Sucking the flush hose closed
 

My boat likes to suck the flush hose closed. The water comes in from a 1 1/4 thru fiting through the coolers to the bravo raw water pump. From the raw water pump the water flows to the heat exchanger and then out through the risers. I close the trough fitting and then open up a valve to attach the garden hose.

It doesnt take much for the bravo raw water pump to suck the hose dry. With the factory systems is there anything to keep the hose from sucking dry. I have thought about attaching the garden hose without the hose washer so that air will get sucked in before the hose will suck closed. This will cause alot of water to spray but is better than replacing raw water pumps. Maybe if I reposition the water attach point to the transsom this would be the way to go? The water would leak on the transom but who cares?


Does any one else have problems sucking the hose dry?
Do I just need a better hose and more pressure. This will happen at idle power.

I've seen it happen too. More water pressure is what you need. A stiffer hose may help , but keep in mind it's still not supplying the water the Merc pump is sucking:(

Yup you need to get one of the industrial hoses. They are rigid enough that you will not pull the hose shut. Like has also been said if you can get the water flow up you will do better. You need flow not preasure.

Jon

This is my idea. Why not mount a transom adapter and leave the hose washer out. Alot of water and a little air is better than a closed hose.

Who sells a good transom hose adapter? What is the best?

Thanks

How about this? I have a water fill on my transom. It is a 1 1/4 type fitting with a 1/1/4 inch hose that fill my fresh water tank. Why not run a 1 1/4 inch hose to the valve that jpoins my 1 1/4 inch hose into my bravo style raw water pump. Put the hose in and crank it on full and let the water run into my bravo water water pump.

I have closed cooling so i am not concerned about water pressure in the engine. I just want enough water so that my impeller will not burn up and my engine will have some cooling.

Any thoughts?

thanks

How about solid 1 1/4 schd 40 from the water fill to the valve before my raw water pump. the water fill is about three feet above the raw water pump. Put the hose in open the valve and flush.

Is schedule 40 pipe too tacky for a flush system? I know it will not suck close.

Thanks

I bought some heavy wall 3/4" I.D. tygon tubing that I hook directly to a 3/4" copper city water line (I just remove the spigot and use a full size ball valve). I can run my engine to about 3000 rpm before it starts to suck the hose closed

REMEMBER IF YOU ARE USING A HOSE CONNECTED TO YOUR HOUSE IT IS FED FROM REDUCED LINES RUNNING THREW YOUR HOUSE AND FLOW VOLUME IS REDUCED TO MUCH. YOU WILL ONLY BE ABLE TO IDEAL MOTOR AT BEST. I USE A ACTUAL 3/4 FLOW INDUSTRIAL HOSE & FEED IT WITH CITY WATER FROM A 1" FEEDER. THIS WAY YOU WILL GET THE VOLUME YOU NEED TO RUN ONLY APPROX 2000 RPM. MAINTAINING FLOW VOLUME + WATER PRESSURE IS EVERYTHING!!!!! RON

I use a 1'' automive hose and a 5gallon drywall bucket with a hose fitting in the bottem of it. I let the garden hose fill the bucket as the engine runs. I also have to add water to the bucket as it runs. I fill some spare pales befour i start.

wildthing,

I have full closed cooling which should give my engine some protection.

Fred,

Maybe I should run a 1 1/4 line from my fresh water tank to the raw water intake manifold. This would give me a ten gallon headstart.

You need to remove the water pickup hose from the transom and shove the garden hose down it. Sucking the hose closed will immediately starve your pump for water, very bad thing. Doing it my way will never starve the pump for water, just add some air.

Dave

Dave

that is what I need to know. Shoving the garden hose down my water fill is much better than sucking the hose closed.

Thanks

Glad to help. I believe that is why I never need to replace impellers while most everyone else does.

Dave

The hose gets sucked flat when hooked to my Bravo but, the water stills keeps coming out the exhaust. I don't think that just because the hose is collapsing that it means the water is not getting through. The reason that the engine overheats at anything much above an idle is because, as someone has already said, the water is coming through your house and the hose bib on the house which is a huge restriction. Have you ever seen how small the hole is in one of those. Less than 1/2" unless you have an industrial ball valve which most of us don't. The volume of water getting to the hose is just not there to meet the demand of the Bravo style water pump. I don't see how a stiffer hose is going to help. Maybe I am missing something but, I don't think so. If someone can convince me that a hose that is collapsed by suction will cut off the water flow I am ready to be enlightened.

NEVER WORKED WITH CLOSED COOLING SORRY:confused:

Thats why they call them suction hoses. They have the strength to resist being sucked closed. Never tried to suck a milkshake through a straw? Same principal.

formula 31,

You have enlightened me. What you say makes sense. Wow! the knowledge you gain from OSO is amazing. :D :cool: