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Thread: SEI 116 Lower Unit Failure

  1. #1
    Join Date
    Jun 2017

    Unhappy SEI 116 Lower Unit Failure

    I have a restored 1992 Sea Ray 220BR, third time out on the lake this year and my lower unit failed. It's currently in for warranty work. What I'd like to know, did this happen to anyone else? The unit was purchased and installed in April 16, ran great the entire season. Then this year while running across the lake at about 2800 RPM, the boat quit, acted like it popped out of gear. I immediately chopped the throttle and checked the waters. I was in clear/35 ft water. Couldn't see anything that I could have hit. Throttle would move to FWD, but would bind when attempting REV. Towed back, checked/adjusted cables (minor tweak), same result. Cable freed up but would not shift in to gear. Pulled top cap on upper unit to inspect, all clean/no metal damage. Drained outdrive, only minor dust particles on plug magnet. Pulled lower unit and found it bound up. Would not rotate. Turned unit and it sounded like something was rattling around inside the "bullet". All shafts and splines, pump and seals were good. Just curious, without any visible damage...what could have gone wrong? Hopefully I'll get it back soon!
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  2. #2
    Join Date
    Jul 2017


    Yes, unfortunately I've now blown two lowers. We have a 1998 290 Sundancer with T5.7EFI's on alphas. Last year at cruise (3400 engine RPM) we blew a gear straight out the side of the lower unit. SEI replaced it, but it cost us 2.5 weeks of our 4 month season. They reported lower unit failure as a result of improper break-in. I can't confirm the break-in procedure was followed to the letter because I bought the boat with the drives on it, but the lower only had 60 hours.

    Last week I blew the other lower unit with similar results. This time, no gear was thrown through the housing but rather the lower unit locked up while at idle and as a result we sheared the vertical drive shaft off at the splines where it enters the upper. That unit is now back out to SEI and I paid $180 to 3 day express it down there in hopes of not wasting nearly 3 weeks again this year. Hopefully I get it back soon, but even with warranty coverage it is costing us a good amount of money since I have to pay haul out, blocking fee, and re-launch. Unfortunately SEI would not send me a replacement lower while I shipped the bad one back, even though I offered to pay for the replacement in full in the meantime while they evaluate the broken one.
    Last edited by Strecker25; 07-17-2017 at 10:40 AM.

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115 S. Forest Lakes Blvd.
Oldsmar, FL 34677

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Sterndrive Engineering, Inc. (SEI) manufactures a stern drive designed to replace Mercury Marine's MerCruiserŽ Alpha OneŽ, R, MR, Gen II and Bravo OneŽ stern drives. MerCruiserŽ Alpha One, R, MR, Gen II and Bravo OneŽ are trademarks of the Brunswick Corporation. SEI has no affiliation with the Brunswick Corporation. Consequently, any warranties governing products and or sold by Brunswick Corporation will not apply to products manufactured and or sold by SEI, or to products damaged due to the operation of an SEI product.