Running engine on Trailer.

[jdholt41]

I have a 2005 Yamaha 115 outboard. When the engine is out of the water can I run it using the flushing inlet (just below the cowling) as the cooling water inlet OR must I use a water muff on the inlet in the lower unit?

 

[99yam40]

depends on how much pressue and water flow you have, that is a small hose running to the power head.
Owners manuals say not to.
But some people say to use both muffs and the cowling fitting when running out of the water

 

[crazy charlie]

I have a 2005 Yamaha 115 outboard. When the engine is out of the water can I run it using the flushing inlet (just below the cowling) as the cooling water inlet OR must I use a water muff on the inlet in the lower unit

The flushing port is for FLUSHING. You must use muffs on the lower unit to draw the water through the impeller and up to the block. You run the very good chance of ruining the impeller if you run the motor using flushing port only. When I am running on muffs,I first fill the block by using the flushing port.Then switch over to the muffs .I recommend allowing the water from the muffs to run for at lease a minute or 2 before firing up the motor.Yamahas dont seem to like running on muffs.Some are difficult to "prime" when running on muffs.I also duct tape my muffs on to keep escaping water flow to an absolute minimum.Charlie

 

[QBhoy]

No. You can’t. You’ll burn up the impeller if it’s the function I’m assuming it is. On my outboard the flushing port is for attaching a hose to when not running (or can’t) to flush it, just with the positive pressure of the water hose. If you want to run the engine to flush…you need to use the muffs usually.

 

[mike_i]

crazy charlie and QBhoy are both 100% right.​

 

[boscoe99]

Many run their Yamaha outboard motors at an idle RPM using just the garden hose flush fitting with nary a problem.

Water flows down the water pump tube and lubricates and cools the impeller.

 

[boscoe99]

My experience anyway on many different Yamaha models.

 

[Chris1956]

Gee, that info is usually in the owners manual. Anyone look there?

 

[boscoe99]

Owner's manual says to not run the motor if and when using the garden hose flush fitting.

Many are wanting to know if they can do it anyway without causing any harm to the motor.

Owner's manual says not to do a lot of stuff that is successfully being done daily.

 

[boscoe99]

Owner's manual says to not run the motor if and when using the garden hose flush fitting.

Many are wanting to know if they can do it anyway without causing any harm to the motor.

Owner's manual says not to do a lot of stuff that is successfully being done daily.

Owner's manual is intended to address the dumbest of the dumb. For the really dumb, it is recommended they don't run the motor using just the garden hose flush fitting.

Same thing applies to the meek and timid.

 

[saltchuckmatt]

I believe it's best not to run the motor unless on muffs or in a barrel. The impeller will not allow water to go through it backwards.

 

[dingbat]

The impeller will not allow water to go through it backwards

If the impeller is a physical barrier, how is it that I can run my 200hp Evinrude using the flush port per the manual?

In reality, vane pumps are reversible, high flow, low pressure pumps. At idle, you’re typical outboard is pushing 3 to 4 psi water pressure.

You would have no problem reversing the flow through the pump with typical garden hose pressure of 30-60 psi

 

[KJM]

I believe it's best not to run the motor unless on muffs or in a barrel. The impeller will not allow water to go through it backwards.

I would think that as long as water gets in there it won't burn up. Water would have to get in there between the vanes from the weight of the water above the pump.

 

[KJM]

I know the manual says not to, but the Yamaha dealership here sent me a video of the motor I eventually bought with the motor being run on the flush outlet. These are certified Yamaha technicians, so I assume they knew what they were doing. That being said, I still use muffs If I start the boat out of water, why chance it?

 

[airshot]

Many run their Yamaha outboard motors at an idle RPM using just the garden hose flush fitting with nary a problem.

Water flows down the water pump tube and lubricates and cools the impeller.

While it might work, not sure I would take that chance, get good muffs and be sure!

 

[airshot]

I know the manual says not to, but the Yamaha dealership here sent me a video of the motor I eventually bought with the motor being run on the flush outlet. These are certified Yamaha technicians, so I assume they knew what they were doing. That being said, I still use muffs If I start the boat out of water, why chance it?

Being certified today means that you passed a few hours of online training and recieved a piece of paper that says so !!! Doesnt mean much !!! Just look at the number of dealer repairs that have gone wrong, starting with consumer reports...in the old days there was a saying that was often used...." I went to school to become a teacher, and now I are one"...

 

[KJM]

Being certified today means that you passed a few hours of online training and recieved a piece of paper that says so !!! Doesnt mean much !!! Just look at the number of dealer repairs that have gone wrong, starting with consumer reports...in the old days there was a saying that was often used...." I went to school to become a teacher, and now I are one"...

I was thinking along the same lines, thats why I still use muffs!