Newbie Q: should I flush a stern drive? And how?

[HarrisonCSolo]

Hey folks, I have a lovely Sun Deck 24, it used to be a lake boat but I have it now in sat water. It is 2006 with Mercruiser 5.0 stern drive. The question is - do I need to flush the engine as I see others do with outboards? And if I do how do i do that? I don’t see an obvious place to attach a hose - do I need some kind of attachment? I looked at a bunch of videos on mercruiser website but honestly found them hard to follow.

The reason I’m asking is 1) my slip neighbour
was surprised I wasn’t doing it (but wasn’t sure with a stern drive if I can / should 2) the boat was fine in her first year in the sea (last year) but this year after coming out of winterisation she’s broke down and I had to replace the “risers” as the exhaust was “basically rotted”

I am a total newbie boat owner so ZERO mechanical experience so any advice simply described would be SO welcome. Thank you very much.

 

[ColoSR]

You can use the Mercruiser flush muffs to attach a garden hose to the side of the leg. normally you do it on a trailer, but you should be able to trim the leg to trailer position and attach the hose in The water. If you have a bravo drive, you can install a perko flush kit so that you can attach the hose to a fitting rather than on the drive.

https://www.amazon.com/Quicksilver-...ocphy=9028730&hvtargid=pla-492007035080&psc=1

 

[Chip S]

With the boat in the water, raise the outdrive up and put on the muffs with the garden hose attached. Turn on the garden hose and lower the outdrive. Turn on the engine and run for about 10 minutes. Even though the outdrive is in saltwater it will be sucking in the freshwater from the garden hose. After 10 minutes turn off the engine, raise the outdrive, and remove the muffs. Your outdrive will still corrode from sitting in the saltwater but your engine should be spared.

 

[Espos4]

With the boat in the water, raise the outdrive up and put on the muffs with the garden hose attached. Turn on the garden hose and lower the outdrive. Turn on the engine and run for about 10 minutes. Even though the outdrive is in saltwater it will be sucking in the freshwater from the garden hose. After 10 minutes turn off the engine, raise the outdrive, and remove the muffs. Your outdrive will still corrode from sitting in the saltwater but your engine should be spared.

The swim platform and outdrive position on a 240 Sundeck makes this very difficult. You would basically be submerged from the waist up (unless you slide off the platform) trying to put muffs on the drive.

Mercruiser makes a flush kit that once installed, makes flushing the motor very simple.
https://www.ebay.com/itm/Genuine-Me...2349624.m46890.l49286&mkrid=711-127632-2357-0

 

[Pirate Lady]

Don’t worry about it. Its your first boat, you wont have it in 4 years. You will move upsize, change style, or decide its not for you.
If you haul come winter, flush then, in season flush is a waste of time.

 

[Espos4]

Don’t worry about it. Its your first boat, you wont have it in 4 years. You will move upsize, change style, or decide its not for you.
If you haul come winter, flush then, in season flush is a waste of time.

Maybe, just maybe, flushing could reduce buildup and could prevent overheating.

 

[El Capitan]

Keeping an IO in salt water slip is no bueno. You should consider bottom paint for hull and anti fouling paint for outdrive. Make sure you have zincs in place and keep her covered to prevent rain buildup.

Make sure your batteries are fully charged and your bilge pumps work.

Other than that haul her out once a month and clean the bottom or take her to a sandbar and do it yourself.

 

[Lazy Daze]

Harrison, the reason you see people flushing their OB's so much is simply because it's much easier to do than with a stern drive. Thousands and thousands of stern drives are left in the water with no issues - it just requires more attention to maintenance. So, yes, if you flush it - it's only going to help. It's certainly better to leave fresh water (or mostly fresh) sitting in the engine than salt. Look up Salt Away and Salt Terminator, too.

Like Espos4 mentioned, though, it's extremely awkward with your boat - and other similar boats - to use a muff attachment. The better solution is to install that flush kit he mentioned, or make your own. It's just basic plumbing. If you really wanted to get crazy, you could install a thru-hull water pickup and eliminate the through-transom setup all together... which also eliminates the possibility of "bravoitis" (google or search this forum for info).