be resealed with a silicon sealer made for sealing gas leaks, available at autoparts stores. It stays flexible and won't crack with vibration like epoxy will.