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    • Cummins Marine Forum Topics
    • Fuel burn with twin QSB 480 vs twin QSC 500

      This topic has 2 replies, has 3 voices, and was last updated byTony Athens 2 years ago

      February 19, 2022 at 4:55 am Iā€™m comparing a 2009 Sea Ray 44 flybridge with twin QSC 500 straight shaft with a 2009 meridian 441 flybridge with twin QSB 480 v-drive. Boat displacement and length are similar. I like to go fast and slow but from my research it seems that somewhere around hull speed or 700-900 rpm or 7-9 knots, the QSBā€™s donā€™t do any better than 1 or 2 mpg whereas the QSCā€™s maybe get 5-7 mpg. At higher RPMā€™s the burn is pretty flat and similar for both. Iā€™m wo…

      Started by: Thomas Riley in: Cummins Marine Engines

      2 Replies
      February 19, 2022 at 11:22 am Instruments/gauges, or ?? is wrong.. The vessel with less weight, less windage and the best ‘bottom /running gear” will typically get the best MPG at hull speeds assuming all is in “ass new condition” ..Longer LWL’s will increase hull speed some in some cases and some round chine narrow “east coast designs” can be “slipperier” in some cases at speeds below 10 kts.. ……………

      Last Post by: Tony Athens posted: 2 years ago

    • Rebuilt turbo put on 2008 QSB 5.9l 480

      This topic has 3 replies, has 3 voices, and was last updated byThomas Riley 2 years ago

      February 14, 2022 at 7:58 pm Iā€™m considering buying a boat with twin QSB 5.7l 480hp (2008) v-drive with about 1200 hrs. It looks like the 1000 hr service (or maybe I should say a service) was done in April of 2019. Do the pics and service invoice tell any story? Does the paint job on the motors, which seem to have a bit of overspray, a little sloppy indicate anything?

      Started by: Thomas Riley in: Cummins Marine Engines

      3 Replies
      February 18, 2022 at 5:08 am Iā€™m not very far along in the investigation to be able to give the more pertinent info. However I need to verify my thoughts against yours as I go through the education process. Buying a boat is tougher these days. So many are neglected and the prices are high. But Iā€™ll find my boat and it will have Cummins and Iā€™ll be better educated and supported and that is THANKS to you guys Tony, Rob and Steve. Youā€™re much appreciated.Ā 

      Last Post by: Thomas Riley posted: 2 years ago

    • QSC 600hp or QSM 11 715hp (dry turbo) same boat

      This topic has 4 replies, has 3 voices, and was last updated bySteve Lewis 4 years ago

      November 2, 2019 at 7:13 am Hi Tony I plan to buy a Back Cove 41 and have the option of either the QSC 600hp or the QSM11 715hp dry turbo. Iā€™ve read opinions on both in this approximately 15 ton planing boat with some saying the QSC is under powered and others saying the QSM has heat related problems to to the turbo/manifold if the extra horse power is actually used. Assuming the boat is correctly propped and Predominantly run at say 80% or less than max rated RPM, which m…

      Started by: Thomas Riley in: Cummins Marine Engines

      4 Replies
      November 3, 2019 at 6:53 pm when looking at THIS boat and THESE engines you can not look at the rated HP as a determinant. You have to look at real world usable cruise power and that is 400HP for both engine options. The big difference is that the QSC can run up to rated power for short bursts(1hour for every 8 hours of use as per the published performance curve) where as the QSM will suffer damage to the exhaust manifold when pushed beyond 20GPH @2050-2100. The dry tur…

      Last Post by: Steve Lewis posted: 4 years ago

    • Is it worth repowering a 2008 Sabre 42 flybridge with Cummins QSCā€™s

      This topic has 1 reply, has 2 voices, and was last updated byTony Athens 4 years ago

      August 4, 2019 at 11:32 am So I want to buy a Sabre 42 flybridge, I want the planing speed, the look, the quality and the fly. I want one that is a 2008 or older because I do not want pod drives and all newer Sabreā€™s are pod driven. However the only ones for sale have the Yanmar 6cx-gte or 6ly-etp and Iā€™ve educated myself on those motors to the point that Iā€™m not willing to own them but I believe I could buy the boat for $300-350k. Alternatively I could buy the sister Bac…

      Started by: Thomas Riley in: Boats & Repowers

      1 Reply
      August 4, 2019 at 3:28 pm Simple answer to a simple question–NO you will not get your $$ back unless you can buy the boat for under $50K.. What you will get if the repower is done “100% Seaboard Right” is a very usable boat that would meet you needs for years to come…. Tony

      Last Post by: Tony Athens posted: 4 years ago

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Viewing 4 topics - 1 through 4 (of 4 total)