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Cost of a tune up?

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  • Cost of a tune up?

    Hey everyone,
    My name is John....
    Last year i purchased a 1975 Mark Twain Round about boat with a Mercury 1500 outboard. I was just wondering how much should i expect to pay for a tune up? When i got the boat i didn't realize that the guy that sold it to me was scaming me because the hydraulics didn't work and when i put the boat into water it started great and ran fine but when i tried to throtle it up, the engine died. The only way that i could get it to full throtle is by dumping the throtle to full right off the bat. Any help would be greatly appreciated. I just need to know if a tune up would help this and how much should i expect to pay for one or should i dump the thing?

  • #2
    Re: Cost of a tune up?

    Well, that depends on what is needed for your tuneup. The price of a distributor cap from Merc is $135. The rotor, if it's bad, is over $400.
    Spark plugs are about 5 bucks. Hard to say on the labor, anyone near you know how to tune up an old MercOB? They should do a compression check and run some power tuner thru it to clean things out, along with some carb adjustment. Carbs may need rebuilt to make it run right. It all takes time and parts. Old parts are expensive. So is labor.
    Don S.

    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.


    • #3
      Re: Cost of a tune up?

      labor in washington is 85-95 per hour thats why i am working on my boat and not paying some one till i have to.



      • #4
        Re: Cost of a tune up?

        Get a compression tester first off. All cylinders should have compression readings within about 10% of one another.

        Do a search in the forums here on "decarb". Follow the procedure for the decarb. You will probably want to remove the carbeuretors and give them a thorough once-over.

        New spark plugs, wires and dist. cap are a must.

        Without a doubt...replace the impeller!!! Muy Importante!
        Replace the thermostats.
        The wetter, the better.


        • #5
          Re: Cost of a tune up?

          ok thanks for the help. I have just another question.... When i decarb my engine do you know what a good decarb would be? I dont even know where i could get it or what i will do with it. I work on cars mostly this is my first boat. And another question that i have is what is a good compression for pistons on a merc 1500.. and does any one have a hydraulic pump laying around? when i hit the tilt/trim controlls all i hear is a motor running when i push the up button and when i push the down button all i hear is a "Click Click" sound. Do you know if this would be the pump or would it be a cilanoid?


          • #6
            Re: Cost of a tune up?

            John, I have owned a '77 Merc 1500 since '80. I have some advice and some tricks.

            If the Trim motor runs(either up or down), check the trim fluid. There is an aluminum screw with a strait slot on the pump. That is the fill. Put some 5W-30 motor oil into the pump resovoir and fill it up. That motor should have one solenoid one (for up) on the Trim bracket. You can bypass the solenoid for testing the motor. The Trim systrm is not self-bleeding. If it has spongyness, you will need to manually bleed it.

            As for your acceleration problem. The carbs do not have accelerator pumps. They need to have a rich idle mixture in order to accelerate. Try richening the idle mixture 1/8 turn (CCW) top carb first. Try to accelerate. Repeat with mid carb, test it again. then lower carb... Start from the top once more. You are trying to get the richest idle mixture the motor will accept and still idle reasonably.

            Make sure the fuel line has no restrictions. Those motors need lots of gas at full speed.


            • #7
              Re: Cost of a tune up?

              maybe i wasn't as clear as i should have been. I can get the thing to run at full speed just fine. The problem is that when i start to accelerate from idle to full i cant go at a steady pace. I have to give her hell. with the hydraulics how would i go about bleeding the lines? if i were to take pictures is there any way that someone could edit them and send them back to me so i know what to do to bleed the lines? (sorry im a FNG when it comes to this whole boating thing.)


              • #8
                Re: Cost of a tune up?

                Hi John and Welcome to iboats!

                The FAQ sections has a lot of good info.
                Here is the decarb process:

                As was said before, get a compression check first, that will let you know if the motor is sound and worth working on.
                Then do the decarb.
                You shoud also get a manual. Even if you don't do the work yourself, it will give you a better idea what the repair shop is talking about.
                Rest in Peace Spinner

                2010 Lowe FM 175 with a 2010 115 Mercury
                Your friend,your partner, your defender,your dog.You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion....by E.F. Henry


                • #9
                  Re: Cost of a tune up?

                  John, Your acceleration problems are likely due to either dirty or mis-adjusted carbs. You can try to adust the idle mixture as I outlined, if you want to attempt to solve the problem.

                  To bleed the trim cylinders you must remove them from the mounting brackets. Leave the hoses on, of course. Face the trim cylinders with the part of the cylinder where the two hoses connect facing directly up. Loosen the bleed screw next to the hose connections. Now run the pump in the up direction until all the bubbles are out. Repeat for the other side. Now reinstall the cylinders. Now open the other bleed screw on the top of the cylinder, next to the grease fitting. Run the pump in the down direction until all the bubbles are gone. Repeat for the other side. Now refill the pump.


                  • #10
                    Sign up today
                    Re: Cost of a tune up?

                    Thanks for the help. I will try to blead my lines once the weather gets above 30. I just called a local marine shop and they said that a tune up will run about 500.00. I'm not sure if i will spend that much on my boat. I only bought it for 900.00. Thanks a lot for the information.