Buzzing noise/alarm at 5k rpm

bgmartin2bgmartin2 Posts: 24 Greenhorn
Hello,

Two weeks ago while out my 88 Johnson 225 made a buzzing noise when the rpm hit 5k. Anything under that was ok but right at 5k and above the noise would come on.

Reading online I saw some say the impeller can cause this but the people asking say they boat makes the noise when it starts.

Are there any other possibilities of this noise? My oil reservoir is about 1/4 full so maybe it just doesn't like to be that low? I will fill it and run with ears on see if it makes it again.

Thanks for any information.

bgmartin

Replies

  • reel stamasreel stamas Posts: 6,153 Admiral
    I think you're on the right track, but IMO you should NOT run it on the ears (w/no load) anywhere near 5K RPMs... OB Engines (esp. 2S) are not designed to be run @ high RPM unless under load (maybe a mechanic can explain this better)...
    That said, my guess is the same as yours- either 1) Low Oil Reserve Warning Buzzer (the engine consumes more oil @ high RPMs) or 2) possibly Water Pump/Impeller/Overheating issue...
    There should be NO Commercial Fishing for any fish species considered 'Over-fished' , 'Undergoing Overfishing' or Subject to Recreational Seasons, Limits, or Closures... Game Fish Status IS the Answer !!!
  • Pat LPat L Posts: 440 Officer
    Correct dont run it that high on a hose or in neutral and chances are it wouldnt simulate the issue you have anyway. That motor also has a high fuel vacuum alarm, so if there is a fuel system restriction it will set the alarm off. The reason it does it at 5000rpm is that is when the engine is starting to pull the most amount of fuel from the boat, revving it on a hose is not going to require that much fuel as when under a load and wont set the alarm off. If the alarm goes away as soon as you back of the throttle chances are thats what it is.
  • reel stamasreel stamas Posts: 6,153 Admiral
    If it is a fuel restriction alarm, I'd look at the anti-siphon valve in the tank 1st (as they are notorious for causing that problem)
    There should be NO Commercial Fishing for any fish species considered 'Over-fished' , 'Undergoing Overfishing' or Subject to Recreational Seasons, Limits, or Closures... Game Fish Status IS the Answer !!!
  • bgmartin2bgmartin2 Posts: 24 Greenhorn
    Thanks for all the replies...what does the anti-siphon valve look like and where would it be located? I only have a 10" port hole for access to the gas tank.

    This tank is brand new, just built a year ago, so would that valve act up this quick?
  • reel stamasreel stamas Posts: 6,153 Admiral
    The anti-siphon valve is a 1 way ball/spring valve inside the fitting that screws into the top of the tank. ~30yrs ago when I dealt w/multiple boats (many w/problems) on a regular basis I saw them fail in <1 yr. I don't know if the newer ones are any more reliable (or if ethanol is causing more problems) ?
    When I bought my NEW tank I had to reuse the fittings from my old tank, so new tank doesn't always = new fittings...
    Now that I think about it, a bad fuel hose/bulb could also cause fuel starvation. My main point was to look at the 'cheap' fixes before you replace the fuel pump...
    There should be NO Commercial Fishing for any fish species considered 'Over-fished' , 'Undergoing Overfishing' or Subject to Recreational Seasons, Limits, or Closures... Game Fish Status IS the Answer !!!
  • bgmartin2bgmartin2 Posts: 24 Greenhorn
    Thanks again.

    I am relatively new to boating and the in and out of repair/maintenance for them. (computers now are no problem :) ).

    One other thing I just thought of that I was curious about is the gas gauge. I just installed a new one recently and when I turn the ignition to the on position the indicator only goes up to the 1/4 mark even though I know there is more gas in there.

    When we are out on the water and running the gauge goes up and seems to start registering correctly.

    Is that normal?

    Thanks again.
  • SCFD rtrd.SCFD rtrd. Posts: 1,373 Officer
    It's not unusual for the fuel indicator to rise when running. When you are running, the bow of the boat lifts and forces the fuel in the tank toward the rear of the tank, thus lifting the float on the fuel sending unit. The fuel gauge can fluctuate as much as 1/4 tank in some boats. Always make a habit of checking your fuel gauge when the boat is sitting still. Check the wiring connections at the fuel sending unit on top of the tank. Corroded wiring or connections can give inaccurate fuel readings. Your oil reservoir also has a float similar to the gas tank. At 1/4 tank and on a plane it might register low oil and trigger an alarm.

    Alarms can mean a number of things. Overheating, fuel restriction, low oil, water in fuel and others. The first thing to do would be to fill the oil reservoir and see if the problem goes away. Then remove the anti-siphon valve and see if that is the problem. You don't need the anti-siphon valve to operate, it's just required to be installed on new boats. Then replace the fuel filters which may cause a fuel restriction. If the fuel lines are old, replace them.
  • bgmartin2bgmartin2 Posts: 24 Greenhorn
    Took her in for troubleshooting, will let everyone know what the verdict is when I find out.
  • bgmartin2bgmartin2 Posts: 24 Greenhorn
    Well, new impeller and water pump installed as well as thermostats because the mechanic said there weren't any installed??!!!?? Don't know how that happened or is possible but he put some in.

    Thanks again for everyone's help before.
  • latitudeajustmentlatitudeajustment Posts: 2,001 Captain
    bgmartin2 wrote: »
    Well, new impeller and water pump installed as well as thermostats because the mechanic said there weren't any installed??!!!?? Don't know how that happened or is possible but he put some in.

    Thanks again for everyone's help before.

    What the ????? You have got to be kidding! How could you even run that, was there a pee stream??
  • snookaffinitysnookaffinity Naples, FLPosts: 1,035 Officer
    I think he was referring to the thermostats only.
    "It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt." - Mark Twain
Sign In or Register to comment.