Tanaka 'Hot Start' problem

Discussion in 'Rack Mounted Engines' started by uncle_punk13, Mar 3, 2009.

  1. uncle_punk13

    uncle_punk13 Guest

    Hey all,
    When out riding my M/B, (rack mount Tanaka PF40) if I stop at a store, when I come back out (engine still warm) I have a heck of a time getting it re-started.
    Is anyone else having this issue, and what have you done to alleviate this? Is there a 'routine', or certain 'settings' I need to adhere to in this situation? When cold it fires right off with no problems, and runs like gangbusters (still in break in period) while cruisin' around. Just hard to start when warmed up.
    Any ideas?
    I did a thread search for this but came up with nothing; if this has already been addressed, please direct me to the proper thread...

  2. bamabikeguy

    bamabikeguy Active Member

    Hey Rif,

    Are you using mid grade/major brand?

    I went ages before cleaning the foam air cleaner on mine, that usually isn't it.

    And you haven't had it long enough to change plugs, I guess.

    Poor grade, or month old gas would be the easiest source.
  3. uncle_punk13

    uncle_punk13 Guest

    So I should try the premium? I always go with the lowest octane/price. I'll give 'er a go and see what happens. Thanks!
  4. Mountainman

    Mountainman Active Member

    when warmed up
    have you tried starting with just a slight chock ?
    just thinking possibly a little lean
    not noticed when starting cold because you are using chock ?

    have seen this problem before somewhere
    just not coming back into the minds eye at this time ???
    will be thinking on this ???

    governor not acting right ???

    ride the motor bike
  5. Zev0

    Zev0 Member

    Rif, I had that problem with my PF33. Changed the original champion plug to a NGK and no problems since then. In fact, hot or cold, now 1 pull is just about all it takes.
  6. mabman

    mabman Member

    Try starting it with a full crack of throttle. It works on chainsaws.
  7. jg767

    jg767 Member

    I had the same problem, I just cleaned the plug. Took care of it.
  8. bamabikeguy

    bamabikeguy Active Member

    I only had a 40cc Tanaka for about a month, and mabman's post
    reminds me of the emergency remedy, which was releasing the belt tension, using my "cruise control" wire to hold the throttle in about 1/3, then pull.....a friendly stranger could also help with that experiment, you hold the throttle in while he pulls the cord.

    When the ethanol legislation took effect last summer, I felt the effects immediately with the 87 octane, I use mostly Standards and Amocos. Moving up to 89 octane, NEVER using discount brands, got the performance back up to nearly normal.

    But when I had that 40cc, (this was way back in 2006 or 07, thousands of brain cells killed since then), it seems I had an "old batch of gas episode", and jg767's reply
    sparked a memory, because that plastic spark plug cover worked loose, and I had to pay .70 for the small metric bolt that went missing.

    A gummy spark plug would be easy to spot....
  9. uncle_punk13

    uncle_punk13 Guest

    Well thank you all for the replies! I sure do appreciate it!!!
    I have tried the choke in different positions, I have tried the throttle in different positions, and a combination of these with the same result. No pop.
    I'm gonna try the plug swap to the NGK (always had good results with NGK), and will stop using the lower grade gas... I never use 'off brand' gas; I usually go with Chevron, or Shell. It's a funny thing with these small engines and gasoline- My Tecumseh 49 friction didn't mind the lower grade gas, but my (Tanaka)Bike-Bug ran better and with more power on highest rated gas... Ah-Ha! Tanaka Bike Bug ran best on Higher grade Gas; Same company, so seems reasonable that the PF40 needs the same right?!?!?
    Again thanks my M/B brothers,
    Last edited by a moderator: Mar 4, 2009
  10. Happy Valley

    Happy Valley Active Member

    What carb do those run? I have a Mitsu 40cc that has a Nikki carb with a tickler on it.
    It hard starts when hot if I don't prime it repeatedly (no choke) and hold the tickler until gas runs out. I think the gas in bowl just vaporizes quickly after shut down when hot.
  11. bamabikeguy

    bamabikeguy Active Member

    That makes perfect Dr. Spockish logical sense.

    Any sane 40cc rider is running wide open, and that engine heat would be the mystery factor.

    Air cooled means "when stopped, no breeze"...
  12. az cra-z

    az cra-z Guest

    Agree with mabman, open the throttle wide, flooding is the cause.
  13. Hive

    Hive Guest

    Tanaka Start Issues

    Don't forget to let us know the results.

  14. seanhan

    seanhan Member

    on my Tanaka

    I never used the choke..
    Cold start just push primer bulb 3 times and pull
    Warm restart just pull.
  15. eastwoodo4

    eastwoodo4 Member

    i had this problem turned out to be the plug.
  16. augidog

    augidog Banned

    i've had plug-related starting problems, also. for one thing, the gearhead keeps trying to see how big a gap i can run. seems (to me) that .024-.028 is the best the cdi is gonna do. now, i just keep fresh plugs handy and stay at the recommended .024". it's difficult to tweak a stock engine that's optimised for emissions.

    when warm-starting the 40 i get my best results with no priming and a few extra pulls. i was having problems with a wet plug if i primed it.

    of course, it usually only doesn't-start if i have some beer in my pack...all shook up & noplace to go ;)
    Last edited: May 12, 2009
  17. Usually hot start issues on diaphragm carb motors I've seen are
    are most often caused by:

    1. the vent is clogged in the gas cap (try removing cap, then reattach, then try starting)
    It would create a vacuum in the gas line, not allowing fuel to flow to the carb.
    I mod my caps for a larger vent, so this does not happen.

    2. Clogged internal fuel filter in the carb.

    Check both.
    If you undo the cap after it's hot, and you hear "shhhhhhh"
    your cap isn't venting right.

    My Tanaka could flood easily as well, and I never prime it if it's warm.
    These lean burning tanakas are also succeptible to air leaks causing huge problems sometimes.
    Last edited: May 12, 2009