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  1. #1

    Default Whats wrong with my Hunda?

    She is an early 150 HP with lots of hour on her. The first issue is she has started to mis at idle speeds this year. Typically, if it speed up a bit, it clears up at least for a while. She runs great a speed. At first I thought it was the oil around the plugs. I did an oil change and replaced the seals around the plugs and it cleared up for a while. Then both the leak and the missing came back. I replaced the seals again and the igniters. The leak is gone but the missing is still here. So I added some carb cleaner and sea foam to the water separator. Last week i went on a bug run. She ran out at 12 miles at 4K idled mostly on and off for about three hours and I ran back. No change. Here is the problem, I went to flush her on Sunday and she did not start. She sounds like she was out of fuel. Today I popped the lid and installed a pressure gauge in the line that comes off the top of the FI rail. Turn on the ign and fuel shoots out of the rail. OK, I installed the gauge to the top of the rail fuel connection. Cycle on the ign. The gauge shoots up to 50 psig and sits there. Looks good, I install the gauge in-line with the connection on the top of the rail, Cycle the ign and the gauge moves just a touch, hum. I remove the gauge, and attach a hoes to collect the fuel. Every time you cycle the ign. the rail dumps about an oz of fuel. Seems OK. Whats wrong with It? Is there a bad back-pressure is the VST? A new set of plugs and maybe a set of injectors might solve the miss, but why is the FI rail not pressurized?

    To date, the engine does not smoke, or use oil. The plugs have not appeared to be fouled. I will do a compression check after work today to see how it looks.
    Sat update
    One plug seems to show to show a bit of rust. I set the valves on Fri. Today I tried to start it, but it was unchanged.
    I checked the compression: 155, 135, 70 140. Not good!
    I rechecked 70, 100/110, 70, 140, not good and not the same.
    I rechecked with a different gauge: 100, 125, 75, 160.
    I pulled the plugs, added some sea foam and rechecked: 165, 110, 82, 190.
    I tried to start her, and not even a cough now. I pulled plugs and cleaned them (wet with sea foam),
    I got her to start first on one or two, but she clear her trough and runs fine.
    She now starts up in 1.5 sec.
    I pulled the plugs and checked the compression: 185, 130, 132, 190. Still not good.
    She seems to run OK on the hose. I did a few rounds of sea foam. The over temp alarm goes off after about 5 min on the hose.
    The bad compression reading might be related to the slow cranking, maybe but she starts right up.
    Its Sunday and she still fires right up. Another problem with my compression checks is the throttle was not opened.

    Any idea what the issue is?

  2. #2

    Default Re: Whats wrong with my Hunda?

    I cleaned the injectors today, they seem OK. # 3 was leaking when I started cleaning, now none of them seem to leak while cleaning. I have to reinstalled them to be sure.

  3. #3
    Join Date
    Apr 2018

    Default Re: Whats wrong with my Hunda?

    ,Rusty spark plug and low compression indicates water getting into the cylinder. What's the quality of the oil like?

  4. #4

    Default Re: Whats wrong with my Hunda?

    They don't look bad, but one plug looks a bit rusty, not sureClick image for larger version. 

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    I replace the injectors, the starter and the regulator. I got the parts from a buddy who has a blown engine.
    It turns over better now. She runs a bit better on the hose maybe. I have not had her on the water.
    The oil looked OK, I replaced it.
    Last edited by karlow; 10-26-2021 at 02:46 AM.

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