Harbor Freight Carb flooding engine after turning off engine.

Discussion in '2-Stroke Engines' started by Bonefish, Jun 25, 2010.

  1. Bonefish

    Bonefish Member

    I've got a Harbor Freight 1.5 Hp 2 stoke Water pump engine on my bike, It is almost identical to the 1.5 HP Gas Auger they sell. The engine runs great and strong, but when I hit the kill switch and turn off the engine, it seems like the throttle is stuck on and the carb. is flooding the engine. So when I go and start it after sitting for a while it is flooded, and takes a lot of pulls to get it to start. The gas is coming out of the port on the outside where the air filter is at and leaking on the ground as well after engine is off. I checked and it does not look like any linkages/cables are stuck. Not sure what the problem is. Any Ideas?


  2. G-Superior

    G-Superior Member


    Clean the small needle and seat inside the fuel bowl and it should go away:D
    It happens to small engines all the time and i have done 100s
    Last one i did was my little 2 stroke generator, it is a very simple job!
    And just to make sure it does not happen again use a inline fuel filter.:idea:
    Good Luck and if you habe any more problems just ask.
  3. Bonefish

    Bonefish Member


    The engine is brand new. I do not even have a tank of gas run thru it yet. There is a fuel filter located at the bottom of the fuel line, that is in the bottom of the gas tank.

    I do not know that much about carbs. There is a white piece of plastic. It looks like a diaphram that is located on the outside of the carb port between the air filter and air breathing port. It is a shoddy piece of engineering they did. Do I need this piece or will it be safe/alright to run without it? Are there any other possibilities?

  4. G-Superior

    G-Superior Member

    can you take a picture and show us because i never seen that engine before in my life plus there are 30000000 diferent carbs out there
  5. Bonefish

    Bonefish Member

    Here are some picts.

    Check attachments.

    The white plastic piece is the piece that goes on the outside of the carb inbetween the foam air filter and the air intake port. I would love to be able to leave this off if i could and it wouldn't hurt the eninge.

    If you look at the picts, the one with the close up, that is where the gas leaks out of the carb after the engine is shut off.

    If anyone has any ideas on how to alleviate this problem, please let me know. It is a beast of burden pulling this thing about 15 times to get it to start because it gets flooded after sitting for a while. If I turn it off, and then pull start it, it will crank right up. It is only after sitting for about 10 minutes, that it gets flooded, and then will take about 15 pulls to get it to start to fire up. Any Ideas?


    Attached Files:

  6. Nuttsy

    Nuttsy Member

    My HF pump motor came with the fuel tank mounted BELOW the engine. It has a Walbro WYK diaphragm carb. with dual fuel lines and a primer pump. There is no fuel bowl or float. Is that the setup you ORIGINALLY had? Or maybe you have a different carb. I'm only seeing one fuel line on your pics and it goes UP to a remote tank out of the picture somewhere. The fuel is probably free flowing (gravity) when the engine is off and you may need to put a shut-off in that line. Or maybe the fuel line is connected to the wrong nipple (if you have the above setup).

    Unless I'm missing something in the pics. But just for grins, try clamping (pinching) off the fuel line when you shut it off next time and wait a while and THEN try to restart it (after removing the clamp).

    Also, lose the air filter and get an aftermarket K&N type. About $15 and the engine breathes much better. If you do get the air filter, make sure you get the velocity stack WITH the choke lever.
  7. Bonefish

    Bonefish Member

    Everything is original right from Harbor Freight, no mods made yet except my engine did have the tank below it as well, but I removed it and put a 1 gallon tank on the back cargo rack that has dual fuel lines that run to it.(one line is yellow, the other black). It does have a primer bulb on the bottom of carb as well. I did take the gas tank off of the rack and positioned it on the ground, but the carb still leaked after the bike was shut off. So i'm not sure if it is because of gravity then, because the tank was then below the engine.

    It is a pain in the ***, pulling this starter cord 15 times everytime to get the engine to start after sitting.

    It cranks right up though on first pull though, if I shut it off, and then start it right back up.

    It is only after it has been sitting for about 10 min. or longer it gets flooded.




    Thanks for showing that pict. diagram of you putting the R/S eh035 clutch on this engine. My honda gx31 clutch fit on it as well.

    Super thanks,

    I bought the engine without knowing it didn't have a clutch.

    Thanks again,

    Attached Files:

  8. GearNut

    GearNut Active Member

    Mount the gas tank below the carburetor and it will stop the flooding problem. Those diaphragm carburetors are not designed to have the gas tank above them. A fuel valve on the inlet hose may help, but unless you put valves on both hoses, there is no guarantee that fuel will not flow, gravity fed, back thorough the return hose and you flooding problem will still haunt you. FWIW, you do not need 2 hoses going to it anyways.
    You can have one valve controlled hose going to a tee, the tee mounted as close to the carb as you can reasonably get it, and connect the 2 carburetor hoses and the one fuel tank hose to the tee.
  9. G-Superior

    G-Superior Member

    I think even being a diaphragm carb. the tank can be gravity feed. thats why it has a small needle inside to control the fuel flow
    the diaphragm works just like a pump them the needle is there to make sure it does not flood
    If you not very mechanical person take it to a mower shop and they will clean you carb no problems at all at a resonable price. If that does not work then I would just get a new carb if it was in the warranty or a good 2nd and one.
  10. Bonefish

    Bonefish Member

    It is kinda funny, yesterday, I was trying to crank it and someone said," that doesn't sound good" it was a mechanic. He gave me some cleaner spray, and we sprayed some of it up both ports on the carb with the needlenozzle to try and blast out any trash/debris that might have been in there.

    Last night the carb didn't leak, and it cranked up this morning on the 2nd pull. Not sure if it is fixed, but this engine screams with no load on it, but then bogs down after it is floored for a second. Never did that before.

    Right now, I have no load on it because I've got to fabricate a new chain tensioner wheel for the drive chain.

    Thanks for the advice and tips. I really do not know of a way I can mount the tank below the carb, because my pedals will hit the tank when I pedal then. The place where I have it is where I hope to keep it. I might have to get the fuel shut off valves if it comes back/persists.

    Many thanks,
  11. Bonefish

    Bonefish Member

    Does anyone know for a fact if this carb on a HF 1.5 HP 52cc Water Pump Engine can have the fuel tank mounted above it, or will gravity force it to flood?

    We sprayed some carb cleaner up both ports on the carb and it fixed it for about a week and I had no problems with the tank mounted above the carb, and no leaking problems when i shut off engine, then all of a sudden.....................................

    Huge fuel leaking problem coming out of carb/air filter while the engine was running causing the engine to flood and shut down. It seems like I can not isolate one variable to diagnose what is wrong with it. It has no consistency.

    I went to find some fuel shut off valves, but had no luck. Bought a pinch clamp, and clamp both hoses after I shut the engine off. But the engine floods now while it is running.

    It seems like, If i pull on the recoil/starter puller very slowly, and pull air into the pison chamber before I start it, is the only way I can get it to start after flooding.

    Also after I get the engine started with the clamp on the hoses, but then need to take the clamp off so the engine gets fuel, it causes the engine to shut down/flood. Im not sure though if it is just because it is causing a short burst of fuel to blast up into the carb though after clamp is removed.

    Any ideas?

    Thanks and Happy 4th.
  12. G-Superior

    G-Superior Member

    like i said before just take the carb apart and clean the needle, jets and everything else that there is and put a in line fuel filter.
    it happened to my yesterday on my midimoto which has the same engine as your bike and the same carb.
    Good luck
  13. Bonefish

    Bonefish Member

    This thing is a basketcase. There is no consistency with this engine. You can not isolate one variable and diagnose the problem. The carb has been taken off and cleaned. The fuel tank has been mounted to a position that is below the carb.

    Sometimes is runs, and then it will not start for hours.

    It seems like this thing has brief moments of joyful bliss, followed by agonizing hours of tedious tinkering.
  14. Bonefish

    Bonefish Member

    Got it started after several hours of tinkering. Then it started to Idle/Rev. really high, and when I applied throttle it sounds strong until it gets to about 3/4 throttle then bogs down and will not accelerate any further.

    Took it for a spin to find out if i could fine tune it with the brass/spring idle adjustment knob on the bottom of carb. and got the idle down, but it now bogs down even sooner before 3/4 throttle, and wouldn't even climb a hill.

    Now it is sitting, and will not start. The only way I can get it to start is if i turn the idle screw all the way, and then pull start it. It cranks/fires up but dies right away. Even after giving it gas to help it from stalling out. Then I have to turn the idle screw the other way, and then crank it up to get it to fire up again, but then it too again dies. It will not start and stay running now.

    Very inconsistent.

    If anyone knows any steps I can take to isolate some variables of what to do/what the problem is. I would appreciate it.

    I tinker with it, and do one thing, then check how it responds to what i did, but it seems like I get different responses doing the exact same things.

    Any Ideas?


    Stuck roadside.
  15. G-Superior

    G-Superior Member

    dont give up

    If you are really bored of that carb. just get a new one and hope it dosent give up on you, I bet they are not that expensive:icon_cry:
    Sometimes there can be a problem that happened back in the factory and you know how chinese factorys are!" is it good? goes on the line! Is it not so good? goes in the line anyway! Is it junk? I really dont care!" thats how i think about then, its all about lucik with chinese stuff:veryangry:
    Good luck
  16. Bonefish

    Bonefish Member

    Thanks for your help. I think what happened to the carb was this............

    I was at a shop that is called the Recyclery, that gets donated bicycles. You can go in there and build a bicycle, or repair your bicycle from parts that are off of scrap/donated bikes. I had the engine setting in the frame but not mounted and a volunteer, bumped my bike and down went the engine with heavy *** staton gearbox attached to it on a concrete floor. It hit hard. It might have knocked the carb out of wack.

    Anyhow,It is now running. I now have the gas tank mounted under the carb, but it is on the rear rack stay. It looks like something sanford and son put together, but It works for now. I also took off the carb linkages and lubricated them and made some adjustements, and tweeked the idle set screw.

    She runs now...............................................

    Later on.................... Who knows.

    Thanks again,

    I learned alot anyway if nothing else.
  17. motor_head

    motor_head Member

    do you have the line to the primer gravity fed if so that might be the problem there is no needle to regulate the flow off that line so i think when it gravity fed it will just flow all the time
    take that line off the tank and see if it helps
  18. Nuttsy

    Nuttsy Member

    "I was at a shop that is called the Recyclery, that gets donated bicycles. You can go in there and build a bicycle, or repair your bicycle from parts that are off of scrap/donated bikes. I had the engine setting in the frame but not mounted and a volunteer, bumped my bike and down went the engine with heavy *** staton gearbox attached to it on a concrete floor. It hit hard. It might have knocked the carb out of wack. "

    "And now, the rest of the story..."

    The late, great, Paul Harvey

    Ya coulda told us that to start off with.

    Dude...sounds like it's a new motor/pump. Put it back together and take it back and get a replacement.
  19. Bonefish

    Bonefish Member

    Not sure if the drop/fall though hurt the carb.................................

    Isolated some variables and I now have some consistency. I mounted the 1 gallon tank on the rear rack stay below the carb, and I no longer have flooding problems. I'm not sure, but almost 90% sure that you can not have the tank above the carb. on this engine.

    What I have now:

    To get the engine to start, I have to adjust the brass/spring/idle screw to the far left. However when I run the bike at this setting, it bogs down at about 1/2 throttle. Now to get the engine to run good and strong, I have to adjust the brass/spring/idle screw to the right and tighten it. The motor runs very strong, doesn't bog down, and screams. It is very FASTTTTTTTTTTTTT, but when I go and shut it down, and then restart it, it will not start.

    The only way I can get the engine to restart again is if I turn the brass/spring/idle screw to the left again, restart it, and then after it starts, I have to adjust the brass/spring/idle screw again to the right to get the engine to run properly.

    Any Ideas?

  20. GearNut

    GearNut Active Member

    The low speed fuel/ air mixture needs tuning.
    If you have to increase (turn in) the idle speed screw to get it to start, the mixture is too rich as increasing the idle speed adds more air during starting.
    If you have to decrease the idle speed to get it to start, then the opposite is true.
    It is too lean.
    I had one of those carbs on my Go-Ped (same engine) and I eventually replaced it with a better one that was waaay easier to tune and actually kept it's tune.