Mercruiser 57 V8 water flow problem

"Hello,
I have a Mercruiser 5

"Hello,
I have a Mercruiser 5.7 V8 engine with a Alpha 1 sterndrive (the boat has been standing for a few years)

Could you help me plaease .... I can not get water to flow through the system and out the exhausts.

I have tryed with bunny ears and standing the sterndrive in a tub of water and also a hose pipe going direct into the water pick up pipe

The engine runs fine but all the water pipes are empty and alot of steam comes out the exhausts

What would be the first thing to check/replace?

(at the moment i am bypass the SternDrive, have the hose pipe going into the engine pick up side)

Thank you for any help"

"Ayuh,...

Replace the Impel

"Ayuh,...

Replace the Impeller,+ whatever else is Trashed in the raw water pump in the outdrive...
And backflush from the T-Stat housing back to the outdrive to flush the Junk out...

Then we can figure out If you have any Other Problems..."

"Thanks for Reply Bondo

You

"Thanks for Reply Bondo

You say replace the impeller ect in the outdrive

But at the moment i am bypassing the outdrive with a hose going direct into the engine water pipe pick up.......doing it this way shouldnt the water pump on the engine fill the system and eject water out the exhausts???

Also i have undone the bung ontop of the engine water pump and filled it with water , when the engine is running it pushes water out the bung hole, so the water pump must be doing something??



"

"[b]"But at the moment i a

""But at the moment i am bypassing the outdrive with a hose going direct into the engine water pipe pick up......."

Ayuh,... Where, Exactly are you plumbing in,..??

The In-coming line goes to the T-Stat Housing...
From there it goes either to the manifolds, or the motor/ water circulating pump...

Click here,+ follow the path to the factory Manuals,..
Then download the 1s for your motor,+ drive....
They should clear up most of your Questions..."

Running the engine w/o water t

Running the engine w/o water to the OD impeller fries it; replace it now or overheat later. Check the water circulating pump; shaft may be broken or belt slipping. Change the thermostat too.

Check the exhaust shutters; they may have been fried by the exhaust flame.

"Thanks for the Replys

Mayb

"Thanks for the Replys

Maybe i dont explain it correct?

The boat is OUT the water , instead of putting bunny ears on the outdrive i am connecting a garden hose pipe directly into the Engine pick up water pipe.... (how can this fry the OD impeller? the out drive is not running)

I am only running the engine to check the condition of the engine"

"If the engine is running, the

"If the engine is running, the shaft driving the water pump is turning and the rubber impeller is running dry and is probably a gummy mess inside the pump housing now. You cannot run an I/O setup without water running through the leg. To be safe you would have to have the muffs on and water hooked up to them at the same time as running water direct to the motor."

Check the circulating pump on

Check the circulating pump on the front of the engine. It is connected with a pully. Even though it is turning does not mean that the impeller within the circ pump is turning there fore no water exitingthe engine.( Look and see if there is water weeping from below the circ pump. If so there is the problem.) At this point you have destroyed the water pump in the drive. By running the engine out of the water not using the muffs through the dive you have done damage to the water pump within the drive.I must be replaced. You may also have collapsed water shuters that are not allowing the water to leave the engine.Can you place your hands on top of the risers? if not then there may be a problem there. Hope that this helps

""The boat is OUT the wate

""The boat is OUT the water , instead of putting bunny ears on the outdrive i am connecting a garden hose pipe directly into the Engine pick up water pipe.... (how can this fry the OD impeller? the out drive is not running)"


Ayuh,... Once again,....
Where, Exactly are you plumbing in,..??
What water pipe, Where,..??

And, as noted,...
Anytime the crankshaft is turning,..
The Outdrive,+ Impeller is Also turning....
At this point,.. You probably need a new Complete Impeller,+ it's Housings..."

"Paul,
Are you saying that

"Paul,
Are you saying that the outdive has been removed from the boat, and you have connected a garden hose into the bell housing? If this is so then the drive is not involved at this point. Some areas to look at
1. Risers are blocked
2. Thermostat no opening
3.Watter shutters are not operational
4.Circ pump not operational

Open the two(2) pet cocks on the bottom of the engine( one one the port side one on the starboard side.) Using a piece of a coat hanger poke into each so tha any sand or what else is in there is removed. See if water exits. No water out no water in. run your garden hose with the engine off and watch and see when clear water exits the system. ( keep poking each side untill this happens.) Close each pet,Remove the hose to each riser and manifold see if they are clogged. Remone the hose from the exiting port of the thermostat housing and see if it is collapsed(You can also tell by squeezing the hose if it remains collapsed you have a problem there.)Hope this helps"