Jet drive ??"s

[BigTerp]

Need a little schooling on jet drives. My buddy just got a 1994 50/35 Johnson jet drive that needs a rebuild. He plans to do the work himself so we can use it on my boat (what a friend!!). I have a 1996 Tracker Sportsman 1648 flatbottom. Other than it's a short shaft, I don't know anything else about the motor other than the size and model year, he just picked it up the other day and I haven't had the chance to look it over. What things do I need to consider with the combination of this motor and my boat? Will it even work well on a 16' flatbottom? I'd like to stay away from any transom or other modifications. Any advice/tips/things to look out for, etc. are greatly appreciated!!!!

 

[smackdaddy53]

You will probably need a manual jack plate to raise the motor. The front of the jet foot needs to be close to flush with the bottom of the boat.

 

[lowe1648]

Depending on the height of your transom 15" or 20" a short shaft obj needs a 22" transom. I know with my Yamaha i would be able to bolt it onto a 20" and make it work without a transom riser. If you look at obj website they have all the info you need for setting it up

 

[BigTerp]

Thanks for the quick replies. I have a 15" transom. I'll check out Johnson's website and see what knowledge I can gain.

So I'd probably have to gain 5-7 inches of transom height to make it work? Do jack plates provide that much?

What about motor weight? Any issues with it making me stern heavy?

How about performance with a flatbottom? I've read jet drives do better with tunnel hulls.

 

[BigTerp]

Depending on the height of your transom 15" or 20" a short shaft obj needs a 22" transom. I know with my Yamaha i would be able to bolt it onto a 20" and make it work without a transom riser. If you look at obj website they have all the info you need for setting it up

I checked out Johnson's website, but couldn't find much. Maybe your referring to a different website?

 

[shallowminedid]

60 40s are light so weight shouldnt be an issue. jack plates usually raise motor 6 inches up. and it https://www.outboardjets.com they do do better with tunnels but u dont need one a tunnel just lets u get in 2 inches of water without worryin about ur foot

 

[Lil' Blue Rude]

You won't have to worry about weight I had the same motor on my 16' 42" flat bottom. Just swapped it for a 60/40 evinrude. It will do fine on a flat bottom. Biggest diffrence with the tunnel is you gain a little more clearance compared to a flat bottom. Youd gain more clearance from the tunnel if your boat was a semi v. Speed should be better with the flat bottom. Alot of people have these motors on 17' 52" around here so it'll push you fine.
Good strong motor. I know I loved mine but I wanted to go faster so I moved on to bigger and better.

 

[BigTerp]

Thanks for all the responses!!

After checking out OBJ and listening to you guys, it's definitely doable. Just going to depend on how much work is involved in getting the motor back in shape.

Also throwing around options for tiller vs. stick steer. I'm planning on removing my middle bench and installing a pin mounted seat and extending the front deck just a bit. I use this boat alot for waterfowl hunting and am trying to keep an open floor plan for gear and easier/safer navigation throughout the boat with heavy waders on and freezing temperatures. So right now I'm leaning towards converting this thing to a tiller (if possible) to keep things nice and open, it's currently setup for controls.

 

[shallowminedid]

something u may not know is if the jet foot is not set close to perfect it will also send a spray into the boat. not fun with tillers. or add a splash plate

 

[BigTerp]

How exactly should the foot be set? From what I've read it sounds like the front of the foot should level with the bottom of the boat. Not sure about trim though.

 

[shallowminedid]

the lowest part of my foot is level with my hull.mine is like an inch higher than most. my theory to setting the height... keep raising it till it slips. when i had the leading edge level i had spray goin 10 feet in the air from hitting the front of the jet pump and spraying straight up. most people add a splash plate from the hull to the foot to eliminate that. or a tunnel does too. and i think if ur jackplate has a set back that makes it worse

 

[smackdaddy53]

How exactly should the foot be set? From what I've read it sounds like the front of the foot should level with the bottom of the boat. Not sure about trim though.

Read #6
https://www.outboardjets.com/catalog/ownersmanual/Owners%20Manual.pdf

 

[BigTerp]

Thanks. That makes pretty good sense.

How do you guys feel about homemade jack plates?

 

[cva34]

How exactly should the foot be set? From what I've read it sounds like the front of the foot should level with the bottom of the boat. Not sure about trim though.

Read #6
https://www.outboardjets.com/catalog/ownersmanual/Owners%20Manual.pdf

Thanks Smack thats some of the best info I have seen...I do not own or do I plan to.Just don't need to run that shallow ...But knowledge always comes in handy...cva34

 

[smackdaddy53]

Thanks. That makes pretty good sense.

How do you guys feel about homemade jack plates?

Im going to fabricate one out of 3/8"x3"x3" aluminum angle. I had a bobs manual jack plate i was going to pick up from a guy but he stood me up three times. $50 for a $200 JP but i guess it was too good to be true. Now i have to reverse a paypal payment.

 

[cva34]

Thanks. That makes pretty good sense.

How do you guys feel about homemade jack plates?

Im going to fabricate one out of 3/8"x3"x3" aluminum angle. I had a bobs manual jack plate i was going to pick up from a guy but he stood me up three times. $50 for a $200 JP but i guess it was too good to be true. Now i have to reverse a paypal payment.

Me feel fine about homemade! Just thought what about a old /broken Hyd one 'cause What most most manual are is a SS all thread bolt replaceing the Ram..Should be a easy mod. and maybe cheap.The other thought well ? how much set back can you stand? ..cva34

 

[BigTerp]

Thanks. That makes pretty good sense.

How do you guys feel about homemade jack plates?

Im going to fabricate one out of 3/8"x3"x3" aluminum angle. I had a bobs manual jack plate i was going to pick up from a guy but he stood me up three times. $50 for a $200 JP but i guess it was too good to be true. Now i have to reverse a paypal payment.

I've been checking out some plans that uses 1/4" aluminum angle. I'm thinking of a manual model with as little setback as possible. What kind of angle are you guys using 6061 or 6063?

 

[BigTerp]

After doing some more research I'm at a loss on what is the best way to fit this motor to my boat. Jack plate, or some sort of transom riser. Going to have to raise the motor 5-6" and I'm guessing the motor weighs roughly 200#. I replaced the transom wood this past september, so I know it's in good shape. Just concerned a jack plate will put more stress on my transom than a transom riser. But I like the thought of a manual jack plate for the ability to fine tune the motor height. Thoughts?

 

[Lil' Blue Rude]

I'd go with a transom riser myself. But that's just me. You can always slot the mounting holes on the motors tilt trim bracket to make fine adjustments. Little bit of fine tuning can make a big diffrence in perfomance.

 

[BigTerp]

I'd go with a transom riser myself. But that's just me. You can always slot the mounting holes on the motors tilt trim bracket to make fine adjustments. Little bit of fine tuning can make a big diffrence in perfomance.

Thanks. The fine tuning aspect is why I think a manual jack plate would be better. Plus I can re-power easier down the road. Probably going to end up going the jack plate route. Thanks for all the suggestions!!