Cooling system blockage

[Tman240]

Okay, its my question day since I'm winterizing two 96 XP's...both with their issues. This one...

I noticed no cooling water discharging from the exhaust pipe...which should have a steady stream I believe that is coming from the box and the bottom of the engine. Cooling water is discharging from the CSI and in the pump assy at the pressure zone as expected.

The clear tubing appears obstruction free...at least what I can see of it. Any suggestions on how to eliminate a blockage somewhere...is it likely a blockage?

Tom

[1fastski.com]

Re: Cooling system blockage

if your running it on a hose and not blocking the in hose then you wont get the pressure to go everywhere .

[Tman240]

Re: Cooling system blockage

Are you saying I should clamp or partially clamp the engine inlet cooling line? My other ski, also a 96 XP, doesn't exhibit this which is what got me started on thinking there was a blockage somewhere in that clear tubing that drains from the bottom of the engine.

I have the engine outlet hose clamped of course to prevent that quick exit of water out the back.

It just seems real strange that not a drop of water comes out the exhaust on this ski when running on the hose.

Thanks for any input.
Tom

[radiocontrolhead]

Re: Cooling system blockage

it was hard for me to understand what you were saying. because you switched from one ski to the next quickly.

here is how u properly run your skis off a hose. you will need a clamp, and clamp down the cooling inlet hose, you close it off before the hose fitting. then you turn the engine on, turn the hose on, do what u need to do, then water off/engine off. done.

from what i read, you clamped the coolant outlet /exit hose? thats why you're not getting any water from the exhaust, you're overheating your engine becaue water ins't cycling through.

[Tman240]

Re: Cooling system blockage

I was just trying to compare what I see exiting the exhaust between the two jet skiis.

Attached in this post is the cooling system picture and where I have clamped the line. I'm sure we are saying the same thing but perhaps confusing since when running on the hose, the cooling system is in reverse for the most part compared to it running on the water.

Bottom line is I am certain I have it clamped correctly and concerned that nothing is coming out the exhaust pipe. The CSI is 'pissing' and there is flow out the jet pump but nothing out the exhaust.

[radiocontrolhead]

Re: Cooling system blockage

whats weird is that hose inlet wehre the clamp is.... is supposed to be showing arrows toward the engine, not the exit.

[Chris]

Re: Cooling system blockage

Radio,
That drawing IS correct. That fitting is one of the water outlets. The hose fitting is in the exit line. So when you clamp the outlet off, the water hose back flushes the cooling system. The normal water inlet comes from the pump to the other fitting on the back of the head.

Chris

[radiocontrolhead]

Re: Cooling system blockage

so u mean to tell me that the water comes from the pump pushing it through the hose lines? but when towing a ski, which hose must you pinch to prevent it from flooding the engine? and just by towing it fast enough will rush water through the whole system?

[Chris]

Re: Cooling system blockage

I believe you pinch the one coming from the pump when towing. You pinch the outlet hose to flush-keeping the water from just running out and not going through the engine.

[Tman240]

Re: Cooling system blockage

Radio,

Your understanding is correct. Under normal running conditions, cooling water comes from the jet pump by the nature of what occurs within the jet pump area/venturi. When towing, you can induce the same effect causing water to flow into the cooling system.

I've never towed a ski but my logic tells me you'd have to clamp off the water inlet hose before the Tee fitting...or just stay below the recommended speed limit when towing.

Tom

[Bill O'Neal2]

Re: Cooling system blockage

Yes. The jetpump produces water pressure ( which is necessary to push water through the system).
When towing, you want the clamp on that water inlet line, the one from the pump to the engine, as the water pressure will still be produced by the venturi nozzel and forced into the engine as it is towed through the water.

Water enters the scoop grate, goes through the vane section of the pump and enters the venturi nozzel where the water pressure is increased because of the smaller exit side diameter of the back of the venturi nozzel. This highly pressurized water is forced through the motor via the hose from the pump to the engine.

The water enters and exits the pump and ventrui nozzel wether or not the motor is running when the boat travels through the water, like when being towed behind another boat.

[Tman240]

Re: Cooling system blockage

Bill,

When on the hose, shouldn't there be cooling water coming out the exhaust by two means ;

1.) Water coming from the muffler (water box)
2.) Water draining from the bottom of the engine through the clear tubing which terminates right at the exhuast outlet?

Getting back to my original question, I don't see a drop of water coming from the exhaust at all on this ski. My other ski, plenty of water discharging from the exhaust when running off the hose.

Tom

[radiocontrolhead]

Re: Cooling system blockage

if water isnt' comming out of the exhaust, coudlnt' that mean that there is a blockage in either the engine drain line or the exhaust regulator?

[Bill O'Neal2]

Re: Cooling system blockage

Clyinder drain lines are often packed with sand and completely blocked.

In order for water to exit from the exhaust pipe if you blocked or pinched off the clyinder drain hose, the water would need to run for awhile to fill the pipe and the muffler, then climb over the the big U in the exhaust hose between the muffler and the thru hull exhaust fitting.

[Tman240]

Re: Cooling system blockage

Okay. At the beginning of the season there was a plug of sand in the hose which I cleared...but perhaps there is still some sand further up the line at the cylinder exit.

Never touched that area yet so not sure on access but will have a look tonight to see if I can't get in there and dislodge any blockage. I assume this would be high priority to get done and is impeding engine cooling?

Thanks Bill.
Tom