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Author Topic:   Mercury 90-HP EFI Flush Adapter
gbcbu posted 04-22-2007 04:36 PM ET (US)   Profile for gbcbu   Send Email to gbcbu  
Is the water connection used to flush the new 90HP Mercury EFI the same as the tell tale water pump discharge? I had a problem with the connection fitting when I tried to flush the motor after its maiden launch today. I did see the tell tale stream and no alarms were triggered, but, after a second trip, I tried to use the flush connection and had a problem. When I removed the cowl a piece of the connection went overboard and sank.
Maximus posted 04-22-2007 05:35 PM ET (US)     Profile for Maximus  Send Email to Maximus     
I gave up on the provided connection long ago. Get a pair of ear muffs.
Sea Antsy posted 04-22-2007 10:50 PM ET (US)     Profile for Sea Antsy  Send Email to Sea Antsy     
Do you [refer to] the special Mercury flush adapter? The snap-fit auto-shutoff deal that tees into the temperature transducer? I couldn't really see buying a $20 special adapter and keeping it somewhere for when it came time to flush after use. I cut the 1/2-inch line and put on a barb garden hose fitting and use a screw on cap [which costs] $3 at the hardware store.
gbcbu posted 04-26-2007 12:38 PM ET (US)     Profile for gbcbu  Send Email to gbcbu     
Sea Antsy: Yes, I [am referring to] the flush adapter. I use a $2 hose snap connector, too. The dealer installed a new one and the motor is running just fine. I was out yesterday on flat seas, and, boy, does the four-stroke sound sweet and performs fantastically. Still breaking it in. Got to get those break in hours behind me, but it's still a blast going out.
GreatBayNH posted 04-26-2007 10:27 PM ET (US)     Profile for GreatBayNH  Send Email to GreatBayNH     
I just use $4 ear muffs.
swist posted 04-27-2007 10:16 AM ET (US)     Profile for swist  Send Email to swist     
The telltale and hose attachment are in fact one and the same. I never had a problem just for flushing or idling the engine to warm it up. When all else fails, read the owner's manual.
jimh posted 04-29-2007 12:26 PM ET (US)     Profile for jimh  Send Email to jimh     
I am a great believer in the read-the-owner's-manual theory of outboard motor ownership. There is usually a great deal of information in the owner's manual about normal operating procedures.
gbcbu posted 04-29-2007 01:19 PM ET (US)     Profile for gbcbu  Send Email to gbcbu you flush your motor in the up position and run it for 5 minutes as recommended in the owners manual? I just found it somewhat contrary that you'd "block" the tell tale during flushing.

I had to question what was in the manual because of some posts here and also that my dealer said it's not necessary to run the motor. The dealer was surprised at what the manual recommended. Re: flushing (2006 90 HP Merc EFI)

Pg. 58 Owner's Manual

swist posted 04-29-2007 09:01 PM ET (US)     Profile for swist  Send Email to swist     
Well it does seem counterintuitive but attaching a hose to the flush filling obviously is running that part of the cooling system backward, but that's what it says to do and I've never had a problem. Again - this is just for flushing. I would never do a power-up run on that attachment.
gbcbu posted 05-02-2007 02:48 PM ET (US)     Profile for gbcbu  Send Email to gbcbu     
Thank you Swist. We should be able to rely on an owners' manual...but not blindly...and questioing what's in the manual doesn't mean someone didn't read it as another post seemed to imply. Good luck
jimh posted 05-03-2007 08:50 AM ET (US)     Profile for jimh  Send Email to jimh     
What does the 2006 Mercury owner's manual say about running their 90-HP EFI motor when out of the water and using the flush fitting with a water supply?

Mel Wallace posted 05-03-2007 02:03 PM ET (US)     Profile for Mel Wallace  Send Email to Mel Wallace     
It says to lower the motor and keep the rpm's low. I've done it, although I prefer to stick the lower unit in a tub of water and use the proper cooling system. I suppose it's good to "back flush" through the adapter now and then, however. If someone from Mercury reads this website, please request additional clarity on this subject in the manual since it continues to be questioned. Thanks.
gbcbu posted 05-03-2007 03:32 PM ET (US)     Profile for gbcbu  Send Email to gbcbu     
Owners Manual

"1. Place the outboard in either the operating position (vertical) or in a tilted position.

2. Remove propeller. refer to Propeller Replacement.

3. Thread a water hose into the rear fitting. Partially open the water tap (1/2 maxximum). Do not open the water tap all the way, as this allows a high pressure flow of water.

IMPORTANT: Do not run engine above idle when flushing.

4. Shift outboard into nuetral . Start the engine and flush the cooling system for at least 5 minutes. Keep engine speed at idle.

5. Stop the engine. Turn off the water and remove hose. Reinstall the propeller." Pg 56

A call to Mercury confirmed that the "titlted position" is out of the water. As I keep the boat at a slip trying to flush the system while the motor is in the operating position will not work.

I've been out of boating for many years and I'm blown away that the rear fitting allows for the flushing w/o muffs.

Can you understand my caution ?

Mel W, my manual is (c) 2005 and is for the 75/90/115 4-Stroke EFI Models 90-10247060 305

Maximus posted 05-03-2007 10:03 PM ET (US)     Profile for Maximus  Send Email to Maximus     
I completely understand your concern over the procedure in the manual.

After trying to flush my motor per the manual the first time, I decided not to do it ever again like that.

It just doesn't feel right to push water backwards against the spinning water pump. The motor did not sound happy.

After each use, I tilt the motor full up, hook up the hose to the muffs, turn on the water and then start the motor. I idle it for about 5 minutes. The telltale should shoot out about 15 feet!

I've been using muffs for years with no problems. I do use Salt-Away 5-6 six times through the season.

If things go well I'll have my first ride of the season on this weekend.

gbcbu posted 05-04-2007 07:39 PM ET (US)     Profile for gbcbu  Send Email to gbcbu tu...thanks... muffs it shall be. It's great that someone knows exactly what my concern is. Now please tell me about the salt away and how I could use it at the slip if at all possible.

It will be cool in the NE but sunny. Hope you can get out.

Maximus posted 05-04-2007 08:36 PM ET (US)     Profile for Maximus  Send Email to Maximus     
The debate can go on an on about the use of additives and products like Salt-Away. Salt-Away is a product that comes with a hose adapter that claims to wash away salt deposits.

I hook the hose adapter with the chemical to the muffs and flush as usual.

I can not vouch for the effectiveness, but I consider the use preventative maintenance.

I forgot to mention, I try to immediately flush upon returning to the dock as the engine is still warm and the thermostat will re-open quickly.

swist posted 05-05-2007 08:46 AM ET (US)     Profile for swist  Send Email to swist     
I think one would need to see a detailed diagram of the engine cooling system before coming to any conclusions about the factory procedure not "feeling right". If the telltale is at the exit of the cooling system, then by forcing water back throught it, you are reverse-flushing the engine, which I would think would be a good thing for loosening up deposits (running on muffs gives you the normal forward flow). I would then assume the water travels down the water tube and indeed it does seem like it must be hitting the impeller backwards, but I don't think it's that simple because the water exits through the intakes in the lower unit. How does it get by the "backwards" water pump? Does any know for sure the principles behind this flushing susytem?
gbcbu posted 05-05-2007 08:46 AM ET (US)     Profile for gbcbu  Send Email to gbcbu     
Maximus..gratius...great advice and will try it your way.
Will let you know how it goes.
gbcbu posted 05-05-2007 08:49 AM ET (US)     Profile for gbcbu  Send Email to gbcbu     
Swist...great question. I hope you receive an answer to your query as I am just as curious

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