Is it safe to start mercruiser I/O out of the water?

[toolman4]

New to boating and was wondering if this hurts anything and how long can you run it to check motor for leaks and such?

 

[truckermatt]

Re: Is it safe to start mercruiser I/O out of the water?

if you have it hooked to water.... then you can idle for a while.

 

[Bucks45]

Re: Is it safe to start mercruiser I/O out of the water?

Sure it is. Just make sure that you use muffs and don't take the engine much over idle. Check to make sure water is coming out of the exhaust ports (to ensure your impeller is good). Keep an eye on your temp gauge.

 

[a70eliminator]

Re: Is it safe to start mercruiser I/O out of the water?

Hi welcome to the forum... I guess you are a newbee! NEVER start the engine with a dry impeller, you cannot run the motor for even 10 seconds without water, you need a garden hose hookup, they're cheap get them about anywhere.

 

[180shabah]

Re: Is it safe to start mercruiser I/O out of the water?

Yup, with muffs it should idle till you run our of gas....

 

[toolman4]

Re: Is it safe to start mercruiser I/O out of the water?

Ok what are muffs, my girlfriend is wondering hinting anatomy ha, AND what happens when you do run it longer with out the suggested stuff?

 

[AguaSki]

Re: Is it safe to start mercruiser I/O out of the water?

what happens when you do run it longer with out the suggested stuff?

Your rubber impeller is stuffed into a stainless steel cup. When the impeller spins the blades rub against the cup. This is not a big deal if water is present, but if the impeller is dry friction heat will quickly develop and ruin your impeller. Once the impeller is ruined you run the risk of overheating your motor. I am a visual person so this was hard for me to understand, but after I rebuilt my first water pump it was crystal clear to me why you don't want run the motor for even a few seconds without a source of water.

 

[smokeonthewater]

Re: Is it safe to start mercruiser I/O out of the water?

also it is not a time limit.... do not even start the engine for an instant without water and if you have change the impeller before ever running it again

 

[ziggy]

Re: Is it safe to start mercruiser I/O out of the water?

Ok what are muffs

muffs.. http://www.iboats.com/Boat-Parts-Ac..._category.f--searched.1--**********.016240967

why not to run w/o water flow... http://www.boatfix.com/merc/Bullet/87/87_14.pdf look at page 2..

 

[Rscardina]

Re: Is it safe to start mercruiser I/O out of the water?

toolman.. muffs? hahaha, yup that is the term for a bent piece of metal with a 2 suction cup looking thing that mount on your lower unit. One side has a garden hose connection that you use to give the engine water.

secondly, just in line with your propeller in the housing on the lower unit there are some small holes (vertical in direction) on either side...the suction cup (muffs) go over these holes. the holes are the water intakes to feed the pump that pushes the water into the engine.

once you have watre running for a few seconds (turn up the spiget) then you can start the engine.

as previous posts mention DO NOT, EVER, no matter how much you feel the urge..start without water...you will damage the rubber impellar (you cant see it) inside the lower unit..

look up rabbit eras, or flushing muffs for marine engines..you will see apicture and will become clear to you..

good luck!

PS..once you have the muffs on and water running...you can run the engine as long as you want..but as mentioned DO not rev it up too high..you can throw rods in the engine...not good..

 

[Doug N.]

Re: Is it safe to start mercruiser I/O out of the water?

Turn the water on all the way once you have the muffs installed! I only turned the faucet on part way and the motor sucked the hose dry...resulting in the need to replace the impeller. No wonder they call it "paying the stupid tax." I only pay the tax one mistake at a time.

 

[Silvertip]

Re: Is it safe to start mercruiser I/O out of the water?

An engine is water cooled. Even if the engine has whats called a closed cooling system, it uses a water-to-water heat exchanger so an external water source is required in either design. No cooling water - overheated engine, damaged water pump impeller and well -- a big dent in your wallet. Can't make it any simpler than that. And if your boat has a raw water cooling system and you attempted to run it, without the external source of cooling water, what would you expect to leak?

 

[mattb1974]

Re: Is it safe to start mercruiser I/O out of the water?

ALSO... Dont run your engine, even in neutral, with the drive tilted up.

 

[Bob's Garage]

Re: Is it safe to start mercruiser I/O out of the water?

One other thing to remember - DO NOT RUN THE ENGINE IN GEAR. The potential for injury is very high, and the injury can be extreme.

The prop may still spin when out of the water, and at idle, but it will be from the energy of the engine being transfered to the prop, without direct engagement.

BE VERY CAREFUL OF ANYONE STANDING AROUND, MAKE SURE THEY ARE NOT NEAR THE OUTDRIVE. YOU GET NO 2ND CHANCES, THE PROP IS VERY SHARP. PEOPLE HAVE BEEN CUT JUST FROM BUMPING INTO A PROP AT REST.

As a newbie you should be afraid of the outdrive until you become more experienced.

Not everyone is going to agree with my advise, but you cannot get hurt by following it. Nor can anyone else.

 

[Philster]

Re: Is it safe to start mercruiser I/O out of the water?

ALSO... Dont run your engine, even in neutral, with the drive tilted up.

You can run the engine with the drive tilted up, but only as far up as the TRIM button will take it.

You shouldn't run the engine when the drive is in a position that exceeds the trim limit, which is accomplished via the TRAILER trim button. I use 'should' or 'shouldn't' alot, because you can do whatever the heck you wanna do in the end. ...but it's a bad habit to have the drive up via the TRAILER trim function unless you are... well... trailering.

Muffs: They look like ear muffs, hence the name.

Impeller: rubber piece with wings that spins and moves water. Without water, it's toast. You need it.

Can you run the engine without water? The answer is yes. Should you? The answer is no, if you don't want to toast an otherwise good part.

 

[ryanr623]

Re: Is it safe to start mercruiser I/O out of the water?

muffs.. http://www.iboats.com/Boat-Parts-Ac..._category.f--searched.1--**********.016240967

why not to run w/o water flow... http://www.boatfix.com/merc/Bullet/87/87_14.pdf look at page 2..

I cant believe that running the engine at 1500 rpm for sixty seconds only does that amount of damage. It is a mercruiser bulletin, but most peoples would be toast after 30 seconds, let alone 60 seconds I would think.

 

[toolman4]

Re: Is it safe to start mercruiser I/O out of the water?

Great info! Muffs are on the list. On to my electical problem.

 

[toolman4]

Re: Is it safe to start mercruiser I/O out of the water?

Couple more questions. Can you drop the motor in like a large tote with the propeller submerged and be ok for tuning? So when the engine is on, even with the advanced throttle control and not in gear, the impeller is turning right? Is it much work to look at the impeller for general service to make sure it looks like it is supposed to?

 

[180shabah]

Re: Is it safe to start mercruiser I/O out of the water?

Impellers are not inspected, they get replaced.

You have to split the drive to access the seawater pump. If you intend to DIY, you NEED a factory service manual - one for the drive, one for the engine.

 

[toolman4]

Re: Is it safe to start mercruiser I/O out of the water?

So as long as the impeller is in water, like in a big tote, (waiting for muffs) it would be okay to run the motor without the drive?