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-   -   B&S 16.5HP OHV motor runs ruff at full throttle/under a load. (https://www.askmehelpdesk.com/showthread.php?t=234662)

  • Jul 7, 2008, 06:32 AM
    NatiVe TouCh
    B&S 16.5HP OHV motor runs ruff at full throttle/under a load.
    B&S - 16.5HP OHV motor
    Model: 31C707
    Type: 0154E1
    Code: 040408ZD

    Question, my 16.5HP motor runs fine when idling and at half throttle but, when I put it in full throttle and let the deck down it runs really ruff (under a load). So much so that I have to actually stop and let the mower gain some power while mowing sometimes. I am only mowing like 2"-4" tall grass on the medium deck level and it acts like it is falling on its face. I have replaced the spark plug, fuel filter, adjusted the valves and put a new needle in the carburetor. I even took the deck out from under the mower and checked that the pulley bearings were spinning freely and everything seems OK, the deck seems to be fine but, still runs ruff under a load. I was thinking it might be a leak in the head gasket? It sounds very load (exhaust pipe dumps into the muffler located in front) and I am NOT getting any black or white smoke just runs ruff at full throttle and even worse under a load. Any thoughts/opinions would be greatly appreciated, thank you again! :confused:
  • Jul 7, 2008, 03:07 PM
    MOWERMAN2468
    Inside the throat of the carb there are some very tiny holes, these can also be reached by removing the welch plug on the outside of the carb body. Did you clean these holes out? I would reclean the entire carb.

    If you think it is a head gasket, they are not very expensive. Just replace the gasket, or take it to a shop and let them do a leak down test on the engine.
  • Jul 7, 2008, 07:22 PM
    NatiVe TouCh
    Quote:
    Originally Posted by MOWERMAN2468
    inside the throat of the carb there are some very tiny holes, these can also be reached by removing the welch plug on the outside of the carb body. did you clean these holes out? I would reclean the entire carb.

    If you think it is a head gasket, they are not very expensive. Just replace the gasket, or take it to a shop and let them do a leak down test on the engine.
    I don't think it's the head gasket, just curious if a bad head gasket would cause this symptom I am experiencing. I will re-clean the carb again but, last time I took it apart I blew it all out with my air compressor. Thanks for the advice! :)
  • Jul 13, 2008, 08:10 AM
    NatiVe TouCh
    Quote:
    Originally Posted by NatiVe TouCh
    I don't think it's the head gasket, just curious if a bad head gasket would cause this symptom I am experiencing. I will re-clean the carb again but, last time I took it apart I blew it all out with my air compressor. Thanks for the advice!!:)
    OK, took apart the carb again and cleaned it out real good. Must have been to good I guess, the motor ran worse then it did, kicking out black smoke and then would die or barely idle then die. If I gave it any gas at all it would kick the black smoke then want to die. I tried starting it a few times like this and now after it died this last time I have no power to the starter and the ignition switch won't even turn the starter over. I have charged the battery and it is 100% charged and still no power from the ignition switch, when I turn the key over I can here it activating the plug at the bottom of the carb (clicking sound when the key goes on/off) that has the white and black wires going to it. Is this part possibly bad or it is something with my ignition switch or starter? Time for me to pull out my test light and start seeing how far I get power down the line on this thing. Any advices/help would be greatly appreciated, thanks again!
  • Jul 13, 2008, 02:03 PM
    NatiVe TouCh
    Quote:
    Originally Posted by NatiVe TouCh
    B&S - 16.5HP OHV motor
    Model: 31C707
    Type: 0154E1
    Code: 040408ZD

    Question, my 16.5HP motor runs fine when idling and at half throttle but, when I put it in full throttle and let the deck down it runs really ruff (under a load). So much so that I have to actually stop and let the mower gain some power while mowing sometimes. I am only mowing like 2"-4" tall grass on the medium deck level and it acts like it is falling on its face. I have replaced the spark plug, fuel filter, adjusted the valves and put a new needle in the carburetor. I even took the deck out from under the mower and checked that the pulley bearings were spinning freely and everything seems OK, the deck seems to be fine but, still runs ruff under a load. I was thinking it might be a leak in the head gasket? It sounds very load (exhaust pipe dumps into the muffler located in front) and I am NOT getting any black or white smoke just runs ruff at full throttle and even worse under a load. Any thoughts/opinions would be greatly appreciated, thank you again! :confused:
    OK, replaced the starter solenoid and it is starting again, also cleaned out the carb real good and still runs ruff at full throttle. Hmmm. I think I am seeing some oil come from the bottom gasket located near the bottom of the block near the oil drain plug. That's not good. Anyone have any idea, I am at my wits end here.

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