77 sterndrive & washdown pump

[user-name]

I recently bought a a 77 omc everything sweet so far.

On my volvo penta I tapped in to the raw water line for my washdown pump.

Is this possible with the OMC Without the motor running ?
I know it will work with motor running
I know the raw water pump is in the leg not like the VP.

When I hook up a garden hose to the raw water line water flows out the water intake on the leg.
Motor not running.

I figure It cant hunt to ask.

Thank you
Bob

 

[bruceb58]

Re: 77 sterndrive & washdown pump

On my volvo penta I tapped in to the raw water line for my washdown pump.

That's sounds like a not too smart thing to do(That's as nice as I can say it).

Get a thru hull pump for your wash down. That's what I have.

 

[Scott Danforth]

Re: 77 sterndrive & washdown pump

are you pumping water in, or taking water out?

OMC had a water flushing port as an option. it was a tapped bearing cap for the starboard side. you can add water with the motor running, or not running

however if you are taking water - there is not any excess water flow in the raw water circuit. I would not plumb into it for any reason to take water from the circuit. you are basically causing an over-heat of your motor.

if this is the case, as Bruce indicated, use a separate thru hull pickup.

 

[user-name]

Re: 77 sterndrive & washdown pump

That's sounds like a not too smart thing to do(That's as nice as I can say it).

Get a thru hull pump for your wash down. That's what I have.

The VP Is basicly a thru hull type system except it goes though the sheild and down the leg. the raw water pump is on the motor.
if the seals go bad in the leg of the VP and you suck air the easy way to fix it is drill o hole in the bottom of the hull and put a bronze skimmer in it like a inboard .

If and when the raw water pump goes bad on the OMC I will NOT waste my time fixing it.
I will be putting a VP RW pump on the the OMC 302 motor. And mount a bronze skimmer

BTW Ill be testing my question later today.

 

[user-name]

Re: 77 sterndrive & washdown pump

are you pumping water in, or taking water out?

OMC had a water flushing port as an option. it was a tapped bearing cap for the starboard side. you can add water with the motor running, or not running

however if you are taking water - there is not any excess water flow in the raw water circuit. I would not plumb into it for any reason to take water from the circuit. you are basically causing an over-heat of your motor.

if this is the case, as Bruce indicated, use a separate thru hull pickup.

I was asking if the washdown pump could pull water though the OMC leg if the motor is not running.
Also this is a washdown pump used to wash blood off the deck. while using the kicker motor.

 

[bruceb58]

Re: 77 sterndrive & washdown pump

Ok...now I see what you are saying. You are going to share the line with a separate pump when the engine is NOT running.

 

[bruceb58]

Re: 77 sterndrive & washdown pump

On your new OMC it won't work obviously with the impeller in the leg. No water can flow past the impeller even with the most powerful pump. You would also have massive air leaks on the engine side.

 

[user-name]

Re: 77 sterndrive & washdown pump

On your new OMC it won't work obviously with the impeller in the leg. No water can flow past the impeller even with the most powerful pump. You would also have massive air leaks on the engine side.

Ok thats a buyable answer.

Now let me throw results of test 1 at you.

Motor not running I remove the raw water line from motor.

Attach a garden hose to the line so now water goes to the leg in other words reverse. water does flow out of the leg water intake. so in other words water goes past the pump Impeller.

That leads me it to thinking it could be done.

 

[user-name]

Re: 77 sterndrive & washdown pump

ok...now i see what you are saying. You are going to share the line with a separate pump when the engine is not running.

yes yes

 

[Scott Danforth]

Re: 77 sterndrive & washdown pump

water pressure from the hose is about 60psi. it will leak past the impeller under pressure, however the suction side of a pump will not pull thru the impeller without the impeller turning.

 

[user-name]

Re: 77 sterndrive & washdown pump

water pressure from the hose is about 60psi. it will leak past the impeller under pressure, however the suction side of a pump will not pull thru the impeller without the impeller turning.

Thanks that's what i was thinking also.

I just didn't want to put a thru hull in boat yet.

 

[user-name]

Re: 77 sterndrive & washdown pump

I just didn't want to put a thru hull in boat yet.

I better rephrase that I have very limited room with the layout of this boat to get a thru hull fitting in the transom and be deep enough.

The bronze skimmer is my best bet, but I dont want to do that yet till I put the boat on a different trailer it on a temporary (Painted)trailer at this time.

 

[Scott Danforth]

Re: 77 sterndrive & washdown pump

if your using it only while at rest and not on plane, you can place it higher on the transom, just below the water line

 

[user-name]

Re: 77 sterndrive & washdown pump

if your using it only while at rest and not on plane, you can place it higher on the transom, just below the water line

I wish i could.
Its a different transom design that most boats with a lot of stuff already on it.
The BIG omc hole doesn't help.

only way i could make it up high like a bilge out using this Amazon.com: Attwood Corporation 3877-3 Thru-Hull Connector: Automotive and a water pipe down to water.