Ultrex Built-In Transducer Modification

[straffordengineer]

I have a 2020 Ultrex that came with a built-in Hummingbird MEGA transducer. I bought the trolling motor used (like new) for $1400 so I couldn't be picky about the transducer. Unfortunately, I don't use Hummingbird chart plotters. I have a Garmin 106sv. Obviously, I can't use the built-in transducer in the trolling motor with my chart plotter and because of the size and shape of the built-in transducer, I cannot mount my Garmin GT54 transducer to the trolling motor. I am thinking about replacing the front nose of my trolling motor with a standard US2 transducer nose cone (minn kota p/n 9421-287). I would prefer just to have an empty nose cone as I don't plan on using the US2 transducer but Minn Kota only sells them with transducers. I just need a nose cone to get rid of the Hummingbird MEGA transducer.

I have never had an Ultrex apart but I assume it comes apart just like an older Power Drive Minn Kota trolling motor, just slightlly larger in diameter. It appears from the illustrated parts list that standard US2 nose cone (p/n 9421-287) attaches to the trolling motor head in the same manner as the Hummingbird MEGA transducer nose cone (2 through bolts, washers, gasket, seals, etc). However, the illustrated parts list also mentions something about a M SKU and the 9421-287 part is one of the parts that indicate NOT FOR M SKU. I could purchase the entire motor/tube assembly with the needed US2 nose cone but it is cost prohibitive. I can purchase the US2 nose cone and the needed gaskets for around $100. The complete motor/tube assembly would be about 4 times that much. It appears from the illustrated parts list that you can simply unbolt the existing MEGA transducer nose, remove the MEGA cable from the tube, thread the US2 cable up the tube, and attach the US2 nose cone in the same manner of the previous nose cone. Using new gaskets and seals of course.

Has anyone ever done this or has anyone had an Ultex apart and could provide some guidance if what I am proposing is possible? I tried contacting Minn Kota but they were no help. They would not support any non-standard modifications to the trolling motor.

[Wayne P.]

If the motor has the MDI transducer, Transducer Shield and Saver has a block that fits between the prop and transducer to create a flat surface so you can attach the GT54. Contact them if that is what you have.

[straffordengineer]

If the motor has the MDI transducer, Transducer Shield and Saver has a block that fits between the prop and transducer to create a flat surface so you can attach the GT54. Contact them if that is what you have.

I have the MDI transducer. I looked on the site you mentioned. I did not see what you are talking about. There is only about 3 inches of clearance behind the MDI transmitter. I don' see how it would work.

[Wayne P.]

I have the MDI transducer. I looked on the site you mentioned. I did not see what you are talking about. There is only about 3 inches of clearance behind the MDI transmitter. I don' see how it would work.

There was an example with the Lowrance Side Scan transducer on their site. CALL and explain your need.

[straffordengineer]

If the motor has the MDI transducer, Transducer Shield and Saver has a block that fits between the prop and transducer to create a flat surface so you can attach the GT54. Contact them if that is what you have.

I received a response back from Transducer Shield and Saver. It doesn't sound like anything I am interested in. The complete set-up will cost almost $200. $110 for the Garmin transducer bracket and $72 for the "filler" to go over the MDI transducer. Parts alone will be $182 plus about $15 in shipping costs. They have no pics of what it would look like. I have my doubts if it will work and it will stick so far below the trolling motor it will probably get damaged. There has to be a better way. I am still leaning towards replacing the nose cone with a standard US2 transducer.

[fishnfireman]

It appears from the illustrated parts list that you can simply unbolt the existing MEGA transducer nose, remove the MEGA cable from the tube, thread the US2 cable up the tube, and attach the US2 nose cone in the same manner of the previous nose cone. Using new gaskets and seals of course.

I replaced a US2 nose cone with a MDI a couple of years ago. Was under the impression they won't sell a nose piece by itself anymore.
If they do It's not that hard to change them. Matter of fact if your not going to use the US2 you could just cut the wire and not have to feed it thru the shaft.

[Fishshooter]

I received a response back from Transducer Shield and Saver. It doesn't sound like anything I am interested in. The complete set-up will cost almost $200. $110 for the Garmin transducer bracket and $72 for the "filler" to go over the MDI transducer. Parts alone will be $182 plus about $15 in shipping costs. They have no pics of what it would look like. I have my doubts if it will work and it will stick so far below the trolling motor it will probably get damaged. There has to be a better way. I am still leaning towards replacing the nose cone with a standard US2 transducer.

Sent you a pm.

[DiawaKid]

I thought you can buy adapter cable for these built in transducers to plug up to other units.

[Wayne P.]

I thought you can buy adapter cable for these built in transducers to plug up to other units.

The Minnkota 83/200 kHz US2 transducer is adaptable for several brands.

The Built-in MEGA DI (MDI) and Built-in MEGA SI (MSI) transducers only work with Humminbird units.

[straffordengineer]

I replaced a US2 nose cone with a MDI a couple of years ago. Was under the impression they won't sell a nose piece by itself anymore.
If they do It's not that hard to change them. Matter of fact if your not going to use the US2 you could just cut the wire and not have to feed it thru the shaft.

you can’t buy the Hummingbird transducer nose cones separately but you can buy the standard US2 nose cone. $87.

[Mike2718]

Not sure if this will help. Here are some links to a multi-video series how to tear down & reassemble an Ultrex. He shows how the transducer and wires are attached in one of the videos, I just don’t remember which video. A couple of the videos are a little long but you can scroll through them. You will be able to tell when it gets to the part about the transducer.

[straffordengineer]

Not sure if this will help. Here are some links to a multi-video series how to tear down & reassemble an Ultrex. He shows how the transducer and wires are attached in one of the videos, I just don’t remember which video. A couple of the videos are a little long but you can scroll through them. You will be able to tell when it gets to the part about the transducer

Thanks, these videos were very helpful.

[mrsturggie]

Try contacting jones trolling mtr and see if they may have a nose cone lying around for a fortrex along with necessary gaskets and seals.

[straffordengineer]

I replaced a US2 nose cone with a MDI a couple of years ago. Was under the impression they won't sell a nose piece by itself anymore.
If they do It's not that hard to change them. Matter of fact if your not going to use the US2 you could just cut the wire and not have to feed it thru the shaft.

Mike, I also identified just a plain nose cone without a transducer for a 4" motor Terrova (421-276). The illustrated parts list indicates a 9421-287 or a 421-276 fit the 4" Terrova so since the 9421-287 indicates it fits the Ultrex, it stands to reason the 421-276 should also fit the Ultrex. It is only $12. The US2 nose is $87. I can always purchase the 9421-287 later if the 421-276 doesn't fit.

[Mike2718]

Mike, I also identified just a plain nose cone without a transducer for a 4" motor Terrova (421-276). The illustrated parts list indicates a 9421-287 or a 421-276 fit the 4" Terrova so since the 9421-287 indicates it fits the Ultrex, it stands to reason the 421-276 should also fit the Ultrex. It is only $12. The US2 nose is $87. I can always purchase the 9421-287 later if the 421-276 doesn't fit.

That sure seems like it’s worth a shot. If it works, that will definitely be a very cheap solution. The only possible issue I can think of may be the bolt lengths. I’m not sure if that nose cone would affect the length of the bolts you would need.
Hope it works.
Good Luck