1986 225 hp Evinrude getting losing RPM over time.

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • 1986 225 hp Evinrude getting losing RPM over time.

    like I said a 1986 225 hp Evinrude. we don't take it out very often, but here are the WOT rpm readings (tach is a Teleflex unit that I have had on the boat for a long time). I've been in talks with PropGod in order to get a new prop, but before I do these symptoms seem puzzling.

    I have had the boat and engine since 1992, and the motor was rebuilt in 1993, not too many hours on it really, but the age, well....I am pretty sure the engine reved to 5600 with the current prop years ago, but can't be sure.

    when I reached out to PropGods recently the engine reved to 5200 at WOT, then the next time to 5000 at WOT, then on xmas only 4300 at WOT (4600 just slightly off WOT)

    I have a DVA adapter and used it today along with the Ohm meter to test some stuff. Here we go

    cylinder PSI cold
    Left Side right side
    102 102
    102 105
    106 105
    cylinder PSI warmed up
    100 95
    100 96
    105 100

    Coil Ohm Test (primary lead to ground) They appear to be just about original or at least to 1993
    Left Right
    .3 ohm .3 ohm
    .3 ohm .3 ohm
    .3 ohm .3 ohm
    (specs says the need to be .1 +/- .05, so a bit off)

    Coil Ohm Test (Secondary lead to ground)
    259.3 ohm 256.4 ohm
    262.5 ohm 269.0 ohm
    264.6 ohm 255.8 ohm
    (specs say 275 +/- 50, so that should be good)

    Coil wire ohms
    6.8 ohm .3 ohm
    .3 ohm .3 ohm
    8.3 ohm .3 ohm
    (I believe they should be zero)

    Stator tests.
    test 1 yellow wire to ground whilst engine running at 1400rpm
    left right
    15-19volts DC 35-40 volts dc
    (spec state they should be about 20volts on each side)

    as per the manual, switched yellow stator lead at junction block (where the rectifier meets the leads from stator) to see if the low volt followed to other side.
    it did not. meaning the same results
    15-19 volts 35-40 volts......if the stator was bad I would expect the low volt to follow to the new side.
    (at this point I am suspect of the rectifier, on the last outing I did see my voltmeter go to 16 volts which seems high)

    Stator test #2, brown charge wires, with test leads on the two brown wires on each side and just cranking
    Left right
    180 V+ 180 V+

    Stator Test # 3, OHM between the two brown wires for each side
    Left right
    1.03 Kohm 1.01 Kohm
    (specs say that it should be 970 Ohm +/- 15....it;s close)

    Sensor/Timer Base Tests
    test #1 Ohm (pin D to A, B, C)
    Left right
    D-A 45.2 Ohm D-A 46.3 ohm
    D-B 45.3 Ohm D-B 46.4 ohm
    D-C 45.6 Ohm D-C 46.5 ohm
    (specs say 40 +/- 10, so we're good)

    test #2 Voltage (pin D to A, B, C whilst cranking)
    Left Right
    D-A .6 v D-A .5 v
    D-B .6 v D-B .6 V
    D-C .6 v D-C .7 V
    (specs say a minimum of .3 volts whilst cranking)


    At this point I am suspect of the recitifier, but would that affect the WOT?

    note: at WOT yesterday I got 4300 rpm and GPH of 20, but if I pulled back just a bit (less air through the butterflies) I got 4600 RPM , at 35 MPH and 15 GPH....4500-4600 used to be my cruising rpm.

    I verified today that at WOT the butterflies were perpendicular to the their throats.

    What symptoms would a bad rectifier present?

  • #2
    Can we back up a bit?
    - Where do you boat? What part of the country/world?
    - How often do you boat?
    - How often do you put fuel in the boat? What size boat and what size fuel tank?
    I see you say "Whilst" so, England? Australia? New Zealand?
    Engine Sales and Service
    Ph +1 954.463.1515
    Fx +1
    954.463.4904
    Toll Free: 800.622.6747

    oparker@parkeryacht.com
    www.parkeryacht.com

    Member of the MSHS Group

    Comment


    • #3
      Originally posted by Parker Yacht View Post
      Can we back up a bit?
      - Where do you boat? What part of the country/world?
      - How often do you boat?
      - How often do you put fuel in the boat? What size boat and what size fuel tank?
      I see you say "Whilst" so, England? Australia? New Zealand?
      LOL actually just around the corner from you...in Sarasota..(oops I thought you are from the new Parker Boats I see around the corner from me near 301, but I don't think you are)

      I use whilst as I like the sound of it, have been for years. I strive for proper English, so never end a sentence with a preposition.(it's tough)

      We don't go out often. Usually a joke amongst my neighbors that we take it out for our obligatory twice a year. This year we've taken out three times so far. End of August, Thanksgiving and Xmas. I use rec gas only, for several years now, and have a racor fuel/water filter/separator. In August I put in 25 gals of fresh rec gas into the tank that had maybe 10-15 gals of rec gas from last year. For xmas I put in another 25 gals of rec gas into the same tank after burning probably 20 gals in August and Thanksgiving.

      The boat is a 21' center console, made by offshore yachts (the term is VERY loose) the hull number starts with OSY. It has two tanks, both 55 gals. the fore tank has about 10 gals (it needs to be 'polished' as it has yellow varnish that glogs up the fuel filter inlets. The aft tank is what I use the most, it too has yellow varnish crystals that clog up the fuel filter inlets, just not as bad. On xmas I would estimate that I had some where between 30-40 gals of fuel in the aft tank.

      We'll probably go out again before my daughter goes back to the coldness of Boston for college.


      Last edited by cfauvel; 12-27-2016, 11:25 AM.

      Comment


      • #4
        So, let us discuss fuel. Or Milk.
        Let us say you start off with a glass of milk that is half full, and half bad or going bad. When you add fresh milk to the glass, what do you have? A full glass of good milk or a full glass of half bad milk?
        Let us now move to fuel. You are running with fuel that is for the most part, old.
        Even Rec fuel can lose Octane and combustion properties.
        At the very least I would say a carb job is in order, and you could also run the engine off a portable tank (mixed with oil if needed) and see if you gain your RPM's back. If they come back, you might can not do the crab job.
        The lenght of time the engine sits, the age of the fuel none is good for full RPM's.
        Just a thought.
        Engine Sales and Service
        Ph +1 954.463.1515
        Fx +1
        954.463.4904
        Toll Free: 800.622.6747

        oparker@parkeryacht.com
        www.parkeryacht.com

        Member of the MSHS Group

        Comment


        • #5
          I agree with everything Ole mentioned regarding fuel and carbs. Clean the carbs; dump the fuel. Also, you checked nearly every electrical component except for the cheapest one--spark plug. Replace your plugs.

          Comment


          • #6
            Thanks everyone....all great points.

            I am going to diagnose this in stages.
            1 - replaced a fuel line from the primer bulb to fuel flow meter as I saw fuel seeping at the clamp when pumping the bulb. Noticed the primer bulb very quickly got hard from fuel pressure, where as before it took a long while. (sucking air is my guess)
            2 - replaced a very old racor fuel filter.

            on my next outing I am going to bring
            1 - an external tank of fresh REC fuel, as a test like the guy from Parker Yachts suggested. BTW I miss-read the boat mfg near me...that is actually Barker Boats.
            2 - six new plugs
            3 - six new plug wires

            I'll test the boat with just the new fuel line and fuel filter.
            If symptom is still there , then I'll move to the tank with super fresh gas, else then it was the combination of leaking fuel line and clogged fuel filter.
            if the symptom is still there, then I will replace the plugs and wires, else then it was bad gas, and will require pumping out all of the stale gas.

            If the symptom is STILL present, then another carb job....which is just replacing floats' needles and seats, gaskets and cleaning Low and Intermediate air bleeds and High jets.

            Comment


            • #7
              Originally posted by cfauvel View Post
              Thanks everyone....all great points.

              I am going to diagnose this in stages.
              1 - replaced a fuel line from the primer bulb to fuel flow meter as I saw fuel seeping at the clamp when pumping the bulb. Noticed the primer bulb very quickly got hard from fuel pressure, where as before it took a long while. (sucking air is my guess)
              2 - replaced a very old racor fuel filter.

              on my next outing I am going to bring
              1 - an external tank of fresh REC fuel, as a test like the guy from Parker Yachts suggested. BTW I miss-read the boat mfg near me...that is actually Barker Boats.
              2 - six new plugs
              3 - six new plug wires

              I'll test the boat with just the new fuel line and fuel filter.
              If symptom is still there , then I'll move to the tank with super fresh gas, else then it was the combination of leaking fuel line and clogged fuel filter.
              if the symptom is still there, then I will replace the plugs and wires, else then it was bad gas, and will require pumping out all of the stale gas.

              If the symptom is STILL present, then another carb job....which is just replacing floats' needles and seats, gaskets and cleaning Low and Intermediate air bleeds and High jets.
              This to me is THE most important part of a carb job. It is something that I believe in most cases is often done too quickly, not thoroughly enough and often looked over.
              I take about an hour a carb, we have special "picks" or "needles" we use to clean each jet, you would be amazed at the varnish that stays in that tiny hole.
              The jets need to be REMOVED, not just have air blown through them.

              Engine Sales and Service
              Ph +1 954.463.1515
              Fx +1
              954.463.4904
              Toll Free: 800.622.6747

              oparker@parkeryacht.com
              www.parkeryacht.com

              Member of the MSHS Group

              Comment


              • #8
                Originally posted by Parker Yacht View Post
                This to me is THE most important part of a carb job. It is something that I believe in most cases is often done too quickly, not thoroughly enough and often looked over.
                I take about an hour a carb, we have special "picks" or "needles" we use to clean each jet, you would be amazed at the varnish that stays in that tiny hole.
                The jets need to be REMOVED, not just have air blown through them.
                I completely agree. One of the former mechanics in my shop would argue with me about this constantly. He would use the ultrasonic cleaner or carb dip but not remove and inspect each jet. It used to drive me NUTS. I had to show him that even after the chemical bath and ultrasonic, there was still scale in portions of bowl and the jets were not 100% open.

                I believe this often overlooked step is the culprit to untold thousands of grenaded cylinders in multi-carb reciprocating engines. It only takes one jet to be fouled up to produce a lean condition.

                Comment


                • #9
                  Originally posted by finsleft258 View Post

                  I completely agree. One of the former mechanics in my shop would argue with me about this constantly. He would use the ultrasonic cleaner or carb dip but not remove and inspect each jet. It used to drive me NUTS. I had to show him that even after the chemical bath and ultrasonic, there was still scale in portions of bowl and the jets were not 100% open.

                  I believe this often overlooked step is the culprit to untold thousands of grenaded cylinders in multi-carb reciprocating engines. It only takes one jet to be fouled up to produce a lean condition.
                  I third that point....better to be running too rich, than too lean. Clogged High Speed jets would be a lean condition

                  Comment


                  • #10
                    Cleaning carbs is like boat "restorations", it means different things to different people.
                    Spraying "cleaners" in carbs is not a carb cleaning IMO.
                    Ultrasonic cleaners are nice, but they do not do a "thorough" job in carb cleaning, IMO.
                    Engine Sales and Service
                    Ph +1 954.463.1515
                    Fx +1
                    954.463.4904
                    Toll Free: 800.622.6747

                    oparker@parkeryacht.com
                    www.parkeryacht.com

                    Member of the MSHS Group

                    Comment


                    • #11
                      Originally posted by Parker Yacht View Post
                      Cleaning carbs is like boat "restorations", it means different things to different people.
                      Spraying "cleaners" in carbs is not a carb cleaning IMO.
                      Ultrasonic cleaners are nice, but they do not do a "thorough" job in carb cleaning, IMO.
                      Yep. I purchased the ultrasonic cleaner after listening to a jet ski mechanic in my area rant and rave about how much it cut down carb cleaning time. Total BS. One of the ten worst purchases for the shop. It does kick ass for cleaning cylinder heads and parts not related to the fuel system. For VSTs and carbs, it must be an intimate, physical deal. Gotta caress those curves and edges to get them to perform.

                      Comment


                      • #12
                        Originally posted by finsleft258 View Post

                        Yep. I purchased the ultrasonic cleaner after listening to a jet ski mechanic in my area rant and rave about how much it cut down carb cleaning time. Total BS. One of the ten worst purchases for the shop. It does kick ass for cleaning cylinder heads and parts not related to the fuel system. For VSTs and carbs, it must be an intimate, physical deal. Gotta caress those curves and edges to get them to perform.
                        Unfortunately, most people don't understand 4-5 hours in cleaning the carbs on their 2004 40 hp with fuel that is three years old.
                        Engine Sales and Service
                        Ph +1 954.463.1515
                        Fx +1
                        954.463.4904
                        Toll Free: 800.622.6747

                        oparker@parkeryacht.com
                        www.parkeryacht.com

                        Member of the MSHS Group

                        Comment


                        • #13
                          Or fuel lines, or filters, or...

                          Comment


                          • #14
                            Originally posted by finsleft258 View Post
                            Or fuel lines, or filters, or...
                            yeah probably my issue and mistake

                            Comment


                            • #15
                              UPDATE: no update yet, but rest assured that I will respond with test updates as they are performed...right now working on a soft spot on the casting deck.

                              Comment

                              Working...
                              X