Backflushing water danger?

[Technohedge]

Just curiosity but how do you get water in the engine by flushing the ski on a hose and not starting the engine first (not that i plan on doing this)

Trying to fathom out the cooling diagram (specifically XPL 951) and the only way i can see water getting in the exhaust near the manifold is from the water injection from the regulator?

 

[Coastiejoe]

When the engine is running, there is pressure in the exhaust manifold and therefore everything is pushed out the exhaust. If the engine is not running, there is no exhaust pressure, the water fills the exhaust manifold and then runs into the engine through the valves.

 

[Technohedge]

Exactly which route/tubing does it enter the exhaust manifold on the 951? as far as I can see the water jacket around the exhaust tube is sealed off rom entering the actual exhaust port itself, the only route for water to get into that area is via the water injection hose?

What valves do you speak of?

thanks

 

[Coastiejoe]

Exactly which route/tubing does it enter the exhaust manifold on the 951? as far as I can see the water jacket around the exhaust tube is sealed off rom entering the actual exhaust port itself, the only route for water to get into that area is via the water injection hose?

What valves do you speak of?

thanks

Valves in general.
4-tecs have valves. 2-strokes have a different system but same principle when it comes to the water passing in reverse through the exhaust manifold.

 

[Technohedge]

Specifically the XPL 951, 2 stroke, as far as Im aware the only valves it has on the exhaust are the RAVES which don't close the exhaust port fully?

Anyway im more interested ion exactly what mechanism allows water into the exhaust port so I can understand the cooling system better

cheers

 

[Kris69]

The RAVE valves don't close the exhaust ports at all on 2 strokes. What they do is change the port "height" moving the power curve up and also providing bottom end torque at idle etc.
When you connect a hose to the flushing point, water will flow through all the hoses and one hose goes into the exhaust manifold (does in my GTI LE RFI'S) and what happens is the manifold will fill up quicker than it can drain out, eventually filling up past where the hose is attached then it will spill into the cylinders/crank case.
With mine, if it needs to be towed over a certain speed then the inlet hose needs to be clamped off or it can do the same thing.
The manifold needs exhaust pressure to push the water out.

 

[Technohedge]

Thanks Kris69 thats what i was looking for. from what i understand there is one water line from the regulator (fed from the engine block) that sprays into the interior of the exhaust. It was just confusing looking at the diagram as there are three other lines that go to the exhaust in the cooling system, but these apparently feed the water jacket around the exhaust and do not enter the exhaust interior itself.

cheers