Just bought my first boat, a 2005...

[DestinEd]

Just bought my first boat, a 2005 220 Sundeck with less than 200 hours and in great shape.  Enjoying it quite a bit in the bay near Destin, FL.  Flushing the engine with the muffs is very difficult considering it is on a lift, but really important since we are in salt water.  After asking a few local places about installing a flush kit and getting no response or a crazy number, I'm looking into it since I've got plenty of mechanical experience on cars.

Anyway, I need to look at a plumbing diagram for the coolant system.  I was told that a 1-1/4" T in the water inlet from the outdrive to the main pump would allow me to flush it while idling using a garden hose - makes sense to me.  I just want to be certain that I have the right hose before cutting.  Mine appears to be red and shows 30mm on the hose.  Can someone point me to the section on cooling system diagrams?

Thx, Ed

[Captain_Zero]

The red inlet hose is where you would need to put it. I too have decades of car/truck repair under my belt as a transmission rebuilder/ shop owner. Looking at that pipe, thought easy job..... wrong....lol. That pipe is some of the hardest line I have EVER cut. They make a kit sold at West Marine think it's a sureflow. One way check valve, hose connection, all you need. BUT...if old hose so hard, you need to install new hose....and ONLY use the red hose...I tried every other type hose. All will collapse under acceleration and cause engine overheat. End result for me on a 260 sundeck. Use stock engine mercruiser flush adaptor. Once I installed sureflow even with new water pumps would not allow sufficient water flow under hard use... Good luck..lol

[Tscannie]

I have a 225 Weekender in saltwater. Mercruiser makes a great flush kit but a little pricey. Works great because it flushes on both sides of thermostat even if t stat not open. Had Mercruiser dealer install after they found the kit for me. Chesapeake Cove Marina in Deltaville, Va can help you.

[DestinEd]

Great to finally find people to discuss this with. Hydra, so the red hose must have a big suction to collapse it as you mention. If that hose is so hard, does silicone grease work to help the hose barb slip in? That grease is fine on rubber I believe.

Both of you mention the Mercruiser kit, but I don't find it on the Internet so must be a dealer only thing. I hadn't considered what happens if the thermostat isn't open - how then does the Perko from West Marine work if it is only a T in the red inlet hose when engine is cool? And the muffs, wouldn't they have the same problem if the thermostat is closed - am I missing something here?

[Tscannie]

The kit I had came from the Mercruiser dealer I mentioned before, Chesapeake Cove Marina. After several years of use, the piece you hook the water hose to broke since it is made of plastic. I actually found an entire kit on Ebay for about $50. An individual in California had one he'd never installed. Just checked there again and there are several...I assume for different engines. They range in price from about $150 to $200.

[DestinEd]

OK, after the comments about how hard the red hose is and the overheating issues it seems the Merc kit is the way to go. Seems like a lot of options I see on eBay, so I guess contacting the dealer to identify the P/N makes sense - maybe they'll have competitive pricing.

I've bought a SS piece to mount thru the fiberglass to hook the hose to and won't use plastic unless I have to for the connections. Do you run the engine to flush?

Here is a question that is bothering me: I've been told there is a 3" rubber impeller in the Bravo III (maybe all drives), and running it without water will ruin it because the water is a lubricant. So, if you are flushing with this kit and the engine running how is water getting to that impeller?

Thx again.

[Tscannie]

The plastic connector on the engine bracket is used so that the other plastic connector that fits on the water hose pushes into it. The end result is a quick connect/disconnect connection if that makes sense. They basically lock together on the metal bracket that holds the female connector. Yes, you run the engine exactly like you do with the standard ear muff gadget.
As for the impeller, my Bravo 3 does not have one. The pump that brings in the raw water hangs on the engine, is driven by the engine belt and contains the impeller so there is no issue. The engine is the 5.3L V-8. You need to check your configuration to make sure the impeller is not in the bottom of the outdrive or you will burn it up.

[DestinEd]

Good info, I am certain my 5.0L MPI also has a raw pump because I traced the red hose to it below the engine on the starboard side. Driven by a serpentine belt also.

I wish I could find the coolant plumbing diagram. I was really confused why an impeller was needed with that pump there. I've learned more over the past day than the last 3 weeks - club forum is great.

[Tscannie]

Google brought up this diagram. I'm sure if you go to the Mercury/Mercruiser site you can find the real thing. Hope this one helps.
https://www.marineengine.com/parts/mercruiser-sterndrive-parts/50l-mpi-alphabravo/0m300000-thru-0m599999/thermostat-and-housing-multi-point-drain

[Captain_Zero]

Yea it is a perko.... It has a one way check valve in it. When water pressure applied in front of check valve...ie from hose...that is where it pulls water from. Of course on lift it would be only source. Problem I have seen is that when in water under Power water pressure reduced due to water flow being slowed and pressure being reduced, causing overheat. I would strongly suggest getting new hose. Installing perko in it and install on boat and see what happens. If it overheats you will have original hose to reinstall. And FYI...it is way easier to install by removing exhaust manifold and elbow on starboard side, and raw water pump. All you will need is river gaskets. Make sure you id. Gaskets correctly and install correct ly. And you can use stock manifold gaskets....

[Captain_Zero]

The mercriser fittings can be found at Michigan motorz

[Tscannie]

DestinEd, sorry about that, mine is a 5.7L . The raw water pump is on the starboard side down low, well under the alternator.

[NJAuditor]

Just another thought. I have a 220 Sundeck on a lift in salt water. I use a kayak to attach the muffs to flush. When finished I use the kayak paddle to push the muffs off the outdrive. Its been working for me for the last six years.

[DestinEd]

NJ, thanks but I just don't see me taking a small boat out just to flush the engine every time I use it. Quite an effort for something I need to do 30 or 40 times/year.

[DestinEd]

The guys at Chesapeake Cove Marine are really helpful and knew what they were talking about. My local marina doesn't seem to know anything about it - no details at all, strange. Anyway, he said the Perko and Merc kits are similar and both install in the 1-1/4" inlet hose to the seawater pump. He mentioned that putting the barb fitting into the red hose can be really hard, but gave me a tip to use a heat gun to warm it up so I'll try that.

I really wish there was easier access to this area because this would be a relatively easy job. Removing the exhaust manifold makes it much more difficult.

[Parrot_Head]

I have the exact same boat as you, in Shediac, New Brunswick, Canada, so also in salt water. I would love to hear if your idea works. Please let us know.

[Paulswagelock]

My 270 slx with the 496 had the factory flush kit. I never needed to use it, but it did not affect the cooling system negatively.

[DestinEd]

Sorry it took so long to get back to this. I was dreading working in that tight area and found an experienced mechanic who offered to do it for $140 plus manifold gaskets which I'd have bought anyway. Cheap enough, and everything worked as expected.

I ended up buying a 1-1/4" SS T and barb fittings at an online plumbing place. Also SS reducer and 1/2" barb for the flush line. Bought a SS water inlet port on Amazon and 10' of 1/2" hose.

All is working great with no overheating issues at all yet. Decided to go SS over plastic to avoid possible cracking problems with age, and am wondering why the check valve is needed because at idle my 5.0 takes all my hose can give and nothing comes out of the foot. SS cost totaled about $60 plus another $45 for the port.