DF90 Reinforcement and questions

[Seapup]

I have been looking at replacement motors for a few months and decided to go with a used df90 (older heavy version) I was able to purchase locally. Now I need to mount it up.

Instead of running the standard outer transom plates and wedge I am debating using a jackplate. Possible problem with this is it would add extra stress to the transom. I know gazmn has a 10" on his lighter etec 90, not sure if one would be an issue with the heavier df though. ( I am going to use plates on the inside) Advantage is it would take the place of an outer transom plate and wedges and also add the ability of height adjustment. ( I believe the bolts could be aligned to mount the jackplate at an angle like wedges) Hopefully this would give a little clearance for climbing around the larger motor. I am thinking of using a 5" setback, Thoughts?

Jackplate would spread load over back of transom.



The motor is off a center console and comes with a binnacle control.



Is there a practical way to use this? I am thinking keep the separate key/beeper it comes with and buy a flush mount control like victor did.

Also the prop is a 3 blade 13.75x19, I am thinking order the solas amita 4 blade 13.75/15, does this sound right?

Thanks, Alex

[Gazmn]

Actually, I have the inside of transom reinforced, the 10" jack plate [which might be considered much - but I LOVE how much it opened up my rear porch] and wedges.

I have a lot of Stuff on my boat. It's not fast possibly for that reason. I think Highlander also used a jack plate on one of his crafts, can't remember which. I'd be curious to hear his thoughts on it.

For me, I think my E-tec guy installed my motor too low, probably just lined up what holes matched. My jack plate is all the way up and that gets me where I think I need to be.
The Jack plate probably weighs 45#'s
I'm not happy about that, but on the whole, I like what it does for my ride and cockpit... It's like having a dive platform
I also switched the seat hinge to the starboard side to free up the port side entry - made a new porch out of starboard
& cut off the horizontal of the pilot seat to give more room in the cockpit
P.S. The wedge does help keep the nose down.

[Seapup]

Thanks Gazmn, That was what i was hoping to hear about the jackplate. The suzuki cowl is huge and I am having trouble visualizing it on the back when its tilted up compared to the honda. I don't use a helm seat and have a deck which I know wont fit the suzuki.

[Highlander]

Here's my set-up on my 10" jack plate
http://i78.photobucket.com/albums/j95/m ... 010006.jpg

http://i78.photobucket.com/albums/j95/m ... 010004.jpg

http://i78.photobucket.com/albums/j95/m ... 010006.jpg

I mounted the jack plate directly to the transome then installed the wedge kit between the jack plate & the eng.


I went with the flush mount SS control was on sale for 1/2 @ the time I bought it


Hope this helps I am thinking of doing the same with my because of the size of my 75HP Merc

J

[aya16]

Couple things need to be considered here, you may not have thought about. First is the steering linkage, need to see if the Mac steering linkage will reach the motor and work when you place the motor back five inches. One thing that is needed with a larger motor is the ability to disconnect the steering from the engine when sailing, this is much more critical than when using say a 50hp, that bigger engine weighs a lot, and you don't want to have to turn it and the rudders at the same time. Especially with the motor tilted up for sailing, as the heavy motor will flop from one side to the other making steering very hard.

The controller you showed will not work on the console we have, unless you installed it at the top of the console, that would look bad and take away the mounting area for the gps. the remote key is what you need of the setup you have with a teleflex side mount controller.

adding to the transom, although some think you don't have to, would be a good idea I think. I added 3/4 marine plywood in three sections to mine, as well as some metal plates. I drilled two extra holes to mount the plywood and plates, and used a ton of 5200 to glue them in place. My transom seems stiff enough and does not flex at all.

using a jack plate will add stress to the transom, but if you could stiffen the transom up, it would give you extra space for tilt and trim.

There are trade offs when putting a larger motor on the mac, there are little problems that need to be overcome, like making sure the quick disconnect works with the larger motor, like I said this is a must when sailing and we have a larger motor. As far as the prop, I would try what you have before you start buying more props.
I'm slinging a 15 inch prop now, started with a 13. No telling what your engine needs till you try it.


here you see my 115 installed, with a few little mod's here and there it will disconnect for sailing as well as stay upright when tilted up for sailing. Does not move and the rudders swing the full lock to lock and doesn't hit the prop if the motor is tilted down. Room to get by into the cockpit is a bit tight, but can be done.

[Seapup]

Thanks for the pics. Flushmount control looks great. For jackplate I am thinking 5-6" will do what I want without too much additional stress.

First is the steering linkage

I had not thought about disconnecting the motor while sailing, one more thing. Currently my disconnect is under the deck so will have to come up with something else. I think the steering will fit with a 6" setback, time will tell. Gazmn did you have to change much with the 10"?

The controller you showed will not work on the console we have, unless you installed it at the top of the console, that would look bad and take away the mounting area for the gps. the remote key is what you need of the setup you have with a teleflex side mount controller.

I was trying to think of some redneck way of mounting it in a box to the top side of the pedestal, but I doubt I would ever be happy with it. I am watching a flushmount on ebay, don't anyone bid against me on it

adding to the transom, although some think you don't have to, would be a good idea I think. I added 3/4 marine plywood in three sections to mine, as well as some metal plates. I drilled two extra holes to mount the plywood and plates, and used a ton of 5200 to glue them in place. My transom seems stiff enough and does not flex at all.

I was not planning on adding extra wood, but am not opposed either. I am debating going with a short inside bar or running one the whole width to the rudders. Do you have any pictures of the wood you added? I am assuming it is sandwiched between the metal plates and hull.

I may give the prop a try, but at 19 pitch know it won't be great. I figure put it on ebay with the extra controls.

[Gazmn]

First is the steering linkage
I had not thought about disconnecting the motor while sailing, one more thing. Currently my disconnect is under the deck so will have to come up with something else. I think the steering will fit with a 6" setback, time will tell. Gazmn did you have to change much with the 10"?

Yeah; I had to have ~7"s of a SS bar added to my steering arm

[aya16]

sorry no pix at this time, but all I did was take some paper below and cut it to the size I needed for the wood, found later after I cut the 3/4 inch plywood, it was much easier to install in three sections, glued (5200) and bolted the two sides in, then the middle (where the motor bolts up) Then used 1/8 thick 4 inch wide metal to tie it all together all the way across, then bolted the motor to all that. Probably over kill, but it worked. (the two side pieces needed to be like 1 1/4 thick to be even with the 3/4 Middle piece. Because of the motor well) Then it was simple to put the metal strap in.

I made a mistake when I read the prop you had, yeah the 19 wont cut it. Yeah the farther back your engine sits the longer your steering linkage will have to be to line up straight with the rudders. These are the little problems we run into with any mod we do, there seems to always be some little glitch that has to be fixed.

Look into BWY for the quick disconnect they sell, by having the rod that attaches to the motor (from bwy) extended to what you would need????? might work. be careful here, measure perfect, to get the rudders and engine working together instead of fighting each other. That's a large angle you have to deal with too.
Maybe have to come up with another solution. Not sure it will work well. The steering rod will pull alright, not sure it will be ok when it pushes the motor.

[davidbourne]

Very interesting!

@Highlander, I'm intrigued that you want to put a jack plate on you 26M. It *would* be nice to gain a few inches of space in the M's narrower outboard well.

What do yo think this will do to sailing and motoring performance? I know these jacks are supposed to be good for motoring, but I can't remember why.

I'm interested in having more space to climb through, especially since I plan to get a Suzuki DF90 soon.

@Gazman, I'm curious what you think about performance. You said it helps bring the bow down. Did you ever have an engine without the jack?

Thanks,

DB

[Gazmn]

What I meant was the wedges[ along with a dole fin] help to keep the bow down when the motor is fully tucked in. Sorry will get back to you regarding sailing effect [ I'm a lousy sailor ] I like that my motor is so high out of the water while moored, room to pass through or swim from transom & motoring is a pleasure.

Did you ever have an engine without the jack?

Yes. I can only say that it improved things [ having the JP]- as much as I had been looking to make sure it didn't make things worse. Things are better - I just can't quantify how much better.

[Seapup]

Yeah; I had to have ~7"s of a SS bar added to my steering arm

Cool, thanks.

These are the little problems we run into with any mod we do, there seems to always be some little glitch that has to be fixed.

Yeah, Part of the fun I guess

I already have the quick disconnect, once I get the motor bolted up will go from there.

I stopped by today and dropped off a deposit for the motor, so its official.

I also ordered a jackplate. Went with a MJ5 jackplate since I was able to get it used. It can be set to 2.5",5" or 5.5 with 6 degree wedge angle so I shouldn't need wedges. I am thinking the 5.5" will work well without too much extra stress. It weighs 19lbs and spreads the load on the transom on two 5x12 surfaces. I am figuring it cost me the same as the two aluminum outside plates and wedges would have cost me otherwise. I doubt it will give any performance but maybe add a little room in the back and let me tune the height a bit. http://www.bobsmachine.com/News/1944-release.pdf



I have a couple pieces of aluminum channel that are 3/8" thick and 2"x6"x48", I am thinking use one for inside the transom then just get some plain stock for inside the motorwell.

[Gazmn]

I'm on my way down to Marathon, FL from NY. And <50 miles into the trip, the steering arm that connects to the motor broke

The very same part I was telling you about

Are the any Mac friendly shops enroute of I 95 South???

[Seapup]

Little update. Put the honda on craigslist last week and sold it in one day which was convenient. Yesterday afternoon the new owner and I took it off which went smoothly. Today I went to work making the plates and mounting the jackplate. I debated drilling new holes in the transom and mounting the plate below the lip to make things easy, but finally went to work grinding until it fit the lip snugly. The inside plates were pretty straightforward, toughest part was removing and reinstalling the motor well drain hose. Depending on the weather I should be able to mount the suzuki up sometime next week.

Fitting the exterior plates to the transom lip.




Load spread out over the transom.



Upper inside plate.

[Seapup]

I think the jack plate should work out pretty well. You can set it to 2.5" or 5" of setback. I am going to start with the 5". You can also angle it pretty much anyway you want. I have it set up so it is 5" back at the top and 4" at the bottom, so equal to about a 1" wedge for some additional trim. Also since I didn't figure I would need 4" of rise. I have the backing plates mounted to allow me to raise the motor up 2" or drop it down 2" from where my honda was mounted.




The mailman dropped off a solas 4 blade prop today, 13.75x15, it is next to the 11.8x9 honda which I was using.



Also I ordered a used set of flushmont controls off ebay which should arrive next week sometime. While I am mounting the controls I am planning on adding a spacer under the pedestal and mounting it about 4" higher so it is more comfortable while standing. Anyone move one up before and find it better or worse?

[davidbourne]

Seapup, thanks for your updates on this project.

I looked at the jack plate manufacturer's pdf document and it finally answered for me *why* a jack plate is supposed to help improve performance. Here is the quote...

"Use of the 5" offset and the 6-degree wedge together positions the
engine 5-1/2" behind the transom into clean water and away from
bubbles and hull turbulence. This helps to stop prop slippage and
improves steering."

This makes sense, and it does not imply that any "stern lift" would be caused by a jack plate.

I mention stern lift because it is strongly cautioned against in the 26M manual (and I assume the 26x manual ?)....

"DON’T INSTALL LIFTING HYDROFOILS ON YOUR OUTBOARD MOTOR. They are designed to lift the stern when powering. They also contribute to instability. The benefits are not worth the risk."

Hydrofoils would also increase the risk that the water ballast might not empty all the way since the bow could be pushed too low at higher speeds.

But a jack plate should not do any stern lifting. If anything, it might raise the bow a bit by moving the motor weight back a few inches. But then again, maybe the 6 degree wedge effect counters this.

I'm still not sure if I should try a jack plate or not on my new M. It's pretty new ground. But I'm glad you are trying it! Good luck with it.