How exactly does the cooling system work?

[Jfrenchws6]

So it's about to get very cold (for this time of year anyway) in the lower Susquehanna valley. Tomorrow I need to get some antifreeze in the engine before temps drop below freezing. I've been reading all the winterizing stuff and think I have it figured out. But after looking at the engine and identifying (I think) the correct hoses a question popped into my head. How the hell does this work?

If I have this correct, the large black hose on the port side of the ski comes up to a "Y" just before the exhaust pipe. After it splits, one hose connects to the bow side of the pipe while another smaller diameter hose connects to the pipe on the starboard side. It's this smaller diameter hose that I have identified as the water injection hose. There is also a clear plastic hose that connects to the bottom of the engine below the exhaust manifold and runs to the back. I believe this to be the "head drain" hose. On the starboard side there is the large black hose that connects higher on the head and has the T in it to connect the flush kit. Is this also a water intake hose for the head?

So assuming I have this right, how does the engine get water through the exhaust to cool it? Following the seadoo recommended procedure I should be pouring coolant into the inlet (port side) hose, but won't it just flow into the exhaust, down to the muffler and not reach the engine? I've been staring at diagrams and my ski for about an hour trying to figure out how this works and I'm lost. How can you cool an engine through the exhaust? I'm probably completely backwards with this but this is why we ask questions right? :facepalm:

 

[DavesNotHereMan]

I spent quite a bit of time going over the flow diagrams in the shop manual. I have an 01 GTX RFI, but I assume there is not much difference in the overall flow.

From the jet pump, the intake tube goes to a Tee. The small tube from the Tee goes to the Water Regulator which is mounted on top of the muffler. The larger hose goes directly to the intake on the head. There is another hose that goes to the large exhaust pipe and runs around an internal tube to cool the exhaust. At the high point of that circuit, is another small line that goes to the back "pee hole". Here is a photo of what the Tee looks like in my SeaDoo.

In that photo, I have removed the hose that goes to the head because that gets a funnel and the RV antifreeze.

Then I block the intake below the Tee and funnel more Antifreeze through the Water Regulator.

Hope it helps.



-Dave
Sent from my iPhone using Tapatalk

 

[Jfrenchws6]

I have a 95 GTS with a 587. Different engine but I assume the same principals apply. The hose with the T for the flush hose on the starboard side is the primary cooling for the engine. The intake hose on the port side is actually for cooling the exhaust pipes and muffler. I'm still confused as to why Seadoo says to pour coolant into the hose for the exhaust pipes and not on the other side. Should have taken some pictures before it got dark and used my awesome MS Paint skills to show how I think this works in my head so you guys can show me why my brain isn't working right :-D

 

[ocod]

Different engine but should be same principal
http://www.seadooforum.com/showthread.php?57271-1999-Speedster-Winterization

 

[Jfrenchws6]

Yup read that. Makes sense. Instead of disconnecting and tying the lines up you just clamp them off. Only difference is I don't have a second hose going to the engine like the one picture. It goes to a Y and then those 2 hoses connect directly to the exhaust pipe.

Really wish I could find a cutaway diagram of the engine or something like that just so I can understand how it flows through the engine and exhaust pipes.

 

[LouDoo]

Here's a diagram of the cooling system again different engine but very similar.

Lou

 

[ocod]

Yup read that. Makes sense. Instead of disconnecting and tying the lines up you just clamp them off. Only difference is I don't have a second hose going to the engine like the one picture. It goes to a Y and then those 2 hoses connect directly to the exhaust pipe.

Really wish I could find a cutaway diagram of the engine or something like that just so I can understand how it flows through the engine and exhaust pipes.

Post#5 has the 717 engine which is similar to the 657 or 587

http://www.seadooforum.com/showthread.php?45922-Water-coming-out-exaust

 

[Jfrenchws6]

OK I think I understand now. There are passages inside the exhaust pipe that cool the pipe and then exit out the pisser in the back. There is also a port that sends water directly into the exhaust gasses to do other stuff. Thats why you need to block clamp that hose because it will go right down the pipe and into the engine.

Also when you hook up a garden hose to the flush port your actually back flushing the system aren't you?

 

[CReynoldsMIZ]

OK I think I understand now. There are passages inside the exhaust pipe that cool the pipe and then exit out the pisser in the back. There is also a port that sends water directly into the exhaust gasses to do other stuff. Thats why you need to block clamp that hose because it will go right down the pipe and into the engine.

Also when you hook up a garden hose to the flush port your actually back flushing the system aren't you?

Correct and correct