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Can I resleeve the cylinders?

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  • Can I resleeve the cylinders?

    I picked up an 85 'Rude 90hp over the weekend for the low low price of $Free.99. The catch was, I had to rebuild the powerhead. I spent part of Saturday and most of the morning Sunday taking the motor apart down to the powerhead.

    Here's the "sitch". The number 2 piston is fried. The guy I got the motor from said the VRO quit working on the lake one day. When they got back to the boat ramp, he pulled the plug and it was caked with aluminum. He put the plug back in and quit using the motor. That was about 4 years ago. When I pulled the cylinder head, I realized the severity of the damage (if I had a picture with me, I'd post it but I'll try to remember to do so tonight).

    Anyway, the guy told me he had the motor rebuilt back in the mid 90's. What he remembers is just having the cylinders resleeved and not having new pistons put in. Just new rings. I noticed after taking the cylinder cover off the #1 and 3 pistons, the pistons are stamped with "030". I'm no genius, but my pea sized brain leads me to believe the pistons are .030 pistons. Additionally, the # 2 cyl has a small amount of aluminun melted to the wall and the #3cyl has some grooves in it.

    My questions are, does the "030" mean they're 30 over pistons and if so, can I have the sleeves removed, new sleeves put in and then put new .030 pistons in?

    I plan on installing a new rebuild kit with new pistons, wristpins, gaskets, etc. I figure if I'm going to have the powerhead broke open, I might as well make it as fresh as possible. Is there anything else I can do to the powerhead along the lines of cleaning the insides?

    Any other suggestions/comments?


  • #2
    Re: Can I resleeve the cylinders?

    Welcome!!

    Obviously your guy isn't an outboard mechanic. Yes, the pistons are oversize. Yes, you can resleeve the block. However (don't ya just love the "howevers"?), it fairly expensive. Thats -obviously- why he didn't do it last time.

    There are .044 and .064 oversize pistons for your motor so you've got quite a lot of room to go yet before you need to consider resleeving. If it were mine I'd get it apart and to a marine (not automotive) machine shop. Let them measure it up and go from there.

    BTW - the oil injection system on an OMC / BRP motor cannot pick on one cylinder. If the top of your piston is burned it's most likely an ignition problem. That's something you'll have to check out when you get it back together so it won't happen again.

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    • #3
      Re: Can I resleeve the cylinders?

      You are correct about .030 and you can have the cylinders resleeved. The damage is probably from running lean. It is unlikely that the cost of resleeving is economically justified on that particular engine. Why not let your specialist have a look at it first and see if it can be repaired without new sleeves.

      The fellow who does my blocks won't touch a block like that. He says its too easy to find one that hasn't been bored out before.

      Comment



      • #4
        Re: Can I resleeve the cylinders?

        Originally posted by Dhadley View Post
        Welcome!!

        Obviously your guy isn't an outboard mechanic. Yes, the pistons are oversize. Yes, you can resleeve the block. However (don't ya just love the "howevers"?), it fairly expensive. Thats -obviously- why he didn't do it last time.

        There are .044 and .064 oversize pistons for your motor so you've got quite a lot of room to go yet before you need to consider resleeving. If it were mine I'd get it apart and to a marine (not automotive) machine shop. Let them measure it up and go from there.

        BTW - the oil injection system on an OMC / BRP motor cannot pick on one cylinder. If the top of your piston is burned it's most likely an ignition problem. That's something you'll have to check out when you get it back together so it won't happen again.
        Thanks for the Welcome! You mention ignition problem. What should I be looking for when I get it back together?

        With regard to the .044 pistons. Would that mean just having the current cylinders/sleeves bored out a little more?

        ezeke,
        You mentioned running "lean". The guy I got the motor from put the carbs and exhaust on the motor from a 140hp motor. My buddy in Iowa (outboard mechanic) said that would cause it too run lean but he doesn't think that was the cause of the problem. Should I consider putting the original carbs and exhaust back on then?

        Comment



        • #5
          Re: Can I resleeve the cylinders?

          Various conditions cause the mix to have too much air or too little gasoline in the combustion chamber at the point of ignition. When that happens the fire is much hotter than normal and can do things like melt aluminum.

          Not correcting such conditions in the process of rebuilding will pretty much guarantee that the engine will have to be rebuilt again.

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          • #6
            Re: Can I resleeve the cylinders?

            If I keep the 140 carbs and exhaust on the motor, what should I do so it doesn't run lean?

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            • #7
              Re: Can I resleeve the cylinders?

              A lot of small things help, like being sure that the fuel system is absolutely air tight, including all connections, gaskets and fittings. Also, carburetors should be carefully rebuilt, using new parts from the kit. The orifice sizes should be checked to be sure that they are correct.

              I read a report once that talked about guys running racing boats with nearly empty fuel tanks. When they turned sharply they pulled air into the fuel line and damaged their engines - melted pistons to be exact.

              BTW, I am an enthusiastic boater. Dhadley is the expert, give appropriate weight to the information you are getting from us.

              Comment



              • #8
                Re: Can I resleeve the cylinders?

                I definitely appreciate the information thus far I'm by no means a genius when it comes to this stuff so I'm learning as I go and asking lots of questions.

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                • #9
                  Re: Can I resleeve the cylinders?

                  Yes, all you need to do is bore the cylinders for the .044 pistons. Not really a big deal.

                  Putting the 140 style carbs on a 90 block is kinda an overkill. The 90 will have smaller ports so it's hard for the 90 to take advantage of all that extra fuel. But (here we go again)- while the motor is apart for boring you can have the ports opened up the the 140 size. Really simple since the block will be stripped down anyway.

                  Comment



                  • #10
                    Re: Can I resleeve the cylinders?

                    If you need a block I have one, still have yours checked first. If you need it let me know and I will check it out and bore it if needed
                    When in doubt,Trim it out!!!
                    Business Owner & Certifed Technician
                    Boats I own & use
                    20ft Javlin w/250 Junkrude
                    17ft Bullet w/200 Merc (SOLD!!)
                    13ft Allison w/150 I-6
                    17ft Hydra-Sport 175GT
                    15ft Allison w/75 Stinger(project)
                    14 x 48 Drifter with 1100SS Merc

                    Comment



                    • #11
                      Re: Can I resleeve the cylinders?

                      Originally posted by Faztbullet View Post
                      If you need a block I have one, still have yours checked first. If you need it let me know and I will check it out and bore it if needed
                      Faztbullet,
                      I sent you a private message.

                      Comment



                      • #12
                        Re: Can I resleeve the cylinders?

                        Originally posted by ezeke View Post
                        I read a report once that talked about guys running racing boats with nearly empty fuel tanks. When they turned sharply they pulled air into the fuel line and damaged their engines - melted pistons to be exact.
                        Bro-in-law's races Grand National Stock Cars, and has learned the hard way, that when the power significant picks up, it's already too late to turn it off, running low on fuel, running out of gas, melts a set of pistons, EVERY time! And we think our outboard engines cost a lot.

                        Comment


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