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getting more speed out of 90 hp johnson

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  • getting more speed out of 90 hp johnson

    i just got the deal of a lifetime yesterday. i bought a 1990 16 ft. sunbird fish/ski with a 90 hp johnson outboard. it just had the carbs redone and a frsh tune up. it had sat for over a year and a half so i had to drain all of the gas out of it and put a new battery in it. after that was done it fired right up. i took it down to the waterway and had a blaste on it. it ran a solid 40-45mph and gets out the hole pretty quick..what i would like to know is if a jack plate is going to give more speed and a quicker hole shot. it has a stainless prop on it and dont know the pitch. could someone tell me how to find that out.
    also it is not spitting the water out of the motor like i thought it is supposed to. does this particular engine do that. it is a 2 stroke and has 2 separate tanks for the oil and gas and mixes automatically..any suggestions to make this thing run top notch please let me know.
    i wasnt even going to buy another boat this year but this was too good of a deal to pass up..thanks


  • #2
    Re: getting more speed out of 90 hp johnson

    What year/model 90hp?

    If it is new to you, and has been sitting, replace the impeller.

    Look on the inner lip of the prop hub for a stamped number. What was you WOT RPMS? Post the pitch when you find it.
    Chris

    Top Secret Files:

    http://forums.iboats.com/showthread.php?t=299680

    Comment



    • #3
      Re: getting more speed out of 90 hp johnson

      My 90 does 40, that's pretty good for a 90
      sigpicSignature- If you have fuel and spark- Have you checked compression?

      Comment



      • #4
        Re: getting more speed out of 90 hp johnson

        Just find some down hill water and youll b fine. Seriously tho, make sure you have a good tell tale before beating on that motor. If you have the vro, you should have a tell tale.

        Comment



        • #5
          Re: getting more speed out of 90 hp johnson

          Just how much more speed are you expecting? 40-45mph out of that 90 is pretty good if you want much beyond that then you might be looking at breaking out the wallet and your deal of a lifetime would become the deal that was.
          1985 Baretta Vanguard 16ft & 1984 Evinrude 75hp O/B

          ****Running your motor without water is like peeing into the wind, it's a stupid impulse that is going to be a mess later****

          Comment



          • #6
            Re: getting more speed out of 90 hp johnson

            What they all said !!!!
            The best way to get more out of your 90HP is to make sure you are set up correctly (motor height, WOT RPM, loading of the people and gear on board and making sure it is tuned up properly)
            Beyond that the best way to get more from your 90 HP is to trade it in for a 115 HP or above
            sigpicMarada 2100 Executive Series, 5 Litre V8 with Mercruiser Alpha 1 outdrive. 2007 K-Z Spree 260 RBH, all = a whole lot of family fun !!!!

            Comment



            • #7
              Re: getting more speed out of 90 hp johnson

              Originally posted by watergecko View Post
              Just find some down hill water and youll b fine. Seriously tho, make sure you have a good tell tale before beating on that motor. If you have the vro, you should have a tell tale.
              it is the VRO V4 engine..as far as how many people and equipment on board, it was just me and my lady and a cooler. as far as the rpms, the tach isnt working. i have to look and see if i can get that going. i have only taken it out the one time because i just got the boat monday.
              one thing i am also very concerned about is if there should be water streaming out of the engine while it is running. i always thought engines the mix the oil and gas should have that. this is the first time i have ever owned a outboard but not my first boat.
              also should this boat burn alot of gas? i will check the pitch on the prop and post it later..thank you for everyones replies..i love this site
              oh yeah and it is a 1990 johnson vro v4

              Comment



              • #8
                Re: getting more speed out of 90 hp johnson

                First fix the tachometer.

                Yes there should be water coming from the pee hole. And yes the V4s can burn an obscene amount of fuel 'specially when yer gettin on em.

                I too would recommend starting with a fresh impeller, but then again if you're not getting high temp alarms, providing your alarm(s) work. It's entirely possible there's an obstruction in the tattle-tail hose or fitting. Might could be a worm or a bug holed up in there. It happens.

                Ya y'oughta be able to find a # stamped/etched into the prop somewhere. Can you post pics?

                Might surprise some as to just how much performance you can get outa a 90 when it's rebuilt, balanced, and/or dialed in right. This slightly modded '86 has pushed my boat to just under 55mph @ about 6200rpm.

                Just 'member to use good oil & gas. I run Sunoco premium & Quicksilver synthetic in mine.

                Good luck on your quest!
                1981 Baja 15SS_1983 Johnson 140_62.9 mph
                1981 Glastron/Carlson C500 metric series_Modified 1978 Evinrude 140_Project
                1971 Glastron V153_1986 Evinrude 90_54.8 mph_Rebuilt then unceremoniously wrecked
                Walk Tall And Carry A Big Bilge Pump

                Comment



                • #9
                  Re: getting more speed out of 90 hp johnson

                  If you don't "know" the motor then give it a basic health check, change the impeller and the lower unit oil.

                  Oh and I would suggest getting an OEM manual.
                  sigpicMarada 2100 Executive Series, 5 Litre V8 with Mercruiser Alpha 1 outdrive. 2007 K-Z Spree 260 RBH, all = a whole lot of family fun !!!!

                  Comment



                  • #10
                    Re: getting more speed out of 90 hp johnson

                    Originally posted by kenmyfam View Post
                    If you don't "know" the motor then give it a basic health check, change the impeller and the lower unit oil.

                    Oh and I would suggest getting an OEM manual.
                    checked with the machanic and the lower unit oil and impeller have both been changed. it was used once since all of that was done. i personally know the last owner and know its history. the mechanic is certified and works at a reputable shop. my concern is the water peeing out of the engine. what should i check. i am a tattoo artist and work crazy hours because it is coming into the busy season so i dont have the time i would like to have to mess with this thing. i have been cleaning and getting everything tightened every night for the time i have left in a day..
                    where will i get this manual from?

                    Comment



                    • #11
                      Re: getting more speed out of 90 hp johnson

                      will it hurt the engine to change from the reg 2 cycle oil to 2 cycle synthetic. i always heard that in a car u should use it from the first oil change but dont switch to it. will the premium gas make the engine run better? also the tach isnt working where does that hook to on the engine? i need to get that working. it worked when i first took it out..any suggestions will help and thanks for all of ur responses

                      Comment



                      • #12
                        Re: getting more speed out of 90 hp johnson

                        Is this GPS speed or wishometer speed??? Cause I can't think of much more you could want out of it.. Thats moving right along...
                        I guess you could alway hang more engine off the back..

                        ALL 2 stroke outboards drink the fuel.. They like it.. ALOT
                        sigpic

                        87 Four Winns 170 Horizon 4.3 OMC COBRA"Only Child"
                        only thing GM I own.. Of course it's the only one that gives trouble..
                        2004 Ford STX 4x4.
                        2011 Candy Apple Ford Mustang GT
                        Hope all you want.. It won't get it fixed..

                        Comment



                        • #13
                          Re: getting more speed out of 90 hp johnson

                          As long as the two cycle oil has TC-W3 printed somewhere on the bottle you will be okay. Your outboard has a tell tale on the right side of it that should be squirting water that indicates the water pump is working. When running at full throttle there will also be some water coming out of the exhaust reliefs in the leg but most of the water comes out through the prop. 45 MPH is respectable for a 90 if you want to go faster you need to go to a larger outboard. You should find out why the tach isn't working it could be the tach itself or it could be the voltage regulator.
                          I love the smell of a two stroke early in the morning

                          Currently running a 1971 Starcraft JetStar powered by an E35QLEDC with the OMS removed and a 4436R

                          Get your copy of the CDI Troubleshooting guide here.
                          http://issuu.com/cdielectronics/docs...owFlipBtn=true

                          Comment



                          • #14
                            Re: getting more speed out of 90 hp johnson

                            I as well have a 16' boat with a 90 Johnson SPL. My motor is well tuned and I believe I am getting the best it has to offer. Below are results based on a prop change I made last year. The prop change really brought the motor to life as well as has it running at optimum RPM range. Since out applications are pretty much the same, this should give you a good measure once you find out what your existing prop is.

                            Old prop 14X17 Michigan Wheel:

                            Top speed = 34 mph (GPS)
                            RPM = 4600

                            New prop 13 1/4 x 17 Solas:

                            Top speed = 42 mph (GPS)
                            RPM = 5300/5400
                            sigpic

                            1997 Glastron GS-160
                            Johnson 90 SPL

                            Comment



                            • #15
                              Re: getting more speed out of 90 hp johnson

                              Originally posted by V153 View Post
                              First fix the tachometer.

                              Yes there should be water coming from the pee hole. And yes the V4s can burn an obscene amount of fuel 'specially when yer gettin on em.

                              I too would recommend starting with a fresh impeller, but then again if you're not getting high temp alarms, providing your alarm(s) work. It's entirely possible there's an obstruction in the tattle-tail hose or fitting. Might could be a worm or a bug holed up in there. It happens.

                              Ya y'oughta be able to find a # stamped/etched into the prop somewhere. Can you post pics?

                              Might surprise some as to just how much performance you can get outa a 90 when it's rebuilt, balanced, and/or dialed in right. This slightly modded '86 has pushed my boat to just under 55mph @ about 6200rpm.

                              Just 'member to use good oil & gas. I run Sunoco premium & Quicksilver synthetic in mine.

                              Good luck on your quest!

                              OK all of us could gain extra performance by doing mods to our motors, let's keep things in perspective.
                              1985 Baretta Vanguard 16ft & 1984 Evinrude 75hp O/B

                              ****Running your motor without water is like peeing into the wind, it's a stupid impulse that is going to be a mess later****

                              Comment

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