Taking on water after going fast

[Lars Gustafson]

Just purchased a 2001 Islandia Seadoo. Seems that the boat takes on water after going high speeds. Boat responds well to throttle and goes 40mph at 6000 rpms.....but when I slow down and after operating for awhile, it seems the boat has taken on water and feels heavy. Tach reads 4 to 5000 rpms and boat will then only go 15mph.... Thoughthave once left that water may have come in via the engine flush out hook up. (may it open....causing seawater to come out the flushout line during operation???) Checked out both bilge plugs which are both in good working order. Is there any other way water can be getting into the boat? Thanks in advance for your feedback.
Lars

 

[seadoosnipe]

Cooling system....?

I believe your going to find a leak in your cooling system somewhere because your water pressure builds as nozzle pressure builds. You may not see this leak at idle because of the lower cooling pressure.

There is a gasket for the expansion chamber and calibrated elbows at this plate where your cooling system first comes into the boat from the pump. The plate has two parts, the adapter and cover assembly. So, there is a possibility of a leak here.

I don't think water is coming in through your flush connector.

What to do....With the water hose hooked up to your engines flush out connection, start the water and motor. With the engine compartment open, use a mirror and flashlight looking for a leak near the base of the engine.

To simulate high pressure from your pump at high speeds, increase the flow of your water hose. I can't see in the drawing if you have a "tell-tale" line, but if you do, increase this water hose pressure till you see a pee stream about equal to what you see at full throttle.

You can also use a pressure gage connected to the top of your power head. At 5800 rpm, your pump should generate 13 to 17 psi. So, if you connect to a pressure gage, you can use it to simulate full throttle. Then, you'll want to use the mirror and flashlight once again to look for leaks.

 

[Lars Gustafson]

Thanks

Thanks for the quick reply! Will try out this test and report back. Engine appears to run fine (bit smokey when I first start it up, but it seems to go away once I run it for awhile.) Overall, happy with the boat design and feel of the boat. Thanks again for your reply, wish I could buy you a beer or two for your time.

 

[seadoosnipe]

Bilge siphon system?

I'm looking at winterize procedures for another member and I came across a chapter on the "bilge siphon feature" of the M-2 boats.

This system works like the bailers of a jet ski. You have a hose that is connected to the pump nozzle. The tube comes into the engine compartment and is routed to a clamp at the exhaust manifold to create a loop seal to keep the water from running back in once the boat is off plane.

This system is designed to work when the engine exceeds 3000 rpm.

If this hose is still attached but laying in the bilge of the engine compartment, then the water can flow in easily.

If it's hooked up correctly but you have electric bilge pumps, make sure this system is dis-connected and plugged.

To identify it, look for a clamp and hose on the exhaust manifold. If it's not being used, the manual states that it is coiled up at the clamp of the exhaust manifold. If it has been used or is in use, the end of the hose will be laying in the bilge and have some type strainer screen.

I was kinda of surprised when I ran across this chapter. Even more surprised to see a boat use this type of "vacuum" system. This system is used in ski's which is logical, there isn't much area to pump out, but in a boat?.....I'd have never thought it would be there.

There is also another option for the Mercury powered boats, that I was unaware of (finding info in the maintenance section. I am normally in the engine section). It's called the "water by-pass system" and is used to improve powerhead cooling at idle speed. This is an option; not something connected by the dealer. If someone has installed it by the manuals instructions, there will be a thru-hull fitting in the transom of the boat, 2" above the water line. If you have this connection, make sure it is connected. If it's not used, it is suppose to be coiled up and strapped in the engine compartment.

But with your problem occuring at high rpm, I'm leaning on the first mentioned problems, leaks of the cooling system or the bilge siphon system.

I hope you have enough information now to find and fix this problem. Let me know what you find out!............:cheers:

 

[Lars Gustafson]

Testing this weekend

Thanks again. I will test inspect this weekend and let you know. (I have the boat in a high and dry service.