outboard underperforming

bcarltonbcarlton Posts: 11 Greenhorn
I have a yamaha 225 hpdi that is underperforming badly.
It tops out at 4800 rpms and will only push my 22 pathy about 40. Granted it does have a tower, trolling motor and three batteries. The main thing that concerns me is the rpm's. Any of you guys have any insight?

Replies

  • SwizzleSwizzle Posts: 534 Officer
    Has it ever performed better than this?
  • CaptTaterCaptTater Posts: 20,096 AG
    Right it could be as easy as overpropped or it could be broken.
    I did not read the story but if you take tax payers money maybe you should be held to some standards.-Cyclist
    when we say the same thing about welfare recipients, you cry like a wounded buffalo Sopchoppy
    It's their money, they spend it how they like. Truth and honesty have nothing to do with it. - Mr Jr
    "“A radical is one who advocates sweeping changes in the existing laws and methods of government.” "
  • DRIFTER_016DRIFTER_016 Posts: 144 Officer
    As Swizzle says did it perform better at one point?
    Has it always been like this?
    If it has you are badly over propped.
    Max RPM's should be between 5,000 and 6,000.
    You want to be closer to the 6000 range.
    You gain about 200 RPM for every one inch drop in pitch on your prop.
    To get up into the best part of the power band you need to drop 5 inches.

    If the loss of performance happened over time it could be that the flotation foam in your boat could be saturated with water.
    If this is the case the bast way to determine is to head for your nearest weigh scales and check the weight of the boat to see if it's over.
    On a boat that size the foam could be holding 1000 pounds or more of water.

    Lets start with what is the current prop on your boat (diameter and pitch)?
    What is the weight of your boat loaded for fishing?
    We can determine if the prop is correct this way.

    So give us a little more info and we'll see if we can fix your performance issue. :wink
  • Pat LPat L Posts: 440 Officer
    If the motor has truly lost RPM the first thing is to make sure it has good compression, then try a set a spark plugs.
  • capeanglercapeangler Posts: 586 Officer
    Ps supply more info. You have everyone guessing.

    1. How long have you owned the boat/motor combo? What year boat/motor?
    2. What were the performance numbers when you first purchased/used the boat (Hopefully much better)?
    3. If you were in the 6000 WOT Range (Where you should be); did it drop to 4,800 overnight; or over time?
    4. Did you make any changes to the prop or have any work done to the motor when this occurred?

    Ps. supply more info and members can better point you in the right direction, if not totally help you trouble shoot the problem. Shooting from the hip; it's not the weight of your gear; you either have the wrong prop or you have a motor issue. Hope it's the prop. With regards to the motor; it could be a long laundry list of things....................
  • bcarltonbcarlton Posts: 11 Greenhorn
    The prop is a 14.5 inches with a 23 pitch (23-m i believe). I did some research and found some similar cases where the vst filter was the problem. It was about due for a service anyway so hopefully this cures the problem.
  • CaptTaterCaptTater Posts: 20,096 AG
    Yamaha says the 200HPDI pushes the 2200V at nearly 60MPH with a 21"
    Does it sputter? A VST being clogged will not just run weak it will mis and jump and sputter.
    Sounds to me like you are down at least 1 cylinder and maybe 2.

    Hopefully plugs and filter cleans will fix it up.

    I would get a compression check.
    Fuel pressure check at the VST (UNDER A LOAD)
    New plugs
    test spark plug boots
    Fuel injector cleaner (not removed, left in at first).
    I did not read the story but if you take tax payers money maybe you should be held to some standards.-Cyclist
    when we say the same thing about welfare recipients, you cry like a wounded buffalo Sopchoppy
    It's their money, they spend it how they like. Truth and honesty have nothing to do with it. - Mr Jr
    "“A radical is one who advocates sweeping changes in the existing laws and methods of government.” "
  • bcarltonbcarlton Posts: 11 Greenhorn
    Yea tater those stats are the ones that scared me. I didn't even think of the cylinders though. Safe to say this one is out of my league mechanically. Thanks for everyone's help I will post when I get word from the mechanic just for fun.
  • CaptTaterCaptTater Posts: 20,096 AG
    down cylinders are common in those HPDIs.. frequently injector or plug boots or fouled plugs. I had that a lot with my 300s until I switched to Pennzoil XLF and Starbrite from yamalube crap.
    I did not read the story but if you take tax payers money maybe you should be held to some standards.-Cyclist
    when we say the same thing about welfare recipients, you cry like a wounded buffalo Sopchoppy
    It's their money, they spend it how they like. Truth and honesty have nothing to do with it. - Mr Jr
    "“A radical is one who advocates sweeping changes in the existing laws and methods of government.” "
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