Engine size help

[jahoward1]

Hey everyone,

You guys, along with THT have been alot of help.  Anyway, I have a 1997 Osprey 200 CC equipped with a 115hp Johnson outboard.  The boat moves about 33mph-35mph at about 4500 rpm.  I would like to do over 40mph.  

The hull plate is very worn and impossible to read.  I was wondering, what is the max recommended engine size for my boat.  Also, does it make a difference for speed and safety if the outboard is a 2-stroke or a 4-stroke since the 4-stroke looks bigger?  I'm looking at a few things, including trim tabs so I probably won't change anything until next year but something will change.  Thanks again Aquasport owners.

James H :afro:

[scott_gunn]

I have the same hull, but from 87. The max rated hp on mine is 185. I have a 150 and can do 43-44 mph.

[jahoward1]

Thanks Scott-Gunn.  Does it matter whether it's a 2-stroke or 4-stroke?  The 4-stroke looks bigger and heavier.

[MarshMarlowe196]

4 stroke is typically heavier, but it's not quite as heavy as a lot of 2 stroke fans make them out to be.  They're about 30% heavier than their 2 stroke counterparts, generally speaking.  You should be able to get close to 40mph WOT with that 115 and the right prop.  Are you looking to cruise @ 40mph?  If so, you'd probably need at least a 175hp outboard.

I can cruise around 35mph @5K RPM's in my 19-6 (same hull as 200 Osprey) w/ my 140HP.

[RickK]

4 stroke is typically heavier, but it's not quite as heavy as a lot of 2 stroke fans make them out to be.  They're about 30% heavier than their 2 stroke counterparts, generally speaking.

Doesn't sound like much when you put it that way but a 115 Johnson weighs about 320lbs and the 115 4-stroke weighs 420lbs     On a 170 that is a lot of extra weight - now if your putting that on a 200 then that's a different story.

[MarshMarlowe196]

Yes, the difference between those two motors is a lot, but sometimes it depends on what you're comparing.  In this case, there's a substantial difference in weight.  In other cases, like comparing 90 HP 2s and 4s, a 90HP Suzy only weighs 20lbs more than an ETEC.  My 140 weighs less than a Suzy 115... ??  

My boat does feel pretty fat in the rear since I got the 4stroker (Hence "badonquasport"  :)   ), but I've just added scuppers and enjoyed not buying oil, so I'm ok with it.  Doesn't really seem to affect the performance of the ride at all, but it will affect your draft.  I went from floating in approximately 8-9" of water w/ the 2s 90HP to right at a foot now with the 4s.

[Aswaff400]

i've seen almost 43 mph on mine going with a 15 knt wind and in a 1 ft chop, trimmed out and just under 6,000 rpm...

the rating on the '97 is 150 hp... i believe it can handle more though... i planned on putting a 200 merc on the back of mine at the end of the summer... i have the itch to have a WOT above 50 mph... but still cruise well at 35...

that was until my truck decided to cough up a nice chunk of a cylinder and the tranny let go... something about computer chips and rev-limiters ...

[LilRichard]

Badon has it right - weight differences are disparate at different HPs.  For example, I think my Suzi 150 only weighs ~60 lbs more than a 150 Optimax... so for me it was worth it.  This is my first four stroke outboard, and I think it is the way to go now.

[jahoward1]

Thanks everybody for the replies.  I've been looking at some used 150hp Evinrude and Johnsons (only because I have a Johnson now) but one more question.  The part of the hull plate that I can read states that the max weight is 870lbs.  Will a heavier motor change that number?  This is only my second year with this boat and I love her   but I can now see why people like larger boats with more powerful motors.  Thanks again.

James H :afro:

[MarshMarlowe196]

I have a 150HP for sale!  

viewtopic.php?f=6&t=4312

Yea... a heavier motor would have to be factored into that.  What's kind of confusing about these boats is that it seems the overall weight and max HP rating went up over the years.  I'm guessing that in the later (genmar) aquasport years, the transom changed from 20" to 25" (might be wrong) making it stronger and thus more capable of supporting the weight of a heavier, more powerful engine.  Just speculation on my part though.

Those ratings are probably underrated though; most likely to protect Aquasport from any incidents caused by overloading or hanging more HP on the boat.  I think the 19-6 (200), in any year, is safely capable of accomodating up to 200HP if it's still structurally sound.  Your insurance company will disagree though  

[Aswaff400]

I have a 150HP for sale!  

What's kind of confusing about these boats is that it seems the overall weight and max HP rating went up over the years.  I'm guessing that in the later (genmar) aquasport years, the transom changed from 20" to 25" (might be wrong) making it stronger and thus more capable of supporting the weight of a heavier, more powerful engine.  Just speculation on my part though.

Those ratings are probably underrated though; most likely to protect Aquasport from any incidents caused by overloading or hanging more HP on the boat.  I think the 19-6 (200), in any year, is safely capable of accomodating up to 200HP if it's still structurally sound.  Your insurance company will disagree though  

actually seems like they went up, late 80's where i believe 185 hp, but '94 (guesstimating) and newer are rated lower at only 150 with a 25" transom WTF man! lol oh well im still bolting up a 200 merc :batman: ... that is after i fix everything in my last post! haha

[MarshMarlowe196]

that was until my truck decided to cough up a nice chunk of a cylinder and the tranny let go... something about computer chips and rev-limiters ...

I don't think it was a computer chip or rev-limiter; the problems were most likely caused by that blue oval in the grill    .  

Just kidding, I'm actually looking to replace my red machine with a Ford Truck like yours.  Good luck-

[Aswaff400]

that was until my truck decided to cough up a nice chunk of a cylinder and the tranny let go... something about computer chips and rev-limiters ...

I don't think it was a computer chip or rev-limiter; the problems were most likely caused by that blue oval in the grill    .  

Just kidding, I'm actually looking to replace my red machine with a Ford Truck like yours.  Good luck-

it was a mix of towing a 11K lb trailer and holding the pedal on the floor in a mud hole afterwords... truck still runs though, but not too good... gets me to work and back(2 miles)   i actually am buying a 302 block to rebuild on friday... 306? or 347 stroker? oh the choices  :colors:

[john saco]

I'm a newbe with a 1975 19-6. I'm looking for an engine. My concern is will a 115 or 150 4 stroke weight drop the self bailing drain holes under the waterline? I spoke to a guy yesterday on the water that has a 19-6 with a 140 Susi 2 stroke. He says the drain holes are partly wnderwater so it doesn't self bail. I don't want to refit my boat and put it in the water and have the drain holes under water. Can anyone help with some advise?
John

[Anonymous]

John,
I put a 140 4 stroke Suzuki on my 1976 19-6 last year, and it is a dream. The boat sits a little lower in the water but it still self bails. This motor and size was recommended to me by Tommy of Hammerhead. Good luck.
Katherine