Re-power 1997 245 Osprey thoughts

[thomasjames]

Appreciate thoughts on using 2015 115hp  Yamaha 4 stroke twins -- they currently spec out at 128hp which round figures 260 hp.
She previously had an orginal 225 Evinrude which now rest with a rod through the block --
The idea is a bit more hp but also the benefit of redundancy with better fuel economy.
Input greatly appreciated --

[RickK]

That would be cool,with a lot of thought going into it.
You have to look at the notch in the transom and know that you'll have to widen that to keep a pair at .. probably 20" outboards.

[wingtime]

Going from a single to twins requires filling in the cutout or notch in the transom.  You want the engines higher not lower.

Those four stroke 115 are not going to have the torque though. You have to consider the torque more than the HP. Also you will have the additional drag of another lower unit so in reality you really have 260 hp.  If I was going to go thru that much trouble of converting to twins I'd go with 150s. 

Something to consider... A single 250 Etec (Gen1) will connect directly  up to your existing rigging and wire harness.

[thomasjames]

I don't understand "fill in the notch"? The motors have 25" shafts as did the 225 Evinrude would sit at the same height by just repositioning the height of the bolts the boat was originally set up for either single or dual motors so the cavity plates are easily positioned on either side of the keel -- in 1997 no single 300hp available so the 150 dual option was the way to go --  actually was going to set them on jack plates about 5-8" offset -- though adds an extra 2k to the deal --
The newer since 2014 Yam 115 increased displacement 1741 to 1832 coupled with a DOHC head increase for better intake exhaust resulting  in more mid- range torque and increased WOT from 5-6K to 5.3-6.3 K -- nice with 87 octane ethanol proof
Do appreciate your thoughts --

[Capt. Bob]

I don't understand "fill in the notch"?

Maybe they're referring to this statement from SeaBob, a former Aquasport rigger.

Now, on the later versions, the 225/245/250 Explorers/Ospreys, twins required "alterations" from single installs.  On the 225, the steering cylinder was a transom mount, as there was no way to accomodate the front mount cylinder with out it hitting the sides of the splashwell before it reached hardover.   On the 245/250, a "relief" was molded into the swim platform, starboard side (ever notice that little 3-4" dip just adjacent to the splashwell?) to allow clearance for the front mount cylinder to swing all the way hardover.

Here's a little more on the subject.

https://classicaquasport.com/smf/index.php?topic=9807.msg84971#msg84971

Good luck.

[thomasjames]

Thanks Captain for the insight -- yep cut out in place as noted -- seastar will work fine with a slave --

[wingtime]

I'm referring to  the dip in the center of the transom not the notch for the steering cylinder. All 225/245/250 Explorers and Ospreys came out of the mold with a straight across transom top. Another words the top edge of the transom is totally flat, straight and level running side to side from each side of the swim platform. On boats rigged with twin engines the top edge of the transom is covered with two overlapping aluminum angles and the motors are drilled and mounted (25" shaft motors). On single engine powered boats a template is layed on the top edge of the transom and a 3-4" down dip is cut into the transom top. Then the raw top is covered by both aluminum angles on the straight sections and white plastic trim on the curved sections. They had to do this because the height of the transom is higher in the center than further out where the twin motors would be located.  If they didn't cut the dip into the center of the transom they would have to use 30" shaft motors instead of 25".  Later production boats made in 2002 & up did away with the dip and singles went to 30" shafts.

[thomasjames]

Ok got yeah Wingtime -- decided rto use Atlas micro jack plates which will eliminate having to deal with a few headaches --
Thank you very much for the input -- TJ

[thomasjames]

Let me know if better to start a new topic though this is in the same vein as the original post

As mentioned going to use jack plates to compensate for the transom cut out --

Question is 4" or 6" == yeah 2" isn't significant I am thinking, though would  appreciated some opinions and thoughts

Thanks

 

[RickK]

Keep it in this topic - it's all related.
Remember that the designers planned the Euro transom with the proper setback for the Center Of Gravity (COG) of the boat with fuel tank, center console, forward weight of the boat in general, in mind.
That being said, they didn't try to shorten or lengthen the offset based on one or 2 motors and that is a lot of weight difference on the same offset.
Will 6" more setback matter on this boat with a single?  Probably not.  Maybe a little with twins - my jackplate weighs 40 lbs - so x2 is a lot of weight in itself.

[thomasjames]

You have a good point RickK--

Thinking though 4-6" offset shouldn't have much effect one way or the other in regards to weight distribution or transom ability to handle it.
Since the reason for the jack plate is to compensate for the cut out and to make mounting easier and height adjustment more precise then a 4" would be adequate -- ??? 

[RickK]

Do you have hydraulic steering tubes in the front of the engines? I have a Seastar tube on the front of mine and for my jackplate I needed to compensate for the hydraulic lines and where they attach. If I didn't, when you tilt up the engine all the way it could snap off the hydraulic lines on the transom.  That being said, I added a powerpole mount that added 1/2" and then had to add 2" aluminum spacers to set the engine back about 8".

[thomasjames]

It will be above the transom when mounted we roughly estimated no problem with BayStar cylinder when engines are tilted --
your jack plate appears flush with the transom -- we need to raise the motors since they are now offset from center line --
We will do a little more checking --

[RickK]

Yeah, I had to buy a jackplate because my lower bolt pattern of the engine mount landed right at the floor level - DOH!!

[enijjer]

I realize this is an old thread but thought this might be a good place to capture the discussion on the question I want to ask.

Any thoughts on why RickK's comment (Quoted below) wouldn't work? Since you would switch to 20" motors wouldn't that bring the cavitation plate up in relation to the keel?

Seems that a transom not notched with 25" motors would be equivalent to transom with a 5" deep notch and a 20" motor. Although my transom is only notched about 2.5" but I think there is room to make the notch deeper.

I my mind this seems to make sense and would be a lot easier than trying to build the transom back up and making it structural. Also since you would be using 20" motors there would be a little less weight on the back of the boat.

I am tossing around the idea of switching to twins from a single on my 245 do if any one has some advice I am all ears. I have a 1995 245 Osprey.

Thanks,

Erro

That would be cool,with a lot of thought going into it.
You have to look at the notch in the transom and know that you'll have to widen that to keep a pair at .. probably 20" outboards.