2003 300da speeds

Discussion in 'Sport Cruisers' started by chris sirizzotti, Jul 8, 2019.

  1. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    Can anyone tell me what the typical cruising speed At what rpm and top speed at what rpm should be on my new to me 2003 300 Sundancer has bravo3's with twin 5.0 liters
     
  2. Bridog

    Bridog Well-Known Member GOLD Sponsor

    Oct 4, 2006
    Gulf Shores AL / Brick NJ
    2016 19SPX OB
    Mercury 150 4S OB
    IMG_3157.PNG From an article on Boattest.
     
  3. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    shit mine wont go over 18 knots it runs between 3500 rpm and 4500 rpm with no speed change no idea whats going on there? boat only likes a small amount of trim before it starts slipping so dont raise the drives much. just put new plugs, oil, fuel, and fuel water separators on both engines. any suggestions to look at?
     
  4. Bridog

    Bridog Well-Known Member GOLD Sponsor

    Oct 4, 2006
    Gulf Shores AL / Brick NJ
    2016 19SPX OB
    Mercury 150 4S OB
    Bottom and props clean? You should get 4600-5000. I had the 350 Mags and WOT was about 47MPH. Always seemed to get about 1.2 MPG on average. Boat never liked trim. I always had it all the way down til up on plane, then just a touch up. I'll let the real experts chime in on what may be going on. Good luck Chris.
     
  5. Ididntdoit

    Ididntdoit Well-Known Member GOLD Sponsor

    Dec 5, 2007
    Newport, RI
    300 Sundancer
    5.0MPI Bravo III
    Those Boat Test numbers look a little optimistic to me....with a "full load" in "normal" conditions I generally run 3800 RPM for 30 MPH at right about 1 MPG - Like you, I cant trim the drive much, if at all......seems odd that you can run up to 4500 on plane and get no more speed than you do at 3500 - is this both motors? No prop hubs to "spin" on BIII's and I would doubt its the couplers....are the drives original (I believe 2.20 ratio)? what props? Also - what HP are the 2003 5.0 MPI's - mine are 260
     
  6. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    i'm assuming there original drives and yes they are 260hp and can get them both up to 4500 rpms. was out yesterday and running at 3800 rpm on both motors the boat wont go more than 18 knots right around 20mph the props are mercury marine # 48-823664 22 pitch
     
  7. Ididntdoit

    Ididntdoit Well-Known Member GOLD Sponsor

    Dec 5, 2007
    Newport, RI
    300 Sundancer
    5.0MPI Bravo III
    You should be getting at least a couple of hundred more RPM at WOT.....My props are 20 pitch - I would check the drive ratio too
     
  8. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    went out this weekend and checked fuel pressure at idle up to wot. between 38-40 PSI. Normal? Still wont go past 4000 rpm @18-20 nots. I would think she would be doing around at least 30 MPH at that rpm no?
     
  9. Ididntdoit

    Ididntdoit Well-Known Member GOLD Sponsor

    Dec 5, 2007
    Newport, RI
    300 Sundancer
    5.0MPI Bravo III
    4000rpm max is no bueno - need to hit at least 4600 WOT - If the motors are in good shape (compression, tune up etc) and trimmed down you need different props - at 3800rpm I'm doing 28-30mph depending on conditions and load once on plane - your still pushing water thats why you aren't seeing the right speed......again, confirm all is well with the motors and change the props
     
  10. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    what are the stock props supposed to be?
     
  11. Ididntdoit

    Ididntdoit Well-Known Member GOLD Sponsor

    Dec 5, 2007
    Newport, RI
    300 Sundancer
    5.0MPI Bravo III
    for '03 you have the stock listed props.....by '05 the same exact boat with the same exact motors are listed as 20p stock......my guess, SR realized the 22p was wrong]/ didn't work and corrected it.....if I had to replace my props, i would drop to 18p or 19p like I said above
     
  12. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    20190220_094146.jpg
    OK thanks makes sense. Anyone have any leads on some good used 19p props? or need my 22p let me know.
     
  13. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    IMG_4230.JPG Our 260 was new in 1979 so we had the 5.0 but the old drive. Still the boat cruised at 21 MPH. It got good mileage but was no speed demon. The 5.0 is a great engine that will last for a very long time if you run it at 3000 to 3150 RPMs. Consistently running it above that RPM will shorten its life. We put 4000 hours on that 260 and it was a good running boat with high hours when we sold it.
     
  14. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    My problem is I need to be at least 3600 RPM to cruise at 16 nots. I would like to be @ 3200-3400 RPM cruising @ around 25 nots
     
  15. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    I see they sell a 14.25" and a 16" prop what do you guys recommend I go with?
     
  16. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    and they going 3 blade rear and 4 blade front i see?
     
  17. Ididntdoit

    Ididntdoit Well-Known Member GOLD Sponsor

    Dec 5, 2007
    Newport, RI
    300 Sundancer
    5.0MPI Bravo III
    I believe the 4 blade is the rear - and you use both - 16" rear and 14.25" front - my 20p sets may be available as Im thinking about hill marine props as I often run heavily loaded.......but you may want to consider the same if buying new....
     
  18. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    IMG_4230.JPG FullSizeRender.jpg
    You may have some mechanical or propping issues. We owned a 300WE that we bought new in 1986. That is a different boat than your newer 300. We cruised that boat at 3150 when it was filled up with fuel. As we burned off fuel and got lighter, we would back it down to 3000 RPMs and it would gradually gain speed as the fuel load lightened. It was not a slow boat and appeared to be perfectly matched to the twin 5.0s. Loved that boat. One of SRs better models in my view.
     
  19. chris sirizzotti

    chris sirizzotti Member

    88
    Feb 6, 2019
    2003 300DA SUNDANCER
    MERCRUISER 5.0 W/BRAVO III
    UPDATE!! After a good tune up, new fuel 3/4 of a tank, fresh water tank full, 5 adults 2 kids fridge full of beer and a cooler full of food and ice plus misc gear. The boat will cruise @3100 rpm doing 34-35 MPH and get on a plane no problem. but here's the funny thing #1 it still wont rev past 4000 rpm (still have not gps top speed) just wondering if this is normal or should i still look into mabey going down to a 20 pitch?? The funny thing #2 (most weight i ever had on it) is the next time I took it out I had the same fuel 3/4 tank and all the same gear, but this time had 9 adults and 1 kid (not my typical load) every one was on the deck it would not plane at all. I had 5 of the adults go down below and which 2 of them laid on the bow bed. she finally planed once on a plane she cruised all day with same specs pretty much @3100 rpm going approx 30-32 mph. I get thats alot of passengers i just wanted to throw that in there. Typically I have the first scenario on board. (3-4 adults 2 kids).
     
  20. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    IMG_4230.JPG You need a prop that will get your WOT rpm into the 4400-4800 range. The prop you are running is overloading your engine and will shorten its life.
     

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