Update on engines....back to the drawing board lol

[seasick]

I just run mine on the flush fitting - the little female hose connector right under the cowling. Any reason that isn't mentioned as an option?

The Yamaha owners manual says not to run the motor on the flush port. That said, I know mechanics that do so and says it works fine. I have tried it but it makes me nervous.
For the record, some motor makers like Mercuries state in their manual that it is OK to run on the flush port.

On the Yami, the hose that the garden hose connector uses is small diameter and doesn't pass a lot of water. In addition, the motors seem in most cases to run without over heating with that hose left dangling which happens often enough

 

[DennisG01]

The Yamaha owners manual says not to run the motor on the flush port. That said, I know mechanics that do so and says it works fine. I have tried it but it makes me nervous.
For the record, some motor makers like Mercuries state in their manual that it is OK to run on the flush port.

On the Yami, the hose that the garden hose connector uses is small diameter and doesn't pass a lot of water. In addition, the motors seem in most cases to run without over heating with that hose left dangling which happens often enough

Agree. Take a look at the hole in the female garden hose fitting - it is even smaller than the feed hose. The other concern is that there "might" not be enough water dropping down to the impeller to keep it from frying - although I've heard that enough water does drop down there. But, it may (in both cases) largely depend on the the amount of pressure and flow rate that a particular garden hose supplies. There's variables at play here (including a particular engine model) that prevents a blanket statement of "it'll be fine, I've seen others do it". For me, I only run the engine while on the muffs - after all, it's not like it's hard to do. If I use the garden hose connector, it's only while the engine isn't running - which is perfectly fine and does a good job at flushing things out.

Also... what if there was a small blockage in that flush adapter hose? It wouldn't take much to block the flow enough to overheat things and/or fry the impeller.

 

[wspitler]

Some Yamaha manuals warn against it. However, I do it also and was advised by a veteran Yamaha HQ tech that it is fine at idle RPMs. It seems to my engineering mind that if the impeller stays wet (and it does) and the engine doesn't overheat, all is good. I think Yamaha is being conservative so that someone won't run an engine at high RPM with a weak hose and then blame the damage on Yamaha's approval.

 

[ScottyCee]

Yes, clearly idling in neutral is the application here so probably OK. Mine have always peed every bit as hard on the flush port as with earmuffs, and I have no plans to stop flushing this way...

 

[seasick]

Dennis makes a good point. If the water flow is insufficient at either speed or at idle, the motor could over heat but more importantly, the impeller could run dry before the upper end over heats. Think about the water flow. Normally the water pump is submerged when in the water or flooded when on muffs. It pumps water up the tube to the power head. When on the flush port with the motor not running, water will flow backwards down the tube as well as out the exhaust. If the motor is out of the water, on the flush port and running, any water that flows backwards down the water tube will get pumped back up by the spinning impeller. Whether or not that scenario supplies sufficient lubrication and cooling to the impeller and housing is the big question. I just don't feel comfortable with that.

 

[Halfhitch]

My old 3.3L F225 would start peeing right away on the muffs but when I repowered with a 4.2L, I found that it took a long time before it would fill the heads and start peeing. I couldn't make myself keep it running that long without seeing proof that the impeller was in water. I started taping the bullet intake ports like always, then I put a garden hose tee on my hose and put two short hoses on the output of the tee. One to the muffs and one to the static flush fitting. Now I have water peeing before I hit the starter.

 

[seasick]

I knew a friend with a Yami 150 4 stroke (maybe it was a 200). Anyway, one day after rebuilding the water pump, he asked my opinion on a problem he was having. On land and on muffs, he couldn't get the motor to pee when started.. So assuming he did something wrong, we dropped the LU and pulled everything apart, reassembled and tried again. Still no telltale.
Couldn't figure it out so we pulled a t-stat, turned on the muffs and ... no water out of the t-stat housing..
After we tried everything we could think of, we decided to open the t-stat housing, turn on the muffs and start the motor. Water came shooting out of the t-stat hole so we knew that the pump was working.
Still at a loss and out of ideas about the telltale, we called it a day. Next day he tells me that all is fine. I asked what he did and he said;" I launched the boat, started the motor and it runs fine"!

That was 10 years ago when I learned that the water pressure, hose diameter and hose length (it was a long hose in the boat yard) are all factors on how much water gets to the power unit and sometimes it isn't enough for the telltale on those Yamis to work.

 

[glacierbaze]

My 2007 LF250 has the switch on the port side and my F250 on the starboard side. Not sure why they configured it that way.

Both being outboard makes them easier to access.

 

[ROBERTH]

I run mine in a tank also, but make sure you get one tall enough to go over the plate as if it was submerged. My HPDI's don't want to pee unless they are very well submerged. I have to block my tank up so that the lower unit is touching the bottom of the tank to get mine submerged deep enough, then no issue. I have a 50 gallon tanks back when Lowes was selling the heavy duty clear tubs. Can't find them anywhere nowdays!

 

[Shannon C.]

I didn’t see it mentioned yet but these flush bags are what I use, built well and very compact when not in use.

 

[glacierbaze]

Sewed one up out of some shower liner that I had left from a project. I use two or three short bungees to attach the grommets at the top of the bag over the lower cowling, and that holds the bag upright. I wouldn’t recommend the material unless you have an industrial sewing machine. But it works! And I’m sure the neighbors appreciate the lower volume of the exhaust, compared to running it on a hose and muffs

 

[Ky Grady]

Run mine in a Rubbermaid 100 gal water trough left over from my horse riding days.

 

[RussGW270]

What is the prop part sitting above the water line?

 

[seasick]

looks like a bolt on kicker to me.

 

[DennisG01]

What is the prop part sitting above the water line?

It's similar to a JATO rocket (Jet Assisted Take Off) that some heavy planes/jets use to get off the ground when there is limited runway space. It helps the boat get onto plane faster. Either that, or it's a trolling motor.

 

[wrxhoon]

Bolt on electric trolling?

 

[leeccoll]

Naw,

It's a used prop from the Hellraiser movies Ky picked up for cheap on E bay.

 

[DennisG01]

Oh, KY Jelly... err... I mean "Grady"... your engine pees like an 80-year old man.

 

[glacierbaze]

I didn't even realize that his motor was running.

 

[Ky Grady]

You guys are so funny.

Minn-Kota EM80 trolling motor, used when the wind dies on Santee. Gotta be moving to catch fish. And for the low flow guys, that pic was taken early in my ownership of the boat. I've since cleaned out her tubes and changed out pumps and housings and got her peeing much better. The Yamaha's don't have a strong pee stream to start with, but it's more steady than what that pic captured.