Pros-cons: weight / hp (4-strokes, 60-70 hp).

[bossee]

Hi,<br />I would like to replace my old 2-stroke, a 1991 Suzuki DT65, with something newer. But it must be some outboard that match closely my present engine both regarding hp and preferably also weight.<br /><br />My Suzuki DT65 has 65 hp and weight 238 lb(108 kg). My boat weight 1100 lb (500 kg) or slightly more. Max speed is today 30 knots with 1-2 persons onboard. It is a "Hard Top" boat.<br /><br />I had thought I just could hang a new Suzuki DF70 on my boat to replace my DT65. But now I have started to be hesitant because of the weight penalty the boat will suffer since the DF70 wheight 335 lb (152 kg) but I have seen spec where it say the weight is at least 20 lb (10 kg) more. Compared to my old DT65 I would be driving around with really much more weight back there.<br /><br />So I have started to look for any lighter 4-strokes that would be close in real power to my old 2-stroke. For the moment I prefer not a Johnson or Evinrude.<br />Left seems to be Yamaha F60 and Mercury 60 EFI, both about equal in weight. Yamaha F60, 244 lb=111 kg, Mercury 60 EFI, 248 lb=112 kg.<br />I'm aware that Yamaha F60 has carburators and Mercury 60 EFI has eletronic fuel injection.<br /><br />I would like the better force of a 70-75 Hp 4-stroke but think it might be to heavy. But I'm at the same time concerned a 60 hp 4-stroke will be to weak.<br /><br />I do not want any 2-stroke anymore.<br /><br />Anyone been in same situation and did you select the higher hp and weight or lower hp and weight?<br />What was the result with your boat? Did You regret the selection, and if so why?<br /><br />Thanks,<br />Bo

 

[rickdb1boat]

Re: Pros-cons: weight / hp (4-strokes, 60-70 hp).

Hi Bo,<br />What it the length of your boat and what material? What is the Max. HP rating for your boat? The evinrude/johnsons 4 Strokes are basically suzuki's anyway. If you go with a EFI motor in the 60 HP range, I think you will be happy with the performance. The yam's are also a good choice for reliability, even with the carbs. This all depends on your hull design, as to how it would react to a heavier motor.

 

[bossee]

Re: Pros-cons: weight / hp (4-strokes, 60-70 hp).

Hi Rick!<br /><br />>What it the length of your boat<br />It is 17.7 ft (5.4 meter) long and 7.2 ft (2.2 meter) wide.<br /><br />>and what material? <br />Glasfiber and epoxy.<br /><br />>What is the Max. HP rating for your boat?<br />70 hp.<br /><br />>The evinrude/johnsons 4 Strokes are basically<br />>suzuki's anyway.<br />Yes I have seen at least a Johnson 70 hp 4-stroke<br />that was an exact copy of Suzuki DF70, only<br />diffrence was the color.<br /><br />>If you go with a EFI motor in the 60 HP range,<br />>I think you will be happy with the performance.<br />I think a 60 hp will be enough but I'm not sure.<br />I guess a 60 hp 4-stroke should be as powerful<br />as my present Suzuki DT65, 65 hp. But I know the<br />2-strokes often has close or in some case better<br />power than a 4-stroke. <br /><br />>The yam's are also a good choice for<br />>reliability, even with the carbs. <br />Yes I have read some reviews of the Yamaha F60<br />and it seems to be reasonably powerful and also<br />very quite even at full speed and that is really<br />a big plus since my present Suzuki DT65 at full<br />speed is _very_ load (92 decibel).<br /><br />>This all depends on your hull design, as to how<br />>it would react to a heavier motor.<br />I have a picture of the boat model I<br />have (from some old boat magazine where they<br />tested this boat and several other HT boats).<br />Picture is bad quality but will at least give<br />some idea how it is designed. My own boat is<br />winterized now so I can not take any (good)<br />picture of it.<br /><br />

<br /> <br />/Bo

 

[pine island fred]

Re: Pros-cons: weight / hp (4-strokes, 60-70 hp).

hello bo. i will share my experience. have an old pro line 16 ft ctr cousel with a 50 2 stroke yamaha. small but very heavy boat. ran satisfactorly but wished it had 70 hp. burned a rod bearing so i repowered with a 80 yamaha 4 stroke as 70 hp was not available. motor weighs twice as much,356 as to 189 lbs. yes it sits heavier in the water and wallows at speeds below planing (idel ok). i would do it again. quiet and fuel consumption is (no kidding) at least 2/3 less than the old 2 stroke,although the old 50 was deteroating badly and i didnot realize it to the end. now i rarely go past 2/3 throttle.

 

[bossee]

Re: Pros-cons: weight / hp (4-strokes, 60-70 hp).

Hi ferd-in-cape-coral!<br /><br />>...repowered with a 80 yamaha 4 stroke as 70 hp<br />>was not available. <br />I have noticed Yamaha has a 75 hp, F75(and F90),<br />now that is a sligtly modified F80/F100.<br />It weight even more than a Suzuki DF70 so it<br />will probably be _to heavy_ for my boat.<br /><br />>motor weighs twice as much,356 as to 189 lbs.<br />Yes, I see you where in about same situation as<br />I'm now.<br /><br />>yes it sits heavier in the water and wallows at<br />>speeds below planing (idel ok). <br />I have to "drive" some (3-4) nautical miles in<br />a river system before I reach open water and speed<br />is restricted to 5 knots in the river. So a heavy<br />engine is not good at all in the river. I need<br />at least 14-15 knots before my boat plane. I can<br />drive in the river at idle in 2-3 knots ofcourse<br />but it will then take a while before I reach the<br />open water.<br /><br />>i would do it again. quiet and fuel consumption<br />>is (no kidding) at least 2/3 less than the old <br />>2 stroke,although the old 50 was deteroating<br />>badly and i didnot realize it to the end. now i<br />>rarely go past 2/3 thr <br />I usually "cruise" at 20-25 knots in open water<br />and then a 70-75 hp 4-stroke would be just fine<br />I guess since in plane weight is less of a<br />problem.<br />I'm really tempted on the Suzuki DF70.<br />But at the same time the Yamaha F60 might just<br />be enough for me.<br /><br />Thanks for your advice. I will consider the larger<br />engine alternative since it has many advantages,<br />as you say.<br /><br />/Bo

 

[Trevor]

Re: Pros-cons: weight / hp (4-strokes, 60-70 hp).

honda 50 is the most efficiant motor when it comes to torque and horse power to weight ratio I have lodges that run then on 20 welded alum boats also I just put on on an older 17 K&C thermalglass the boat was a bit heavy for the motor but it worked. Also Right now I am running a Zodiac Pro Open 650 with a pair of 75hp hondas on it this motor is the one I would suggest to you<br />the motor weighs in at 373lbs. on my zodiac when I have both motors running at 3500 revs I can still here my self think and I have a combined fuel burn of just over 6gph for both engins!!!!!<br />Good luck with your next purchase!!!!!

 

[JB]

Re: Pros-cons: weight / hp (4-strokes, 60-70 hp).

Don't overlook the Suzuki/Johnson EFI 4 strokes.<br /><br />As good as the Hondas are, they are carbed.<br /><br />Suzi/Johnny 40s and 50s weigh about 250, and the 60 and 70 weigh about 336.<br /><br />The Suzi DF50 is more efficient and less expensive than the Honda BF50, and the Suzi/Johnny DF70s are not only more efficient and less expensive than the Honda BF75, they are faster.<br /><br />I haven't had experience with the Merc EFI 4 strokes in this range, but I can tell you that EFI civilizes a 4 stroke outboard just as it does an auto.<br /><br />Good luck.

 

[Bear]

Re: Pros-cons: weight / hp (4-strokes, 60-70 hp).

Hi Bo Edstrom!<br /><br />I have a Honda 50 on a 16' (4.85 m) 771 lb (350 kg) boat. I think it is just perfect. On your boat a Honda 50, or a Suzuki 50, will not be powerful enough. 60 or 70 hp? Do you need the extra 10 hp? If it was me I'd go for less weight. But it depends of how you use it, load, speed, skiing etc. <br />Lycka till!

 

[bossee]

Re: Pros-cons: weight / hp (4-strokes, 60-70 hp).

Hi Bear!<br /><br />>On your boat a Honda 50, or a Suzuki 50, will<br />>not be powerful enough. <br />That is correct. It will probably take for ever<br />before my boat plane with anything more than 1-2<br />persons if I would select a 50 hp 4-stroke.<br /><br />>60 or 70 hp? Do you need the extra 10 hp? If it<br />>was me I'd go for less weight. <br />We are usually 2-4 persons in the boat.<br />I hope the efficency of outboards have advanced<br />some from 1991 (when my Suzuki DT65 was made) to<br />present and that a 60 hp 4-stroke like Yamaha F60<br />would match my old engine in performance.<br /><br />>But it depends of how you use it, load,<br />speed, skiing etc. <br />I use it mostly for daytrips on lake Vänern. Load<br />is usually 2-4 persons (once we was 5 in the boat<br />but that would be max).<br />I cruise usually around 20 knots, maybe 25 if<br />water absolutely blank. Max speed 30 knots I use<br />only for fun.<br />I do use a wakeboard but not so much (maybe 10<br />times a year) and for that purpuse a heavy boat<br />is good (better wake) and then a 70 hp 4-stroke<br />would be better.<br /><br />I think I will make an experiment early in season<br />when I have the boat ready for use: I will place<br />an extra 90 lb (40 kg) ballast back in my boat<br />to simulate the extra weight of a Suzuki DF70 and<br />see how the boat behave. If no trouble then I know<br />I can use that outboard if I want.<br /><br />>Lycka till!<br />Tack! (Thanks!)<br />God Jul! (Merry Christmas!)