Running Outboard with Hose Hooked Up

[UMC]

My yamaha outboard has the freshwater flush hook up where you can just thread a garden hose to it. Can I run the motor with that hooked up (which would eliminate the need for earmuffs or filling a tub) in the driveway? Seems like you should but I guess I'd like some assurance before I do. Thanks

[Ufatz]

Boy I sure hope you can-I've been doing it with my 2004 115 Yammie and so far it has done no harm; the engine starts instantly every time and I have replaced impeller and one small electronic doo-dad in the past ten years.

Between Yamaha and Honda outboards I can't imagine anybody making them any better.

And I'll take a 3208 Cat, 555 Cummins or Perkins marine engine any day too! Ha Ha Ha. And of course the 671 Jimmy if you just gotta have SOMETHING in the engine compartment.

[UMC]

That's kinda what I figured but when I assume things with motors I'm usually wrong. Especially just to idle, seems like it'd be fine.

[Black_Bay]

That's for flushing the outboard with freshwater and not meant to be used for running the motor. You're actually pushing water backwards through the system.

[MuskieJunkie]

I have heard you should not but plenty of people do. I have done it and changed that impeller shortly after - it did not have any visible damage.

It simple enough that I would just use the ear muffs if it was me.

[Ufatz]

Yes, it IS a flushing system/attachment, BUT the book that comes with your engine TELLS you to run it and how to use it BUT (and common sense should tell you) NOT to run it at high RPMS and not for extended time.

Too long and high RPMS and you risk overheating the engine. I almost always trust what the maker of an engine tells me to do, assuming that it THEY made the engine THEY will know what is best for it.

Of course you have to READ the manual! LOL

[harvey lee]

I have use that attachment to flush my Merc 4 stroke. No issues to date and I have done this for 6 years now.

[BobT]

Different motor but on my E-tec the hose fitting is actually over the pee port. So I asked my dealership if it is safe to run the outboard with the hose connected and I was told that is what it is for.

[SkunkedAgain]

My Suzuki 90hp 4-stroke has two different ports for flushing. One with the engine off and when while running. As for all of the "I've been doing it for X number of years" comments, I did many many neutral drops in my old Mustang for probably six years from age 15-21. It never had a tranny issue. That doesn't mean that it wasn't doing harm. I cooked the motor before the tranny ever dropped out!

Ufatz is on target. Read the manual or find it online if you don't have one. If not, talk to your mechanic or dealer. I'm sure that Yamaha made many outboards with different methods of flushing over the years.

[solbes]

No would be my answer. At least not in looking at my manual (you can find yours easily in the Yammy HSOforum). They list the hose connection to be used with the engine off as part of the antircorrosion measures section. Probably does not damage the engine though if you do it for short bursts and for very low RPM's. They have a seperate section for fogging the motor that requires the muffs.

I typically hook up the hose to the garden hose connection first and run for 8-10 minutes with the engine off. Then hook up the muffs and start up the engine while I'm warming the engine up for an oil change and preparing for fogging.

Whatever you do, remember to hook that hose connection back up to the threaded connector on the engine, or you will not have proper lake/river water flow through the engine when you get back on the water.