In my opinion. When you take your boat to a shop to have it worked on the first thing they do is look at your prop shaft.

They are seeing if they can get you to file a claim and they shop make all the money off the repair, cuz they do the repair at full book rate.

You can have the insurance pay you directly and shop around for a shop that will do the replacement at a good deal for you, and you the boat owner comes out with a little money in your pocket versus the repair shop making all the money

Or option 2 you can get your prop shaft straigthen, I have seen this option work many times with no future problems

I got it fixed about a month ago covered under merc warranty. Having error codes on the power head now.

Let me give u some advice on sei I have one shaft did same thing they replaced it in 7 days. I went threw four lower units since december two I paid out of my pocket one factory and one sei. Two was refurbished from factory they both came apart they have no warranty paid $2500. A new one cost alot more. Sei has problems but they have life time warranty. And has never been a problem with sending u another one. Now I have one in box in my boat shed and one on my motor merc 225. Pay $800 or $4000 go figure

I have had my SEI lower unit for about 4 months now. So far(knock on wood) no problems. Time will tell.

I have had close to the same experience as bigbass with OE vs SEI. I am on lower unit number 6 on my own boat. Progressive insurance paid for 4 OE at $3500 ea. Jackknifed the boat, truck and trailer in a massive storm on the I20 humps and bumps between Forney and Mesquite a few years back. Progressive and I parted company on that boat and I bought it back for next to nothing after they totaled it. No more insurance. So, when lower unit number 5 got destroyed by a Lake Fork Stump that failed to yield to the right way and HIT my prop and destroyed my lower unit I had to pay out of pocket. I sell them all and make more on the reman and OE but prefer to sell the SEI. Simple math to me. Take $845 for an SEI lower and buy another SEI lower for $845 for back up and buy a new prop for back up for $600. Assume that the lower blows and prop creates a new mini brush pile on Fork. Put the spare lower on and the spare prop. Bust out a calculator and silently smile to yourself when you realize you are still ahead by $1210 (based on $3500 for OE). Send SEI the lower unit you destroyed and you are out $50-60 shipping to them. You get a "rebuilt" SEI back. Sell it as used for $200 or more on here or Craigslist.Now you are ahead another $150 or more (less the warranty return shipping).

I'll admit when they first came out I and everyone else thought they would crack like an egg on the slightest impact. They seem to take a hit as well as the OE. He11, I've destroyed all brands.

Empirical evidence:

We tracked the OE and reman vs SEI we sold for one year when they first came out. OE 1%-2% return for warranty vs. 3%-4% warranty return for SEI. Repeated with following year sales got roughly same result.

$3500 + for OE = 98% probability no warranty issue in first year.

$845 for SEI = 96% probability no warranty issue in first year.

Anecdotal evidence:

"I heard them aftermarket lower units are junk. A bunch of guys that had them blow up said they are made by retarded blind Chinese communists without no thumbs. Plus, the guys at the boat dealer said they aren't any good either and they aren't biased at all. That would be as crazy as the good folks at the tobacco companies saying cigarettes are harmless. Those SEI people designed them with cheap inferior materials like gears made out of balsa wood and Styrofoam bearings and gave a crazy three year warranty just so their investors could lose millions for a tax write off."

Sounds like a solid business plan to me.

Nail a stump with OE and damage the lower and you get to repeat process or deal with your insurance company and pay deductible.

Nail a stump with the SEI within 3 year period you are out $50-$60 for return shipping plus about 2 weeks turn around for repair/replacement.

What size motor are you putting these on? They told me that my Merc 250Pro XB would not handle it. I bought a rebuild from another source.

Your Pro XB will handle it fine. But, the SEI lower unit will not handle the torque of the Pro XB nor will the standard Fleet Master lower unit from the Mercury. Also, the prop will cavitate at higher speeds with the Fleet Master and the SEI (which is a copy of the Mercury Fleet Master).

Pro XS, and XS are High Output engines and are equipped with a Torque Master high performance lower unit. SEI does not make a Torque Master, Sport Master, or Speed Master lower unit replacement and likely never will.

It will fit and go down the lake....for a while. Two butter-knifes will also fit in an electrical outlet but it's not a good idea or a smart way to light a cigarette. It would be like bolting a regular passenger car or truck transmission to a dragster engine.


It'll bolt up but it won't last long or be covered by any warranty.

I used to put them on pretty regular but ca`nt make enough on them to pay to ship back and replace lower oil and do installation for free. I have put 23 on and have had 9 fail. Shafts breaking on 2 Yamaha lowers. I wil get one for a customer but I will not install with out the understanding their is no warranty on my part. They will have to pay for another install +freight +another prop if they lose it.

I'll let him know. Thanks. Pretty much sounds like you are rolling the dice...

I put on one my 200 yamaha last year. No issues as of yet. Went thru the normal break in period as best as I could. I've ran it wide open and Ive just cruised around. Only thing I've noticed is it kinda makes a whining sound while idling after running around the lake for a while. I also noticed some metal shavings when I changed out the lower unit oil for the first time. Not sure if thats normal or not.. Either way I think it was better than having to pay 3 grand for a new one from yamaha.

Ive had my SEI lower unit for about 2 years now and have changed the oil in it twice, oil always looked real good. Have had no problems with mine.

Unfortunately I will be taking option 2 after running into little caney yesterday...and option 3 on a skeg

My brother bought one and about two months old the prop shaft sheared off and dropped the prop to the bottom of the lake. They replaced the lower unit but not the prop. So far the second one has worked fine.

Don't do it unless you want to spend all your fishing time taking off a bad lower unit and replacing it with another under warranty bad lower unit

depending on whats wrong with it i would opt to have it rebuilt. my mechanic in grand prairie quoted me $1200 for new gears and seals. they also straighten prop shafts.