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3055 poor economy/performance pt 2 (attn Vic and others who responded last year!)-gctid569863

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    3055 poor economy/performance pt 2 (attn Vic and others who responded last year!)-gctid569863

    Hey all...

    Last year I started a thread about the poor fuel economy/performance I was getting with my '99 3055 (5.0L). I couldn't get near the top speed or rpms that most other owners were reporting. We talked about all kinds of issues ranging from carbs, to growth on the bottom, to wrong pitch on the props, etc.

    I'd like to update everyone that contributed and run a theory past you...

    I think I have the engine performance in a pretty good spot. I ditched the Holley 2bbl carbs I bought from I5 (I don't recommend them, and others concur) and rebuilt the original Mercarbs myself with great success. Engines ran great last fall, and this spring they started up and idled as if the boat had been running just a week prior.

    Here's what I discovered: The props that are on there now have a pitch of 21. Pretty much everywhere I read about other 3055s, the original props should have been a pitch of 23. Last year some folks suggested I might actually be over-propped and this is why I couldn't reach WOT spec but now I am leaning more towards the carbs being the cause of that problem, especially since almost everything else I've read suggests that the 3055 came with props having 23s.

    Also, looking at the bottom of the boat before it goes in the water, it's actually quite smooth. It does have bottom paint on it so it's not as good as it could be for sure, but it's pretty good.

    So now I am thinking that the reason I was not reaching the speeds that others are at WOT, and therefore not getting good fuel economy, is because my props are pitched TOO LOW. It's like losing the overdrive in your car...you're fuel economy is going to suffer (top speed would too if we didn't have speed limits). Isn't it?

    Also, and this might be significant, last year I had a RIB attached to the swim platform with the arc davits that weighs about 200lbs. When lifting the rib up onto it's davits, the effect on the boat seemed undetectable, but the more I thought about it...having 200lbs hanging that far back on the boat MUST have an effect on the way the boat planes, causing the back to squat down in the water a bit...wouldn't it? Not to mention the air flow issue (rib is up on it's side when mounted, acting like a drag chute!).

    Seems ridiculous that I didn't think of this before, but I figured a 12,000lb boat isn't going to notice an extra 200lbs, but when it's THAT far back I'm sure the 200lbs starts to act like much more.

    Can anyone support or blow up my theory? (be gentle if you're going to blow it up...I don't profess to be an expert!)

    I want to feel like I'm on the right track with the prop theory before I start looking at replacement props. Any prop recommendations from other 3055 owners are welcome as well.

    Thanks!

    K

    #2
    FWIW, I hung a heavier swim platform off my 3055. I noticed the change of the angle of the boat but nothing significant in the overall performance.

    Comment


      #3
      Are you able to hit recommended max RPM's for that engine now, or is it still not getting there? What kind if fuel economy are you getting? If you are underpropped, I would think you would be exceeding max RPM's, assuming everything else in the drive train is in good shape...

      Comment


        #4
        I don't recall the previous conversation. What drives do you have? What is your RPM at full throttle?

        My props are 21s, and I'm definitely over-propped by just a bit. I'm at a little bit of altitude (1700') which may change HP just a little.

        Comment


          #5
          Great point...I've been looking at the aftermarket platforms too. Did you go with the guys in Phoenix? Happy?

          Comment


            #6
            Also a great point...I should be exceeding max rpms if my theory was right. I'll know this weekend, but I don't think so.

            Comment


              #7
              You're OVERPROPPED at 21? Wow...what rpm are you reaching? 1700' feet isn't that much...

              Comment


                #8
                If you call bayliner with your HIN (serial number on the starboard rear), they'll tell you what props the boat came with. I think (not certain) that mine had 23". I had the 5.7 which perhaps allowed a larger pitch than 5.0s. Post back with your WOT RPMs and Speed (use gps and not the factory speedo).
                Doug
                Hanging Loose
                98 Carver 350 Mariner
                2013-
                KRUSTY KRAB
                2001 305
                5.7 BII
                2006-2013

                Comment


                  #9
                  Great point...I've been looking at the aftermarket platforms too. Did you go with the guys in Phoenix? Happy?
                  There are two companies here that make the platforms. I've owned both, and would always choose this one over the other one: http://swim-platform.com

                  That's my 2455 on the front page. It was the mold for the 2455 platform that you can order pre-cut and ready to just bolt in. My current boat came with a platform from the other company. The color match isn't quite right, the no-slip is uncomfortable to sit on, and it's much heavier.

                  You're OVERPROPPED at 21? Wow...what rpm are you reaching? 1700' feet isn't that much...
                  4300 at light load, 4100 at heavy load. Both are too low. I picked up a little bit of RPM by putting in four-barrel carbs, but not a huge amount. The previous owner said they were 21, but I actually haven't verified it myself. I plan to shortly and make a change.

                  Comment


                    #10
                    "SwampNut" post=570232 wrote:
                    Great point...I've been looking at the aftermarket platforms too. Did you go with the guys in Phoenix? Happy?
                    There are two companies here that make the platforms. I've owned both, and would always choose this one over the other one: http://swim-platform.com
                    +1 to that! I looked at both and saw the construction. They are both good but the one Carlos mentioned is simply much better yet lighter.

                    I mentioned that before that you shouldn't see their "manufacturing place"! It is the opposite of their platform quality and one of the worst yards I have seen in a long time.

                    Comment


                      #11
                      "hulakai" post=570006 wrote:
                      Great point...I've been looking at the aftermarket platforms too. Did you go with the guys in Phoenix? Happy?
                      Yes love it, money well spent for sure.

                      Comment


                        #12
                        They are both good but the one Carlos mentioned is simply much better yet lighter.
                        They use a thick balsa core, which is ideal for this. Balsa is super light, but stiff when sandwiched with fiberglass, and is highly resistant to water damage. The other guys use some sort of cheaper but very heavy wood, resulting in over 2x the weight.

                        And yeah, the yard looks terrible, but the results are great. Same guys have done a transom for me, and a number of other smaller fiberglass jobs, always perfect.

                        Comment


                          #13
                          Yep,Kraig did mine too!! Love my platform.

                          Comment


                            #14
                            I agree, Kraig is a great guy and an ex-Bayliner owner (175). In the small platforms they don't use a core only woven glass as it's stronger at less weight than the sprayed Polyester with fibers. When I was there they had a platform in the works which was as big as my entire boat.......

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