Running boat on land with no prop?

[Lou C]

 

[muc]

back to original question ,is it ok to run boat (with muffs) with no prop on

Yes, MerCruiser recommends that you remove the prop anytime the out drive is run out of the water.

But please don’t run a new/rebuilt engine for very long without a load. That will glaze the cylinder walls.

 

[muc]

View attachment 370219

Yes, yes, yes. These are the best muffs you can buy For your MerCruiiser. The only place they don’t work, is when running wide open on a dyno. For that you need to feed water in both sides.

 

[muc]

Trust me muc, once these guys have their minds made up no amount of factual information is going to sway them.

I'm with you on this one, I have much experience in the field and can confirm all the facts you are posting. The problem with this forum is when one is pragmatic it increases the disinformation from others.....

What concerns/worries me is that some of these people have posted good info in other threads. They have some high post counts so if someone was to come across this thread, they might actually believe this misinformation.

 

[Lou C]

back to original question ,is it ok to run boat (with muffs) with no prop on

yes

 

[nola mike]

What concerns/worries me is that some of these people have posted good info in other threads. They have some high post counts so if someone was to come across this thread, they might actually believe this misinformation.

Well, if op has been running in a trough for 50 minutes, his impeller should be cooked and overheating by now, right?

 

[muc]

@muc, I will put $100 that says if you run that impeller dry, and try to draw water 2.4 meters, you will turn the impeller to a burnt little crisp long before water ever gets to it. look at my profile on linked in and look to see whom I am connected to at VolvoPenta/Merc/PCM/Cummins/John Deere/Cat/etc.

I can only go by what the lab testing results were and how they were communicated back to us

Brunswick even posts a few pages in their manuals on what happens to the impeller after 45 seconds of not being submerged when operating.

I’m guessing they will lift water that high at least once, but I sure wouldn’t try it to many times.

This post is about a high pressure/low volume style pump vs the Gen2 low pressure/high volume.
And once again I’m guessing here. If you look at what style pumps are used when they are engine mounted. They are almost always high pressure/low volume style pumps. This makes me think a high pressure/ low volume pump will lift better.

Per the O.P.s picture, the water level is over the anti-ventilation plate. So he’s only asking this pump to lift less then 2”. Something it should easily do.

Yes, all the manuals will tell you to not run the pump dry for more than 15 seconds. But in this situation we are only talking about less than one second.

Some people think muffs will push water a long way. But in my experience if you have a Bravo or Volvo out of the water and hook up muffs with the garden hose on full. The water won’t make it to the pump, even with the intake hose removed from the pump.

 

[Rick Stephens]

What concerns/worries me is that some of these people have posted good info in other threads. They have some high post counts so if someone was to come across this thread, they might actually believe this misinformation.

Ya know muc, you n dubs can have at it here. Better count on spending more time since this yokel will be off doing something else. Bye.

 

[poconojoe]

I don't get all the arguments.
My thought is why take the chance?

It is way more catastrophic when these engines overheat than it is for our land vehicle engines and it can happen real quick, in a matter of seconds.

So, again, why take the chance?
Why is the OP so against using muffs?
Plus, it seems like so much more work to fill a tank with water, get your drive positioned in it, keep exchanging the hot water for cool water and keep the thing full while it's running.

I guess some people just have a need to buck the system, take chances, make things more complicated and work harder at something that is quite simple. Clamp on the muffs, turn on the hose, start your engine. Seems simple to me.

Whatever.....it's his boat, let him do as he pleases. He's going to do it anyway.

 

[dubs283]

What concerns/worries me is that some of these people have posted good info in other threads. They have some high post counts so if someone was to come across this thread, they might actually believe this misinformation.

Agreed

What really gets me confused is how in one thread you'll see some knowledgeable folks post that you must adhere 100% to oem recommendations, no exceptions and the next thread they're bashing manufacturer recommendations and say to not follow procedure and to not waste money on quality parts

Maybe it's a gut feeling they have?

 

[newtoboat101]

OP here,i am not against muffs at all ,my past experience ,which aint much, with muffs is that the muffs never sit on my lower outdrive correct ,gaps in the muff to outdrive letting water out and air in , water temp would fluctuate , and water exiting was weak flow and less volume ,and had to be monitored,but when i use tub ,when i start motor water is exiting almost imediately,with loose muffs i could take alot longer ,and constantly messing with muffs to get proper flow ,when i should be timing and tuning engine , i have listened to everyone opinion ,gonna go back to muffs ,the quicksilver ones,and not going to try and breakin on land will be breakin in next year,boats not ready for water yet ,and winter is closely approaching, I APPRECIATE ALL THE IN PUT ,didn't mean to start a feud on here ,just wanted to know if i can run out of water with no prop, that was really it. had boat 6 years (been working on it that long ),had boat out about 24 times, have turned to iboatsforum alot ,and i appreciate the high post people like ALLDODGE ,SCOTDANSFORTH, KEVIN STEPHENS, THE HAVE ALL HELPED WITH MY PROJECT ,so i usually listen to them ,especially the first 2 ,tho the second one is little gruff ,but has never steered me wrong thanx all on to my next issue with boat

 

[FORREST3]

Ya know muc, you n dubs can have at it here. Better count on spending more time since this yokel will be off doing something else. Bye.

I totally agree! Debate is good..Open minds are better..finality is rude!?

 

[poconojoe]

I totally agree! Debate is good..Open minds are better..finality is rude!?

Agree.
Debate is always good.
Hear all opinions and decide for yourself by using you brain and past experiences.
Lack of debate or recognition of other opinions is a major problem in this country as of late.

 

[Lou C]

If you get the muffs I posted your trouble with running on the hose, will be finished. They are the best that I've tried.
View attachment Cobra running on the water hose.MOV
Here they are on my OMC Cobra, the way to tell they are working well is the amount of water that is exhausting from right in front of the large anode on the lower unit.

 

[Bondo]

OP here,i am not against muffs at all ,my past experience ,which aint much, with muffs is that the muffs never sit on my lower outdrive correct ,gaps in the muff to outdrive letting water out and air in , water temp would fluctuate , and water exiting was weak flow and less volume ,and had to be monitored,but when i use tub ,when i start motor water is exiting almost imediately,with loose muffs i could take alot longer ,and constantly messing with muffs to get proper flow ,when i should be timing and tuning engine , i have listened to everyone opinion ,gonna go back to muffs ,the quicksilver ones,and not going to try and breakin on land will be breakin in next year,boats not ready for water yet ,and winter is closely approaching, I APPRECIATE ALL THE IN PUT ,didn't mean to start a feud on here ,just wanted to know if i can run out of water with no prop, that was really it. had boat 6 years (been working on it that long ),had boat out about 24 times, have turned to iboatsforum alot ,and i appreciate the high post people like ALLDODGE ,SCOTDANSFORTH, KEVIN STEPHENS, THE HAVE ALL HELPED WITH MY PROJECT ,so i usually listen to them ,especially the first 2 ,tho the second one is little gruff ,but has never steered me wrong thanx all on to my next issue with boat

Ayuh,.... Sounds like a good move,....

I post what has happened to Me,.....
I ain't a tech, though I've worked on alota boats,....

I treat our impeller pumps as flooded entry pumps, as without water, or something, their life is extremely short,....
Been there, seen that,....
I always use one of the several quality muffs I've got, water on full,... they leak alot, til the motor starts, 'n not at all at higher rpms,....
I don't think I've ever seen any pump that like to suck, without a prime,..... Push is what they're made for,....

Seein's NtB101 has brought us up to date, I think it's time to give this one a rest,.....