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04 Monterey 265 CR with Merc MAG 350 MPI B-3 (2.1 G-R) ?

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  • 04 Monterey 265 CR with Merc MAG 350 MPI B-3 (2.1 G-R) ?

    I have been looking for a post like the one in the following link for so long ... and finally I got it for a reference point!,,,http://forums.iboats.com/forum/gener...vo-iii-or-both

    I experience exactly the same problems has half_fast with his Sea Ray 270, my boat being a Monterey 265 CR of 2004 with Mercruiser's MAG 350 MPI (5.7L, 300 HP), gear ratio 2:1 and original B3 props (pitch 20, 3 by 3). In fact it is nearby a 280 boat since it was sold by Monterey later on as 270 and 275 Cruiser or Sports Cruiser with exactly the same hull design.

    My performance problem is even worse than half-fast's, considering that I am already using 20" propellers and the limited engine power: Very long time needed to get on plane. On plane at 3500 rpm. WOT rpm's should be 4600 - 5000, but I can just reach 4100 (at 'only' 30 mph).

    Since I boat in the Mediterranean, choppy sea is predominant condition: Fully loaded I won't even get really on plane :-(
    Another owner with the same boat and a 320 HP Volvo Penta reported max. speed of 60 kph (37 mph) at 4500 rpm to me.

    Antifouling is in bad condition. I will redo it and this action may help to increase 100 - 200 rpm. But I can only drop pitch to minimum 18". So I can gain only 400 rpm.

    Has anyone experienced the same problems on a Monterey 265 - 275 CR? Any additional ideas to perform better? Would have been nice to hear how half-fast's story ended.

    I am also evaluating changing to Hillmarine's B3 Signature 4 by 4 prop set. Or should I keep a 3 blade rear prop? What about SOLAS 4 by 3? In both cases I will probably loose speed. Or simply keep to a Mercruiser 3 by 3 prop set at pitch 18? But would this solve the hole shot problem?

    Thanks in advance for any suggestions!
    Last edited by Fun Times; September 22nd, 2017, 04:58 AM. Reason: Added reference link of an archived topic to be able to create a new topic for you nifego per iboats wishes...Thanks!

  • #2
    how is the health of the motor?
    1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - http://forums.iboats.com/forum/owner...988-rogue-2420

    Past Boats
    1970 Wooster Hellion - Merc 9.8
    2002 SeaRay 190BR - 5.0 - A1G2 - "Cheasheads in Paradise"
    1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

    What’s behind you doesn’t matter.Enzo Ferrari

    Comment


    • #3
      The summation recommendation from that other post was gear ratio change to the 2.2, which I tend to agree with. And you are right, your situation is even worse, the 5.7 needs more help than just a prop swap with that much load in my opinion.
      _

      Comment


      • #4
        This instinctively sounds like an engine related problem. Perhaps one of the well known mpi glitches. Have you had it plugged in and fault read recently ?
        One of the guys in my marina has a rinker 260 with the same engine and drive. I'll see what he has. Pretty sure it's 3x3 23" though. Will likely be a similar weight. My friend also had a maxum 2400sc with same engine and drive. They were 3x3 26". Lighter boat though.
        With your low pitch, I'm pretty sure it should be like a rocket out the hole and I may even say that the props weren't from the factory.
        With regards to a 4x3....wouldn't bother. The twin prop set up on the bravo pretty much has all the bases covered and 4 blade should not be required.
        Have a wee look at the distributor cap and rotor. These need replaced every other year at least anyway.

        Comment


        • #5
          A 26ft boat is a lot of mass to accelerate for a 5.7L. Twin engines or a 7.4L would be a better choice. A boat that size will never launch like a rocket, it will take its sweet time. I suppose with twin 7.4s it would move quick
          If your engine is in good mechanical shape, in tune, and the tach is accurate, your only real option is a reduction in pitch of the props, if you are already at the low end of the pitches, then perhaps a gear change(that gets expensive real quick).

          Comment


          • #6
            Jimbo...agrww it will never be a rocket ship literally out the hole, but plenty of similar sized boats manage just fine with that engine and drive set up. Surely a really popular spec for similar boats. My marina is full of them. They all seem to manage well.
            The 7.4 will be heavier and older technology. Really poor fuel consumption compared to the 350 mpi and only an extra 20/30hp ? Surely he wouldn't be thinking of this.
            Not unless you mean a brand new 7.4 mpi or 454 (what ever it is). This would mean a massive financial cost to fit and surely not a sensible option.
            I'd Defo check the function of the engine before messing with props. Seems underpropped to me with that ratio.
            On a similar note...what doesn't help these types of boats is having a massive fuel tank way aft and all seating there too. I suppose it's part of the overall design to have more room, but sure doesn't help. Especially if the tank is full. It's like carrying an extra 3/4 people on the back end of the boat.
            Surely it pays dividends to only have what fuel you need onboard.
            It's like my old mans boat. It hold over 1000litres of fuel. He insists on keeping it topped up. He would be as well carrying a small Honda on the davits !

            Comment


            • #7
              It is not always about HP, larger displacements produce more low end torque. A 7.4 and 5.7 may have same HP rating but completely different torque curve with top HP at noticeably different RPM's. Just saying the 7.4 could probably get it moving and planing sooner.
              _

              Comment


              • #8
                Originally posted by QBhoy View Post
                The 7.4 will be heavier and older technology. Really poor fuel consumption compared to the 350 mpi and only an extra 20/30hp ?
                all these motors are old technology (the 5.7 being older than the 7.4). the fuel delivery system may have been updated along the way, however both of these motors are technology dinosaurs. all internal spark-ignited mass-produced consumer grade motors burn 0.4# of fuel per HP per hr. that is the BSFC value for a spark ignited motor. so fuel burn is dependent on how much power you are needing / commanding more so than the vintage of the motor's design.

                back to the OP's issue. I know plenty of 25-28' boats with small blocks and duo-prop drives (both volvo and merc). all hit correct WOT range, all get on plane, most top out in high 30's, low 40's. the OP's boat has neglected bottom paint (per post #1), which means he probably has an entire reef starting on his keel. that in and of itself is worth a few mph and RPM

                if his 350 mag (aprox 350hp at crank) is only able to get to 4100 RPM, either he is propped wrong, wrong gear ratio, or more likely the motor is not healthy. with 20p's he should be able to get on plane quickly and hit 4500 RPM. I would recommend that the bottom be attended to, the overall health of the motor needs to be assessed prior to spending money on props. would hate for the OP to spend money only to find the flappers long since fell to the bottom of the y-pipe and were plugging up the exhaust flow (happens often)

                on a side note - i do agree that the boats of this size beg for more power and low end torque. either a 6.2 keeping with the SBC's or a BBC should have been in the boat from day one. Even a diesel
                1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - http://forums.iboats.com/forum/owner...988-rogue-2420

                Past Boats
                1970 Wooster Hellion - Merc 9.8
                2002 SeaRay 190BR - 5.0 - A1G2 - "Cheasheads in Paradise"
                1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

                What’s behind you doesn’t matter.Enzo Ferrari

                Comment


                • #9
                  Originally posted by Scott Danforth View Post

                  all these motors are old technology (the 5.7 being older than the 7.4). the fuel delivery system may have been updated along the way, however both of these motors are technology dinosaurs. all internal spark-ignited mass-produced consumer grade motors burn 0.4# of fuel per HP per hr. that is the BSFC value for a spark ignited motor. so fuel burn is dependent on how much power you are needing / commanding more so than the vintage of the motor's design.

                  back to the OP's issue. I know plenty of 25-28' boats with small blocks and duo-prop drives (both volvo and merc). all hit correct WOT range, all get on plane, most top out in high 30's, low 40's. the OP's boat has neglected bottom paint (per post #1), which means he probably has an entire reef starting on his keel. that in and of itself is worth a few mph and RPM

                  if his 350 mag (aprox 350hp at crank) is only able to get to 4100 RPM, either he is propped wrong, wrong gear ratio, or more likely the motor is not healthy. with 20p's he should be able to get on plane quickly and hit 4500 RPM. I would recommend that the bottom be attended to, the overall health of the motor needs to be assessed prior to spending money on props. would hate for the OP to spend money only to find the flappers long since fell to the bottom of the y-pipe and were plugging up the exhaust flow (happens often)

                  on a side note - i do agree that the boats of this size beg for more power and low end torque. either a 6.2 keeping with the SBC's or a BBC should have been in the boat from day one. Even a diesel
                  Totally Scott... I'm glad you agree with my points. Although, I think the 350 mpi magnum is only 300hp at the prop. You may be right about the crank ?
                  Also agree, these engines are dinosaurs. In comparison to car engines.
                  I often wonder how the engine in my car would get on in a boat. Boat engines seem to be so far beyond the times. Although I do like the thought of a solid, tri d and tested GM V8 small block. Not futuristic tech, but solid and reliable.
                  My car has a 3.0 twin turbo Diesel engine in it which produces 305hp. God I wish it was in my boat.....or maybe not...it wouldn't sound as good through the Corsa exhausts. Haha

                  Comment


                  • #10
                    Audi/VW has the 3.0 and 4.2 TDI motors in marine versions
                    1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - http://forums.iboats.com/forum/owner...988-rogue-2420

                    Past Boats
                    1970 Wooster Hellion - Merc 9.8
                    2002 SeaRay 190BR - 5.0 - A1G2 - "Cheasheads in Paradise"
                    1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

                    What’s behind you doesn’t matter.Enzo Ferrari

                    Comment


                    • #11
                      Originally posted by Maclin View Post
                      It is not always about HP, larger displacements produce more low end torque. A 7.4 and 5.7 may have same HP rating but completely different torque curve with top HP at noticeably different RPM's. Just saying the 7.4 could probably get it moving and planing sooner.
                      Agree maclin...but who would swap an old carb 7.4 in place of a 350 mpi ? Not I.

                      Comment


                      • #12
                        Me neither. In my last post, "Just saying the 7.4 could probably get it moving and planing sooner" add this "with the 2.0 ratio the mfg installed.", that would more complete my thoughts. I was aiming at the fact that, in my opinion, the boat mfg decided to ask the 5.7 to do what a 7.4 would normally be tasked for in that boat. Only way to make up for the displacement would have been the higher ratio coupled with lower expectations. The owner can "finish" it off and do the ratio change to make up for some of it without an engine swap. The boat needs a bigger engine (or smaller expectations!).
                        _

                        Comment


                        • #13
                          Thanks to all for the excellent discussion on this topic! I'll try to give an update on the performance of the boat and it's history.

                          I bought the boat just in August, being the fourth owner, it is originally equipped as described. There are lots of Montereys 265 CR and 270 CR out there with 5.7L, either Volvos GXi (320 HP) or MAGs MPI (300 HP). Many owners may just cruise between 3.000 and 4.000 rpm, optimum on plane at 3.500 rpm. They might not care about max. rpms nor may have a closer look to manufacturer specs of the engine. Mine should run WOT in the range 4.600 - 5.000 rpm. But the Monterey is a bulky, 'fat' cruiser. I'm not even sure about it's real empty weight. The specs from Monterey are somewhat misleading. I posted the following question on the owners forum, no reply yet:

                          Can someone unveil why the 265 and the 270 Cruisers have a huge empty weight difference, being almost the same boats, at least in terms of overall dimensions. The specs of the 2004 265 shows 6,000 lbs, while the 2005 270 shows 7,400 lbs. If you compare other cruisers of different building years, you won't find such a 'gain of weight'. It looks like 6,000 lbs is empty and 7,400 is loaded weight (might include optional equipment like a generator).

                          But this is not relevant any more.

                          Comment


                          • #14
                            Facts are: Second owner replaced rev gauge by a Mercury gauge (probably for outboards). I noticed that it didn't work so just replaced it by a Faria gauge with hour meter. It shows precisely every 100 rpm (not 200 rpm as many gauges). I did run the boat alone, no fresh water, no grey water, half on fuel, there is no generator nor A/C aboard: Definitely hardly hitting 4.200 rpm at 30 mph, might have been 32 mph.

                            I have a recent screen shot of the diagnostic device showing working hours versus rpm range (until I bought the boat). If this is really correct, this engine never ran over 4.105 rpm in his 339.7 total hours. And just 0.8 h between 4.000 - 4.499 rpm in 13 years!

                            So it seems to be plausible that Monterey did a bad job when powering this model with the 5.7L, gear ratio 2.0:1 and 20p propellers. At least considering boating in choppy to rough sea, instead of on lakes or rivers.

                            Well, still need to check if the engine has a problem as per your comments.

                            Just curious that a sales ad which I found yesterday shows exactly the same mph range with the same boat. Have a look to: http://www.***************/boats/2003...s#.Wcggd-vuKrX

                            And another owner of the same boat complained about getting on plane (here at iboats):
                            http://forums.iboats.com/forum/owner...a-monterey-265

                            Comment


                            • #15
                              Sign up today
                              Full link to sales ad:
                              Sales ad showing http://www.***************/boats/2003...s#.WcgljuvuKrX
                              Cruising Speed: 22 mph
                              Maximum Speed: 32 mph

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