Flushing 8.1S Horizons

[cthronson]

I have a 2003 380 DA with 8.1S Horizons. I mentioned this in a previous post, but would be interested in knowing how many out there routinely fresh-water flush their risers and manifolds.

My service guy has suggested a flush attachment, and apparently Perko has a valve that looks like it would do the trick. Anyone use this setup?

Thanks

 

[jackson]

flush

I'm not sure if the perko unit you are talking about is for this application. Others on the board suggested this, I bought a spare perko strainer cover and I'm having a local machine shop tap a garden hose attachment into it. Mine is for the a/c strainer for the purpose of winterization, but would be the same for the other strainers. I can post a pic when I get it back from the shop.

You brought up a good idea about flushing the exhaust using this method. I may do the same thing with the other strainers.

 

[rondds]

ive done what was mentioned above - purchased a spare perko cover, drilled, tapped it for a garden hose attachment. i use that for my genny and my a/c, purely for winterization. ie: i only attach it to the strainer in the fall to run the pink stuff. during the season the regular strainer caps are in place. for the engines, see the pic below, this is what i use to flush out before i go home every weekend. i run each engine for a few minutes using a garden hose. so yes i do flush the engines routinely. i am FWC but this flushes out the risers.

 

[osd9]

You can buy these from Groco.....but Ron's solution will do the same thing for less $$$$

 

[cthronson]

It's interesting. Mercruiser on its website recommends flushing the engines after saltwater use, and then goes on to say that they don't have a kit for that purpose on inboard engines.

Perko has a system called "Perko Flush Pro." (Sounds like something from the Vacuflush people...) that is an in-line device that uses a spring to divert the cooling water flow to a garden hose through a threaded fitting when the hose is pressurized. Looks pretty sano and relatively easy to install. I think the Perko number is 0456DP7

 

[dc380]

I also bought a spare set of perko covers and have a hose fitting drilled and soldered in.
I’ve used them for winterizing only, since up until now the boat was slipped in fresh water. Now however my permanent slip is in salt water, and I’d like to use the hose fittings to flush the salt water out of the exhaust system with fresh water and salt-away.

The manual states to only turn the hose on at 1/3 to ½ pressure. Does anyone know why?
When I winterize, the engine pulls 6 gallons of antifreeze from the bucket pretty quickly, say 30 seconds or so.

The manual doesn’t mention whether you can turn the hose on before starting the engine, or should I start the engine, let it pull sea water in, then open the hose valve, then shut the sea water valve?

 

[osd9]

...... or should I start the engine, let it pull sea water in, then open the hose valve, then shut the sea water valve?

Just as another option, here's what I've done:

Attach a shut off to end of the water hose.
Attach "The Bucket" to the strainer/flusher.
Put the hose in the bucket and Turn on the water to fill "The Bucket".
Start the engine
Open the strainer/flusher valve.
Close the Seacock.
Adjust the valve on the hose end so that the engine always has enough water in "The Bucket" and not so much that "The Bucket" overflows.

In this way, the engine decides how much flow of water it needs without overpressurizing anything.

When I winterize, I go through the same procedure as above to flush the engines first. Then, after all is well flushed, I shut off the hose, and let the engine pull "The Bucket" just about empty and then shut the engine. I then fill "The Bucket" with the pink stuff and restart the engine until all the Pink is pulled through the engine and shut the engine.

 

[dc380]

I like that, and you can throw in the Salt-Away right in the bucket at the very end. I was reluctant to flush the engines last weekend, with just a hose because I didn't understand why the water pressure may a difference.

 

[rondds]

i start the engine with the hose attached but the gate valve in the strainer OFF. then i climb down the bilge and open the gate valve as is simultaneously shut the seacock. i do not allow water to flow into the fitting prior to starting the engine. not sure if pressurized water could make it past the impeller, but if it could, you could ingest water into the engine and cause hydrolock (catastrophic engine failure!)

when shutting, i turn off the water (with a ball shut off at the end of the hose) and RUN to the breaker panel (5' away) and shut the engine. the VERY NEXT THING I DO, almost obsessively, is shut the gate valve and open the seacock again. this is a step you CANNOT forget b/c the next time you start the engine, you can fry things pretty good with that seacock still in the closed position.

as far as the hose pressure, not sure how merc would be able to suggest how much to open the hose valve. pressure differs from water supply to water supply, even from day to day. you dont have the same pressure on a 95 degree day as you have on a 70 degree day. you can tell if the engine is starving for water b/c the suction will collapse the garden hose. you have to play with it - it's a feel thing. i have inboards with above-the-waterline exhausts only, so i know what adequate flow should look like. not possible for I/Os andnot sure if it'll work on the combo above/under-water exhaust systems.