Water is not beeing sucked up... 2003 Mercruiser 350

Hey everyone, im pretty new to the boating scene. With my boat sitting on the trailer and a water hose hooked up, i noticed its not sucking the water up into the motor when running and eventually it will overheat. Im very mechanically inclined and want to see if i can tackle/troubshoot this myself. Ived searched online and the impeller seems to be on topic. Any ideas? Motor has about 300 hours on it.

Thanks.

Re: Water is not beeing sucked up... 03 Mercruiser 350

What drive system do you have?

Re: Water is not beeing sucked up... 03 Mercruiser 350

Ya what drive, Alpha or Bravo, and what kind of muffs are you using? Where is the water going, just dumping out of the muffs, or is it actually going through the engine and out the exhaust ports in transom assembly or through the prop?

Re: Water is not beeing sucked up... 03 Mercruiser 350

I believe its a Bravo. Not sure on the brand of muffs, but they look like big earphones and the shape of the actual ear covers are rectangular. I have them clamped on nicely covering the intake holes, and the water just comes out from the sides of the muffs. Engine runs strong until temps get up and then i turn it off. Water pressure coming from the garden hose is good.

Re: Water is not beeing sucked up... 03 Mercruiser 350

Do you have the drive trimmed down ("IN") all the way?

If the drive is in the "Trailer" position, the hose between the drive and engine can get pinched.

Is there any water coming out of either of the idle ports on the transom or the prop?

Re: Water is not beeing sucked up... 03 Mercruiser 350

Hmmm I don't remeber where the trim was set at.. but ill check.

I didn't see any water at all coming from those ports.

Re: Water is not beeing sucked up... 03 Mercruiser 350

if it is a Bravo as he states it has a belt driven water pump, undo the hose at the pump and check for flow from the drive, then check belt tension and replace that 3 yr old impeller. IMO

Re: Water is not beeing sucked up... 03 Mercruiser 350

If the waterpump is in the same location as if this was a regular car/truck engine, then yes its belt driven. So the waterpump actually does all the sucking? Again this is my first time with boats so be nice.

Thanks

Re: Water is not beeing sucked up... 03 Mercruiser 350

There are two types of systems.

One type has a water pump impellor in the outdrive that SUCKS water thru it and pushes it to the thermostat housing and then thru the motor and thrn thru the engine water pump (basically)

The other type is a stand alone water pump housing with the impeller inside and is driven by the belt system on the front of the engine (NOT TO BE CONFUSED WITH THE MOTOR WATER PUMP)

Both systems suck water and push water.

Most alpha out drives have a impeller in the outdrive.

ALL BRAVO'S do not have a impeller in the out drive and use a stand alone belt driven housing/assembly.

NOT ALL BRAVO'S suck the water thru the outdrive. Some use a water pick up either thru thr boat floor or a pick up off the back bottom of the transom.

YOU NEED TO DETERMINE WHAT CONFIGURATION YOU HAVE

Either way the fact that the motor has been run with NO water wether it be because the impeller is allready bad or not you now need a new impeller........

Re: Water is not beeing sucked up... 03 Mercruiser 350

Hey thanks for all the info. When i was checking things out, i noticed on the motor there is the regular waterpump(like a car/truck) that bolts to the block thats belt driven, but then i notice another pump that has big coolant/water hoses going to it that sits on the lower left of the belt system in front of the motor... not really attached on the motor but more of an accessory pump.

Here is what my motor looks like... very simliar to this...
http://www.boattest.com/images-gallery/photos/Seacore350MAG.jpg

Here is a actual pic of my motor... its not the best but the only one i have...

Re: Water is not beeing sucked up... 03 Mercruiser 350

Ok the belt driven pump is the raw water pump, follow the hose to the transom or to the inlet.

So now you know if the water comes in thru the drive.

Take the hose off the other side of the pump, not the side that goes to the inlet, or drive.

Put water to the inlet , be it that you put the boat in the water or hook up a hose.

Start the motor for 3 seconds does water make it out the hose ?

If not then you know the blockage is before the pump.

Or the impeller is gone in the pump.

The blockage could be in the inlet of the drive or the fitting that goes thru the hull called a thru hull fitting.

I am trying to be as simple in my post as i can don;t think i am posting thinking your a idiot. Just someone who does not know yet. I believe you will know cause you will educate yourself.

Also untill i know that he person i am trying to educate knows stuff i post or speak to them the same way.

Ok say you find no water coming out the hose, you will have to check the pump, remove and open it, there are free d/l manuals for you to d/l here at a different spot on the website.

However it is very simple with simple tools to open the pump.

See if you have the vanes still on the impeller, or they broke off and are blocking the pump.

If not then you must follow the hose to the next connection be it a heat exchanger, or the t-stat housing.

Check the t-stat, see that might be frozen closed.

Post when you get to that point maybe the vanes are in there.

We will go from there, and hopefully you found something.

Good luck and keep your chin up you are not the first newbie i and others here have brokin in.

Re: Water is not beeing sucked up... 03 Mercruiser 350

OK, first, you have a bravo drive with a fuel injected engine which means you have the brass bodied raw water pump. It is very difficult to get this pump to pull water off of the garden hose. You have to actually hold the muffs against the drive tight while someone else fires the engine and raises the rpm's slightly (1500) to get this pump going. You will know when it starts pulling water.

Second, if you ran the engine long enough to have the over heat alarm sound, the pump impeller is finished.

Third, when you remove the whole pump from the engine and remove the back cover to change the impeller, assuming it is the brass pump, you will need to sand down the back cover until it is almost smooth. It will look like a worn brake rotor off of a car from the impeller wearing on it. If you do not smooth the cover, the new impeller will not pump a drop.

47-862232A2 Impeller part number

Re: Water is not beeing sucked up... 03 Mercruiser 350

Possible Brass pump!

Re: Water is not beeing sucked up... 03 Mercruiser 350

Quadruple confirmation of raw water pump needing attention. In trying to read between the lines I am assuming that this boat is something you bought used maybe this year or last year (you say you are new to the boating scene)? Do you do your own work on it or do you take it to a shop? If you do your own work, and this is a new-to-you vessel, and you don't have detailed maintenance records, then my friend you must do the following:

Replace every rubber part; hoses, belts, impellers, etc. on both the engine and the drive. New bellows on the drive. Grease the ujoint.
New cap, rotor, wires and plugs.
New water circulating pump. New thermostat.
Change the oil and filter, power steering fluid if fitted, and coolant if closed cooling. New fuel filter/separator.
Inspect motor mounts, tighten as needed, grease up exposed threads on adjusters.
Spot treat and touch up paint any rusty areas
Check, clean and re tighten all electrical connections, pay attention to the grounds and hot feeds especially.

This will get you back to home plate as far as the engine's health and well being are concerned and give you a starting point for all your future maintenance. Keep records. If it is a 2003 model boat, it is well past due for all of this.

Re: Water is not beeing sucked up... 03 Mercruiser 350

Thanks for the fast responses guys... i havent had any time to get any updates.. but either today or 2marrow i will get in there. I will definitly take pictures so you guys can help me identify some parts.

First i have to check where my Trim was set at.

Docksidemarineservices - i will defiintly try this since i had nobody holding the muffs down tight.. and ill also rev it up alittle.

chiefalen - if everything else checks out ok ill go ahead and perform these steps. Im pretty sure ill recognize most of the parts you said, but again ill have a camera just incase i get lost. I definitly need to snag a repair manual. Any good brands or sites that have them??

o2batsea - real new to the boat scene, i used to me an auto technician so i should be ok with working on the motor. I want to try and do most of repairs myself just to learn more about it. After i can run it safely to operating temperatures, then trust me, i will take care of the major maintence.. i dont want to be stranded while at sea

Your impeller is probably toast but like Dockside said, you have to apply some pressure to the muffs. Personally, I don't like the rectangular ones. I find the round ones are much more plyable and hug the housing better, making for a tighter fit which helps the water get to the pump faster. If you take the pump off, mark the position each hose goes to.

.. been alittle sick recently... ill try and keep this thread updated.. thanks.

Personally, I won't run the belt driven raw water pumps on a garden hose setup at anything above idle....they have much more flow capacity than a normal garden hose can deliver, even with city water pressure.

Sorry for late reply everyone, boat is at my parents house and its hard to find time to swing by. I took some pics the other day just to see what tools i need and i will probably stop by 2marrow. Honestly it looks very tight in the engine compartment, i hope i get some room to work.. im used to tight places, but this, i cant really see what size bolts/nuts are there... but ill do my best.

Here are some quick pics..

I know, pics arent the greatest, but i coudnt really get in there

Aaah nice and tight...it's a beautiful thing. Don't we just love those!! I'm talking about the location of the pumps guys!!

.... plans changed and i didnt make it by today... but yeah, its reaaal tight, i coudnt even tell what size sockets i need

Ahh thank you sir,,, that helps alot .

Quick question, in my pictures, what are those blue tabs? Looks like they can be turned?

Thanks again, i will try and get to it today.

They look like the drain plugs, to drain the raw water for winterization.

blue tabs r manifold drains thats what they r on mine