Running 5.0 Mercruiser MPI with Bravo 3 on earmuffs

Serenity

I hear so many conflicting theories. Can one run 5.0 Mercruisers with Bravo 3 outdrives on earmuffs? Just to see if engines come up to temperature, checking water pump, no leaks etc before the boat is put back in the water after sitting all winter. Not to rev but to just idle.

frenchship

I used mine all the time, even Mercruiser shop manual show how to used them . Do not rev the engines with the **** on

212rowboat

Does he not have an engine mounted sea pump? Do some draw through foot while others don't? Does one feed engine and another feed risers? How exactly is a bIII set up?

Handymans342

I still cant figure out my B2s but I know water goes thru them. 

JoeStang

Yep, I run the antifreeze though the earmutts every fall. Mine won't let me rev it anyways, it will only idle. Prob because lower water flow from hose vs being in water.

Serenity

Thank you Joe. That is what I figured. I just want to be able to start them up and run before the boat goes in the water. How bad would that be when the lift puts the boat in and motors will not start.

craigswardmtb

Merc recommends running at slightly above idle when on muffs, 12-1300 rpms if I recall.  The B3's suck some serious H2O, so I usually tape my muffs to the drive to keep as much water going through it as possible.  Also use a quality hose.  Some of those flimsy garden hoses will get sucked flat.

Dream_Inn

I just replied to the last post you had going on this.  I have ran both B3s and B2s on muffs with no issues whatsoever.  As craig said, they just need to be on tight.  Also as mentioned a good hose so you don't get kinks.  I only do it in the fall on the lift before I ran pink stuff thru.  In spring I just lower the lift enough to run it and check it all out.

Weber

I run my bravo 3's on the muffs on spring start up before splash, just to make sure everything is going to start when the lift lowers her down.

Never had an issue.

frenchship

212 rowboat.
if  you have interest how the bravo 111 and 5.0 MPI  water flow goes from the muffs to the rest of the engine , I can post pictures from the Mercruiser original shop manuals
Paul

212rowboat

Would be awesome, sir!!! I know engines alright, but what's south of them is a mystery, and I suspect witchcraft is afoot.

frenchship

Here are some pictures from the shop manual.

212rowboat

awesome!!!!  some, though, feed from a through-hull, right? 

frenchship

Yes they do. And some seems to have both why I don't know.......

06Rinker270

How do you know for sure that the water is properly running through the engine when using muffs?  I am doing this for the first time this weekend before launch.  

Any other steps to complete before firing up once the water is running properly.  

howardrams

I had contacted Mercruiser due to the wide variety they discuss in the service manual, causing confusion, and the answer was Yes the common earmuffs are adequate at idle speed on the B3.  Make sure all hose clamps are tight, blue drain plugs are in.  Check for leaking in the engine compartment after you fire up.  Assuming your temperature gauge was working, it should gradually come up but they go back down once your thermostat opens if you leave it run long enough.  You'll notice water warmed by the exhaust coming out by the prop.

06Rinker270

Appreciate it @howardrams.  If the engine is winterized properly all the blue drain plugs should be in correct?

nonetheless, will still keep an eye for leaks in engine. 

craigswardmtb

correct to plugs in during the winter, otherwise the antifreeze would drain out.

frenchship

Here what an expert had to say about leaving the blue plug in for the winter.

• Alswagg Posts: 378Member ✭✭✭

  October 2013

  You had better not be using Green or Orange antifreeze in these raw water cooled engines!  If you do, be sure to collect every single drop in the spring and do not let it go into the water.  Toxic antifreeze can kill fish and other species which live in the water.  Use only Non toxic antifreeze pink or purple, for flushing raw water cooled engines.  We pull every plug, and flush with Non toxic Marine antifreeze. Yes we allow this Marine antifreeze to drain back out.  No liquid, no ice, period.  Al

   Flag  Quote ·  Off Topic  Insightful  Disagree  Agree  2Like  Awesome  LOL

howardrams

Agreed.  We don't need the old automotive ethylene glycol in our waters.

frenchship

The advice was more in regards of leaving the blue plugs out during winter .

212rowboat

my blue plugs go in a baggie, and then a cup holder at the helm where I can't miss them before turning the key, over the winter hold-up.  the notion of leaving them out is that the ice has somewhere to go/grow as opposed to being captured and expanding within the block- cracking it.  

the downside of removing all the treated water and leaving the blue plugs out is that scale and rust can form on internals- to include the circulation pump... if you're in salt water and don't flush that thing VERY well, it stands a good chance of bonding to the housing and breaking free in the spring when you attempt to start it up. 

 

06Rinker270

So then if you take the drain plugs out there is no pink antifreeze in the engine?  And that's ok?  Do you run the antifreeze through the engine and then drain?  I believe all my plugs are in and the marina winterized the engine.  Thanks a lot everyone.

212rowboat

there is going to be some residual water in there.. you can't get it all out.  if you trap the water by using the plugs, and if it gets cold, you're gonna want to have a good concentrate of antifreeze in there...

i use the antifreeze (pink), and then I still lose the plugs over the winter... i'm not real worried about freezing, though, because where I'm at. 

06Rinker270

But doesn't taking the plugs out get rid all all the antifreeze? Or it sits where that residual water hides

212rowboat

Yeah...exactly... You're basically hoping a good mix of antifreeze puddles in knooks and crannies the just ol plain water would hide.

06Rinker270

Then why not run plenty antifreeze throughout knowing the water has mixed with the antifreeze just as if you drain it by taking plugs out?

rasbury

I run mine on the muffs but only when I need to- there are several different water flow systems and routing, depending on if you have a 1/2 closed loop or not which mine does.  Then, depending on if you have cold risers or warm risers (still don't understand the difference on those). I have a raw water pump that draws from both the foot and a thru hull- plus an auto style pump for the closed cooling system. Also, have read that when you put the muffs on to make sure the foot is in the down position, not sure if it makes a difference buy why take a chance- only takes a few seconds to potentially burn up that raw water impeller which is a real bugger to change!

Dream_Inn

I think it's all a matter of preference and opinions at this point.  I've done it both ways, but I've left the plugs in more times than not, and that is what I've recently done.  Now, only my risers & heat exchangers is raw water, but I leave the pink in.  I only use 2-3 gallons per engine & I also use the hand pump to get the water out before I put pink in there.  So when I'm done, it is definitely concentrated pink!  I also leave it because it helps with corrosion (as long as you buy the correct stuff for that).  OK, enough of winterization talk, it is spring and I've enjoyed 2 full weekends of staying out on the boat!

rasbury

and PS, close the thru hull sea **** before you try the muffs or you will water the ground.....if you have thru hull!

rasbury

and do you really want me to show you all again how I de winterize my boat?