# Confusion on flushing a Yamaha 250SHO with engine running



## Cavjock22 (Jan 5, 2008)

The book reads to not start the engine when your using the hose flush adaptor. Also read a similar note in "hull truth". Your only suppose to flush the engine running using muffs. Can any body set it straight? Can you run the engine when you use the hose flush adaptor up top?


----------



## Profish00 (May 21, 2004)

Run engine on muffs, do not run on flush adapter.


----------



## Cavjock22 (Jan 5, 2008)

Boat sits on a sling. I probably should have given that bit of info. Muffs are a pain to use.


----------



## Profish00 (May 21, 2004)

doesn't matter if in sling.

Run engine on muffs, do not run engine on flush adapter.


----------



## g2outfitter (Jul 21, 2009)

Just use flush adapter and dont run engine. Use salt away and run through engine, I never had issue and engine stayed clean and I never ran motor on muffs. 

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2


----------



## Cavjock22 (Jan 5, 2008)

What happens if you run the engine thru the hose adaptor?


----------



## Profish00 (May 21, 2004)

Cavjock22 said:


> What happens if you run the engine thru the hose adaptor?


Big puff of smoke, kidding.

Don't know manual says not to so I don't. Why would you want to?


----------



## Stuart (May 21, 2004)

Cavjock22 said:


> What happens if you run the engine thru the hose adaptor?


Not sure if water reaches the water pump through the hose adaptor. If not, at the very least ,you'll burn your water pump up.


----------



## SeaY'all (Jul 14, 2011)

Water does reach the pump when using the flush adapter. The manual says do not run unless you use muffs. Just flush it with salt away.


----------



## 2slick (Dec 5, 2008)

No water to pump inlet on flush. Suzuki is the same way. 


Sent from my iPhone using Tapatalk


----------



## Kenner21 (Aug 25, 2005)

SlickWillie said:


> No water to pump inlet on flush. Suzuki is the same way.
> 
> Sent from my iPhone using Tapatalk


 Are you sure about that I've had two separate shops tell me it's fine to run a DF250 Suzuki from the flushing port.


----------



## Big Grouper (Oct 1, 2008)

When using the flush adapter, water is going in through the outlet of the water pump. It flushes through the water pump but backwards. If you run the motor, the water pump starves for water as it is trying to push it out and nothing is coming in the water pump inlet. The engine has plenty of cooling from the flush circuit but the water pump is starving.


----------



## Tejas Trucha (Feb 28, 2011)

My yamaha mechanic, who is otherwise a very "by the book" guy, says fine to run the SHO on the flush port. He does it all the time to get salt-away through the entire engine. Make sure the water is coming out of the pee-hole and the lower unit water intakes before starting. I've been doing it this way for the last few trips with no issues so far.


----------



## Cavjock22 (Jan 5, 2008)

My 250 SHO has 70 hrs on it and it's been getting flushed while running using the hose adapter. No problems to date.


----------



## bayrat68 (Nov 21, 2011)

I have the 250 Vmax HPDI and my mechanic says it is fine to run the motor on the flush adapter as long as it is done only at idle. The water will fall on top of the water pump impellar enough to keep it cool at idle only. Running the engine will allow it to reach operating temps high enough to open the thermostats and allow fresh water to flush all water jackets. I have been doing this procedure for several years and no problems at all. I also change my water pump annually and t-stats every other year.


----------



## SeaIsleDweller (Jun 27, 2013)

I use to flush my 90 Yamaha on the quick flush connection and run the engine, and was burning up my water pump every season. The water pump does not get proper water pressure when using the quick flush, If your going to run it use the muffs you probably wont see immediate problems if you do run it on the quick flush but you will notice them long term. And as far as putting muffs on while its in the lift the easiest thing to do is trim the motor up a bit and reach over the transom.. I have been doing it for years on all different type of boats and never had a problem.


----------



## lrobalo23hps (Aug 19, 2014)

*Flush*

My Yamaha mechanic said to use two hoses. Hook one to the sling type muff and one to the hose adapter and run them at the same time with the engine running. Of course you need the kind of water pressure for that. I use city water on the sling and my well water pump for the hose adapter. Water coming out the pee hole stays warm and the water pours out the bottom....worked like that for 2 years.


----------



## [email protected] (Oct 12, 2014)

Its call a quiet flush because you don't need to run it while flushing.


----------



## cruss (Aug 31, 2005)

*running*

if the motor is not warmed up I dont think the fresh water will flush the powerhead because the themostats will be closed at least that is what i was told by an expert. I run mine at idle for 5 minutes to open the stats then kill the motor and let it flush. No problems for two years.


----------



## Ronnie Redwing (Mar 11, 2013)

Remember ,that the v6 SHO use a "nose one type gear case " the motor flusher is different between the old HPDI vmax Nose cone type and theproper flusher for a SHO gearcase


----------



## Big Fish (Feb 4, 2005)

I have a Yamaha 225 SHO an when I use the hose flush the without the motor running it will "pee" ( I have not flushed the motor this way with the motor running.) When I use the nose cone flush with the motor running it does not "pee". So I am confused as to the best and safest/proper way to flush the motor.


----------



## Empty Pockets CC (Feb 18, 2009)

Hose adapter without the motor on for 10 mins. 
Rabbit ears if you want to run the motor. It won't matter though as the thermostats won't allow water passage. 
Think about it, the flush adapter pushes fresh water backwards through the motor. Why would you run a motor with its cooling system in reverse? Just doesn't make sense to me at least.


----------



## [email protected] (May 27, 2013)

It doesn't seem to make much sense to try to force water into the discharge side of a water pump when it's running. Doesn't the pump need water for lubrication and cooling. Do they make a top-down flusher for a Zuki? I like that idea.


----------



## bpoutsider (Jan 29, 2014)

It's like putting on a raincoat to go set the lawn sprinkler....what's the point?


----------



## BATWING (May 9, 2008)

I am glad there are people out there who are willing to try things outside of what is directed from the mfg but I will not be one. Keep us posted on how back-flushing under power works out.


----------



## bigfishtx (Jul 17, 2007)

Water pump impeller needs water to lubricate it, and it will not have enough water using the engine flush connection. 

Why do you want to run the engine while flushing? It does not accomplish anything other than potentially causing damage to the water pump impeller.


----------



## Profish00 (May 21, 2004)

BATWING said:


> I am glad there are people out there who are willing to try things outside of what is directed from the mfg but I will not be one. Keep us posted on how back-flushing under power works out.


Yea I blew up the motor flushing on the adapter because it was running even tho I read not to do it.:headknock

That will be 18,000 to fix sir, Thanks


----------



## Quackerbox (Feb 6, 2006)

Mechanic told me the best way is to stop by a freshwater lake on the way home, back in and run it.

Ive used the ear muffs for years without an issue.......till last year. New water pump installed at 12 hours on a F150 yammy. Im using a cut down barrel of water this year


----------



## Cavjock22 (Jan 5, 2008)

I'm am confused. When I use the hose adapter and run the engine the motor pees out plenty of water. I don't belive a water pump impeller would last 70 hrs if it runs dry when I am flushing.


----------



## bigfishtx (Jul 17, 2007)

Cavjock22 said:


> I'm am confused. When I use the hose adapter and run the engine the motor pees out plenty of water. I don't belive a water pump impeller would last 70 hrs if it runs dry when I am flushing.


Well keep doing it even though mechanics tell you not too. I know running rubber parts against metal, dry, is not good but seems to be working good so keep doing it.

I just don't know why you want to run your engine while flushing? What is that supposed to accomplish?


----------



## Sgrem (Oct 5, 2005)

Seems you have every answer and suggestions and owners manual to tell you exactly how to do it correctly.

Ultimately do whatever you wish. Just please stop asking for advice which you won't recieve......


----------



## hockeyref999 (Aug 12, 2005)

I have never understood why people think the other guy at the boat ramp knows more about Yamaha engines than Yamaha. I have had four Yamahas, 60, 75, 150 and my current 200 SHO, and I have followed the owner's manual like the Bible. I have had excellent service from each engine. It seemed weird not to use flush cups and run the 200, but I flush for 15 minutes on the hose just like they say. Yamaha knows what's up.


----------



## Empty Pockets CC (Feb 18, 2009)

Cavjock22 said:


> I'm am confused. When I use the hose adapter and run the engine the motor pees out plenty of water. I don't belive a water pump impeller would last 70 hrs if it runs dry when I am flushing.


Stop being confused. Simply stop running the motor if using the flush adapter and garden hose. Easy, and now you're not confused anymore.


----------



## zack3476 (Jun 22, 2012)

Bernies in Victoria say they have been flushing yamis with the motor on using the the hose adapter for a very long time. I have also had the discussion with rockport marine and they said the same. I flush my 90 with the motor on using the adapter for 10 plus minutes while I dry the boat off.


----------



## Profish00 (May 21, 2004)

yall should take this up with Yamaha and make a difference.


----------



## txteltech (Jul 6, 2012)

Empty Pockets CC said:


> Hose adapter without the motor on for 10 mins.
> Rabbit ears if you want to run the motor. It won't matter though as the thermostats won't allow water passage.
> Think about it, the flush adapter pushes fresh water backwards through the motor. Why would you run a motor with its cooling system in reverse? Just doesn't make sense to me at least.


Amen, the hose adapter is for engine off, muffs over water intakes on lower unit for engine on. This is the way it's always been!!!!


----------



## bigfishtx (Jul 17, 2007)

Why so you guys want the engine running while flushing? What does that accomplish?


----------



## 2slick (Dec 5, 2008)

bigfishtx said:


> Why so you guys want the engine running while flushing? What does that accomplish?


I think it's just the fact it was done that way before engines had flush ports. Like they say, old habits are hard to break.

Sent from my iPhone using Tapatalk


----------



## Boats Etc. (Jan 22, 2015)

*Yamaha Flush*

We are a certified 5 Star Yamaha Dealership. My 5 star mechanic told me to tell all of my customers this.

-IF you flush the motor through the flush port Yamaha supplies you with: Yamaha does not want you to crank the motor because we have had bad habits (as everyone implied) It's okay to crank the engine AS LONG AS YOU DON'T REV THE ENGINE! Think about it. Your water pump is in the lower unit. When you rev the engine the lower unit will "suck" air and force the air up through the motor causing you to burn up your water pump. If your idling it will not hurt the motor because your forcing water down through the motor and its enough to keep everything cool. Personally, I don't crank my engine while using this port.

If you use the high speed pick up flush to flush the engine (only one you can use on the SHO motors you can pick this up at your local Yamaha outboard dealer, old muffs just wont fit properly) you may crank the engine and run it how you please because your forcing the water inside the motor the proper way it was designed. Hope this helped.
-Dylan :cheers:


----------



## Captain Dave (Jul 19, 2006)

x2.. from multiple yami shops on a 2 stroke.. no worries.. just don't rev it . or let it idle a long time.. over 500 hrs on this yami I own and replaced the wp a few times.. looks next to new ..



Boats Etc. said:


> We are a certified 5 Star Yamaha Dealership. My 5 star mechanic told me to tell all of my customers this.
> 
> -IF you flush the motor through the flush port Yamaha supplies you with: Yamaha does not want you to crank the motor because we have had bad habits (as everyone implied) It's okay to crank the engine AS LONG AS YOU DON'T REV THE ENGINE! Think about it. Your water pump is in the lower unit. When you rev the engine the lower unit will "suck" air and force the air up through the motor causing you to burn up your water pump. If your idling it will not hurt the motor because your forcing water down through the motor and its enough to keep everything cool. Personally, I don't crank my engine while using this port.
> 
> ...


----------



## rattletrap (Sep 9, 2005)

Boat in a sling . I flush with the side hose adapter after most uses (idle only) , 617hr , no issues.


----------



## Boats Etc. (Jan 22, 2015)

Sold!


----------



## TXFishin (Apr 26, 2010)

My manual says the preferred method is using Flush Cups, as this completely flushes all the water passages in the same manner as they are meant to run.

"If flushing using muffs is not an option, you may use the flush port on the side of the engine.

Note: When using the flush port, DO NOT run the engine, as this can cause internal damage, including water pump and over heat"


On another area I see the flush ports are most commonly used for winterizing engines in colder climates

As for the "pee stream" when using the flush port, this has nothing to do with the waterpump working, this just means water is making it to the power head

All I know, I've always flushed my engines in the way that they were designed to run, using the muffs. I don't have to question if it's getting proper cooling or the water pump may be damaged due to lack of lubrication from not having proper water flow.

It's worth the piece of mind and not questioning a method that could cost you a new engine at the price of a compact car for no real reason. I'm not willing to take chances like that, regardless of the inconvenience, it's all just part of owning a boat and routine preventative maintenance, the cost of not doing this can break the bank, at least for me, I don't have the resources to play with like that.

Relentless


----------



## kinja (May 21, 2004)

And then there are those old salts with thousands of hours whom rarely if ever flush the motor. Without issue.


----------



## Snaggletoothfrecklefish (Jul 11, 2016)

I flush the motor using the flush port after every use. I've never even thought of cranking the motor with the garden hose hooked up. But to each their own.......


----------



## acassidy (Jun 25, 2004)

Great information here, thanks everyone


----------



## EvansMarine (Jun 7, 2010)

It's fine to run on water hose. The main reason for the manual saying not to run on hose attachment is due to customers reving motor while on attachment. There is plenty of water to water pump at idle, but not to rev motor. I only flush when motor is warm and running.


----------



## BayouBonsaiMan (Apr 14, 2009)

EvansMarine said:


> It's fine to run on water hose. The main reason for the manual saying not to run on hose attachment is due to customers reving motor while on attachment. There is plenty of water to water pump at idle, but not to rev motor. I only flush when motor is warm and running.


I read everything Evans writes! I flush my 06 thru the port without motor running but do so with motor warm. Might start running at idle now.


----------



## TXFishin (Apr 26, 2010)

Pattillo said:


> And then there are those old salts with thousands of hours whom rarely if ever flush the motor. Without issue.


That is so true though

I've seen a tiny coral reef strapped on the back of boats, looked like someone's prop has gotten stuck in a reef, only to find out there's an outboard motor in there somewhere and the guy is going to check his crab traps, hits the key and it's running instantly

There used to be a guy with a smaller crab boat at the ramp I used to go to allot, barnacles growing all over the lower unit, probably holding decent fish lol, he would jump in, hit the key, that thing would fire up on the first stroke and off he went.

Other times, take pristine care of it, and something as simple as a stray ground and the lower unit rots off sitting in the drive way.

Relentless


----------



## TXFishin (Apr 26, 2010)

EvansMarine said:


> It's fine to run on water hose. The main reason for the manual saying not to run on hose attachment is due to customers reving motor while on attachment. There is plenty of water to water pump at idle, but not to rev motor. I only flush when motor is warm and running.


Out of curiosity, how does the water pump get proper lubrication this way?

Wouldn't the water just be splashing on top of the impeller, with the impeller trying to throw the water back up the supply tube, or is there enough water pressure to force water down into the water pump housing and surrounding area?

Also, is there any advantages to using the flush port? It seems the main advantage is being able to 90% flush your engine without having to run it, so running the engine on the flush port seems to somewhat defeat it's purpose, unless it's to open the thermostat, even still, in which case if I was going to run the engine using the flush port, might as well put the cups on it and do a 100% flush

I've been curious about the flush port every since my 99 Optimax had one on it years ago, I just never found any advantage to use it, or thought that it flushed the engine as well as it does running it on the cups.

I just assumed with the manuals recommending the flush cups, that the flush port was a second best alternative if for some reason you couldn't use cups, otherwise they would recommended the port as a first and the muffs as an alternate

Relentless


----------



## trout hound (Aug 12, 2012)

Tejas Trucha said:


> My yamaha mechanic, who is otherwise a very "by the book" guy, says fine to run the SHO on the flush port. He does it all the time to get salt-away through the entire engine. Make sure the water is coming out of the pee-hole and the lower unit water intakes before starting. I've been doing it this way for the last few trips with no issues so far.


this is correct if you watch the water pump inlet you'll see water coming out of it even while running and all it takes is a little water to lube and keep it cool I'm sure that when the Yamaha people wrote it in the manual not to do this what they had in mind was that some people wouldn't be patient enough to let the engine fill with water before starting and that would be hard on your pump. I've been doing this since they first started putting these on the motors. as a matter of fact I've purchased two motors in the last two years both motors had the P.D.I done on them for the warranty one at Meeks and one at boats ect. both of these shops ran the motors on the flush port below the cowling.


----------



## tomres2003 (Oct 29, 2005)

Been told SHOs weren’t designed to just idle.. They were made to run.. At idle they have a tendency of making oil.. Probably why no one ever puts SHOs on offshore boats?? 🤷‍♂️🏻


----------

