Welcome Guest - Sign Up today
Welcome Guest - Sign Up today

Announcement

Collapse
No announcement yet.

'76 EVINRUDE 9.9 WATER PUMP problem?

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

  • '76 EVINRUDE 9.9 WATER PUMP problem?

    History: I bought this motor this winter for a mere $100. The guy said it wouldn't move well on higher revs, "like the clutches were slipping" is what he said. Well news to me there are clutches so I figured the prop was spun. I ordered a new prop, carb kit, and plugs. Anyway, after replacing that stuff I was finally able to start the motor this last weekend. It ran well but I couldn't find any water coming out a "pee hole" to make sure the water pump was working. Being cautious, I shut the motor down and did some research come to find out the 74-76 motors didn't have one from factory. However, before I figured this out last night I ordered a water pump kit. Being kind of mad I maybe wasted money I decided to take the lower unit off and replace the impeller anyway. Well, I'm glad I took it all apart because I found one of the blades on the impeller was almost broke all the way through. (see pictures below). It was also packed full of sand and is now clean.
    Which leads me to my main question:
    Is there anyway, or has it been done before to directly attached a garden hose to the copper tube in the lower unit and push water through the powerhead to make sure there isn't any blockage or will it not circulated because the thermostat isn't tripped? I want to try and flush the motor and to know %100 there isn't any blockage in the powerhead anywhere.
    What is everyone's experience and recommendations for this? Click image for larger version

Name:	9.9 IMPELLER1.jpg
Views:	1
Size:	132.2 KB
ID:	7195464Click image for larger version

Name:	9.9 IMPELLER2.jpg
Views:	1
Size:	135.8 KB
ID:	7195465Click image for larger version

Name:	LOWER HOUSING1.jpg
Views:	1
Size:	131.2 KB
ID:	7195466Click image for larger version

Name:	LOWER HOUSING3.jpg
Views:	1
Size:	139.8 KB
ID:	7195467
    Thanks for any replies.

  • #2
    Re: '76 EVINRUDE 9.9 WATER PUMP problem?

    That motor's telltale is water out the exhaust relief hole on the back, just under the pan. When you start it up, it just produces an almost unobservable mist. You can feel it if you put your hand near the exhaust relief hole. In about 10 to 15 seconds a noticeable spray will begin. This spray is happening as the T-stat slowly starts to open. As you run the motor it will alternate from a spray to a stream as you lower and increase RPMs.

    Good job in catching that broken impeller. Impellers must be changed when they are still working since you only get about 60 to 120 seconds of notice after they stop working and when your motor starts to burn up.

    I imagine you could rig a garden hose to connect to the bottom of the copper tube but it would not flush the chamber around the cylinder walls since the T-stat is not open.

    The other test to see how well the cooling system is working is to put your hand on the cylinder head while the motor is running. If you can leave your hand on the cylinder head for 3 to 5 seconds, she is cooling just perfectly. If you have to pull your hand away and especially if profanity gets used, the powerhead is heating up too much.
    Last edited by OptsyEagle; April 1st, 2014, 08:31 AM.

    Comment


    • #3
      Re: '76 EVINRUDE 9.9 WATER PUMP problem?

      Thanks for the quick reply. I might fab up something to hook the garden hose to the bottom of the copper tube then try running it to see if I can get water to come out. Then replace the pump when that comes in then I should be good to go.
      How often do the thermostats go out on these? Think I should replace that as well before the start of the season? Looks like I have maybe 1 but probably 2 more weeks before the ice is gone here in Wisconsin.
      Thanks,

      Comment


      • #4
        Re: '76 EVINRUDE 9.9 WATER PUMP problem?

        Most t-stats tend to fail in the open position but not always. I can't say how long they will last. Getting at the t-stat on that motor is a little annoying. I think the cover latch needs to come off to have enough room to remove the water jacket cover and then the t-stat. That latch is a real pain to put back on. If you find a 10 year old, their small fingers can help. lol.

        As for the running test. Don't put too much pressure on the water. Your house water pressure will go significantly higher then the pressure from that impeller and some of the grommets may not like very high pressures. Keep running the finger profanity test by touching the cylinder head regularly and seeing if you have a strong urge to swear some indecent words. It will be hot but you should be able to hold your fingers on it for 3 to 5 seconds when operating properly.

        Comment


        • #5
          Re: '76 EVINRUDE 9.9 WATER PUMP problem?

          By the way. This is my 1976 15 Hp Evinrude. It is pretty much the identical motor as yours except with a little bigger carburetor.

          Anyway, if you look closely at the pictures you can see the sort of spray it is giving out the back of the motor. The first two pictures are a slow idle, after the 15 seconds or so when the t-stats opens. The 3rd picture is the stream you get when it is flying across the water.
          Attached Files

          Comment


          • #6
            Re: '76 EVINRUDE 9.9 WATER PUMP problem?

            Thanks for the pictures. I really don't remember that "mist" spraying out the back but I don't remember checking. I'll know more this weekend when I have time to run it ouside again.
            Here is a thought right, wrong, or indifferent, what if I taped off (with duct tape or aluminum tape) the upper set of holes on the water exit on the lower unit. NOT the intake by the pump but where the water is dropped down leaving the motor. That would then fill that back cavity up and force a stream of water out of the upper rear hole (where the mist comes from at idle)

            My only concern would be that would create more back pressure on the system and mess something else up? This way I have a definitive output of water to know everything is working correctly.

            Comment


            • #7
              Re: '76 EVINRUDE 9.9 WATER PUMP problem?

              I wouldn't do that. I don't think it would tell you much anyway. Also, the holes closest to the impeller is an exit hole for water not an intake. In any event, what is happening is the water is shooting through the engine at different water pressures depending on the RPM of the motor, at the time. When the motor first starts up, there will be water out the exhaust relief hole but it is only noticeable by putting your hand behind there and feeling the mist. As the t-stat opens and the water comes through at a slightly different angle, more of it gets directed to that exhaust relief hole, and shows up as a spray out the back, although most of the water bypasses and falls down to the exit holes below. As the RPM of the motor increases and the water pressure increases, more and more water hits that upper hole and is visible.

              In my pictures above, that more solid stream, that is shown in the picture of the moving boat, will move closer to the motor as the RPMs increase and will move further away as the RPMs decrease. Still visible all the time, but it means that as the water pressure increases or decreases the angle of the water flow changes, changing the amount and direction of the water that makes it out the exhaust relief hole.

              I have attached a diagram that may help explain the water flow in these motors. It was a diagram to show how to install a tell tale hose but it still gives a good view of the direction of most of the water in your motor.
              Attached Files
              Last edited by OptsyEagle; April 1st, 2014, 11:28 AM.

              Comment


              • #8
                Re: '76 EVINRUDE 9.9 WATER PUMP problem?

                Do not use tape on those lower holes !!!---Just install the new impeller and enjoy the motor.

                Comment


                • #9
                  Re: '76 EVINRUDE 9.9 WATER PUMP problem?

                  If you haven't done so you should try to clean out the crud that gets into the cavity in front of the water pump where the shift rod is. There is a hole there that is used to ensure all the water drains out and that crud can clog it up. I just scoop it out and spray it with water.

                  Also, when you put the lower unit back up you should put some moly lube on the driveshaft splines (try to avoid getting any on top of the drive shaft, just coat the splines). This will ensure the drive shaft doesn't seize into the powerhead, so when you change the impeller again, it doesn't get stuck. That new impeller should be changed at a minimum of every 5 years even if the motor is not used much.

                  Comment


                  • #10
                    Re: '76 EVINRUDE 9.9 WATER PUMP problem?

                    a think author of this post run Johnson motor, lower unit looks green

                    Comment


                    • #11
                      Re: '76 EVINRUDE 9.9 WATER PUMP problem?

                      Blue or green they are all the same parts !!!

                      Comment


                      • #12
                        Re: '76 EVINRUDE 9.9 WATER PUMP problem?

                        I know not to tape the lower holes. I was thinking maybe the upper holes to direct the water out the hole on the top where the "mist" comes out at idle and a stream comes out with running. That way when idling in my driveway in a tub, I could verify that water is being circulated. I'll wait for the new impeller and proceed from there.

                        It's an evinrude based of the serial number but was on a duck boat and painted camo.
                        Last edited by sledneck22; April 1st, 2014, 02:16 PM.

                        Comment


                        • #13
                          Re: '76 EVINRUDE 9.9 WATER PUMP problem?

                          Originally posted by OptsyEagle View Post
                          If you haven't done so you should try to clean out the crud that gets into the cavity in front of the water pump where the shift rod is. There is a hole there that is used to ensure all the water drains out and that crud can clog it up. I just scoop it out and spray it with water.

                          Also, when you put the lower unit back up you should put some moly lube on the driveshaft splines (try to avoid getting any on top of the drive shaft, just coat the splines). This will ensure the drive shaft doesn't seize into the powerhead, so when you change the impeller again, it doesn't get stuck. That new impeller should be changed at a minimum of every 5 years even if the motor is not used much.
                          Good point with the lube and was planning on doing so. Thanks.
                          Also, the front cavity was completely caked and coated with said and crap. I have cleaned it best it gets and rinsed thoroughly. But I didn't know it had a drain to remove excess water.

                          Comment


                          • #14
                            Re: '76 EVINRUDE 9.9 WATER PUMP problem?

                            Yeah, you should be able to see a little hole on the outside at the very bottom of the lower unit. That is a drain hole for the water.

                            Your test with taping would not tell you much. If you have any restriction of water it is not happening near that exhaust relief hole. It would most likely be the upper water tube grommet if it was restricted anywhere, or the t-stat possibly. If you did tape up the exit holes and fill it with water it would just leak somewhere else. Once the water gets up the tube and through the powerhead, it is not really a totally sealed entity anymore.

                            I have attached a photo of my motor without the powerhead on it. I believe the water comes out of the power head and is directed to that little hole on the left. On the other side of the hole is a cavity and the exhaust relief hole that you see on the outside of the motor. That hole cannot really be seen in my photo, but I believe it is close by. As the water gushes down that cavity some of it comes out the exhaust relief hole and most goes out the exit holes at the bottom.
                            Attached Files

                            Comment


                            • #15
                              Sign up today
                              Re: '76 EVINRUDE 9.9 WATER PUMP problem?

                              Alright. I was just thinking I could force water out the exhaust relief hole to prove I have a decent amount of water flow.

                              Comment

                              Working...
                              X