Engine Trouble Tanaka PF 3300 misses under load and uses excess fuel

Discussion in '2-Stroke Engines' started by ChrisB, Sep 17, 2014.

  1. ChrisB

    ChrisB New Member

    Awesome site! Just found it. This is my first post so please go easy on me!

    I have a GEBE setup with a tanaka PF 3300. Have had it 4 years and ride it approx 25 mi/day 3-4 days a week as commuter spring/ summer/ fall. So a lot of time and use.

    Last year it started acting up. Would lose power and miss/completely cut out under load. Seemed to be time or temp related as it would run well although not developing full power for like 10-15 minutes before starting to cut out. Also uses way more fuel running while doing this. I checked spark, replaced plug and it was all good. Compression is excellent hot or cold and whether or not the engine is having this problem. Tried to troubleshoot further but stumped me for a long time. I finally bought a carb rebuild kit from Tanaka because I was out ideas and things to try without replacing parts. Removed carb and carefully installed kit and re installed carb. Viola! Problem solved. But I never understood what it was about rebuilding the carb that corrected the problem. In other words I really never figured out what was wrong.

    Now a year later (and a lot more good miles) the engine is doing the same thing again. I am sure buying a kit and rebuilding the carb will solve the problem, but replacing carb kits frequently is not a good solution. I want to know what is going wrong and what if anything I can do about it for a longer term solution.

    I run ethanol free gas because I know that can wreak havoc on seals and gaskets so it shouldn't be an issue of deterioration due to fuel. The only thing I thought it could possibly be was one of the gaskets appears to have a little finger that acts as a one way valve for some function in the carb and that little finger looked deformed on the gasket I removed and was flat on the new gasket with the carb rebuild kit.

    The engine is completely stock.

    Any thoughts as to what is happening inside that little carb and what I can do about it?

    Many thanks


  2. dirtwarrior

    dirtwarrior Member

    Have you checked the air filter? That is what I would first , then check for air leaks. With engin running spray wd-40 and see if rpm raise.
  3. V 35

    V 35 Member

    That little ' flap ' on gasket is a one way vacuum valve . Those little buggers run on vacuum, as much as they do gas . Cranking the engine creates vacuum, which draw fuel through the flapper valve . During compression, the valve stays shut. The gasket itself is bolted down, never flexes . The flapper valve simply wears out [ work hardens ] . Hope that helps
  4. ChrisB

    ChrisB New Member

    Thanks for the prompt replies.
    Air filter clean.
    I guess I will buy another rebuild kit and try just replacing the gasket that is cut with the flapper valve and see if that is indeed the problem.
    Is it routine to have to replace this gasket often?
    I do not know anyone else in my area that has built one of these bikes or has this engine, and I know I am using it a lot and put a lot of miles and time on it. Maybe this is just a part that wears out (if it is indeed the problem) I know if the engine were on a weed eater, it would never in its life get the hours I put on this bike in a single season season.

    Is there another "bolt on" carb in the same form factor that is not subject to this problem?
  5. ChrisB

    ChrisB New Member

    Can anyone tell me what carburetor comes on a Tanake PF 3300? I want to buy a rebuild kit and I know I can get them much cheaper than from the tanaka dealer, but do not know what to specify.

    Many thanks!

  6. Bonefish

    Bonefish Member

  7. ChrisB

    ChrisB New Member

    Hi Bonefish,

    Thanks for the link to the carb, but what i am looking for is a link to the rebuild kit for the carb, or for the manufacturer's type/model/size of carb so I know I am ordering the correct kit.

  8. darwin

    darwin Well-Known Member

  9. darwin

    darwin Well-Known Member

    When you take that carb apart take pics if needed, damn thing is like a swiss watch to put back together. Pay special attention to the way stuff is right side up or?. Don't ask me how I know this..........................diaphragm especially.
  10. ChrisB

    ChrisB New Member

    Thanks Darwin,

    I knew the Tanaka Part number for the kit because I bought and installed a "tanaka" OEM kit before which fixed the problem for a year. However, I have not seen the picture of the parts on a grid like in your link. If I am going to be replacing these kits frequently I'll buy cheaper ones if I can.

    I hope I can use the picture in the link you sent me and find a cheaper Walbro kit that has the same parts for about $6.....unless someong knows the Walbro P/N.