650sx overheating/ steaming

[nailem]

Recently bought a 650sx. Ran it on the hose before I bought it and all seemed fine. Got it home and found a small crack in the water box, fixed that. I thought I had it all sorted out but now it starts to steam out of the pisser after about 15min. The cooling lines look right or like they should work.
Looking from the back of the ski the line on the right runs up to the top of the exhaust, out of the exhaust to a T, one side of the T goes to the stinger the other goes out a pisser.The left of the jet runs up to the bottom of the motor, it comes out of the top of the head and out a pisser (there are 2 pissers) the line coming from the top of the motor is the one that starts to steam. It does run water for the first 15min or so.

I read that it could be a bad head gasket even though my compression is 185 on both. I replaced the head gasket and I'm still steaming.

I tried running the cooling from the left to the bottom of the motor, out of the head to the exhaust, out of the exhaust to the T pisser and stinger. This just made it steam quicker.

Thoughts?

 

[TaintlessEd]

Take the cooling line off and hit it with an air compressor and make sure it's not clogged.


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[Vumad]

Sounds like you have a parallel cooling setup. Make sure your pump is actually set up for 2 cooling lines and they are hooked up correctly. Make sure you have water flowing out both cooling lines at the pump when you are flowing on the hose. If you do have parallel cooling, then you also have to have 2 hose flush fittings. If one line from the pump goes to the pipe and the other to the engine creating 2 seperate cooling loops (thus parallel cooling instead of dual cooling), but you only have one hose fitting for the flush, then something is strange. If you only have 1 line on the pump and 2 at the bulk head, then one of them at the bulk head is robbing the cooling system. Generally speaking, you should have 1 outlet for 1 inlet, assuming they are all of the same size.

 

[nailem]

I'll try blowing through the line. It looks near impossible to get the line off the bottom of the motor with out pulling the motor, is there a trick? Also looks tough to get to the lines on the pump, again is there a trick?

My steaming problem is not on the hose. You are correct that on the hose I can only run water to the motor. My over heating is while riding. I start put with what looks like good stream of water out both pisser but the motor side ends up blowing steam.

 

[Vumad]

I'll try blowing through the line. It looks near impossible to get the line off the bottom of the motor with out pulling the motor, is there a trick? Also looks tough to get to the lines on the pump, again is there a trick?

My steaming problem is not on the hose. You are correct that on the hose I can only run water to the motor. My over heating is while riding. I start put with what looks like good stream of water out both pisser but the motor side ends up blowing steam.

Before you start pulling off cooling lines, you can try to back flush the motor through the pissers. Water should be pushing out the water inlets in the pump. If you are not getting good flow out the pump while using the hose, then you have a blockage.

We have mud dobbers and they sometimes make nests in the holes on the jet ski. The pump is below the cover so on the occasional they will fill the cooling hole in the pump. The motor is fine on the hose because water is being pumped in. As soon as we put it in the water, it over heats because their is no flow.

You can still have another issue. If the waterbox was cracked then it probably over heated previously. Over heating can be caused by more issues than cooling system. You mentioned the head gasket where combustion chamber heat is mixing with cooling water. You can also have carb issues causing it to run lean. THis wouldn't be an issue on the hose because it's not under load, but lean in the water under load makes lots of heat. Exhaust restrictions can also create a lot of heat.

Ultimately you are probably going to have to take a few things apart to figure out the problem. Based on your discription, it sounds like you have wonky cooling and that should probably be corrected.

And as I mentioned before, you seemed to be describing parallel cooling but did not confirm that you have the pump tapped for 2 cooling lines.

 

[nailem]

It does appear I have a pump tapped for two cooling lines. I do get water out of the 2 lines.
No compressor near the water but I blew through the line and had air coming out and it didn't take much force to blow (insert joke). Attached are some pics of the plugs. Looks like one is lean to me, what do you think? Looks like I have some carb adjusting reading to do. I have no idea where to adjust.

 

[nailem]

Here is the cooling set up. I tried to plug off one line and run from the pump to the motor, then to the exhaust like I've read but it just made it steam quicker since the heat is coming from the motor by the time it got to the exhaust side it was already steam.

 

[nailem]

looks like I really need to go back through the cooling lines like you said. Where I'm confused is i have 3 lines off my pump. Looking from the back to the front of the ski i have 2 on the right. One is the siphon drain. The other one currently goes to the top of the header. It seems like there is good water flow to this one.
On the left of the pump it has a fitting on the pump, a hose comes off toward the back and does a U bend back into the ski. From here it goes to the bottom off the header then out to the top of the head and out. This is where my over heating is. I pulled the line off where it enters the engine compartment and ran the motor. Barely any water comes out from the pump but it does not seem to be clogged.
I don't get the two lines off the pump, one on the right has good flow, one on the left has poor flow.

 

[Vumad]

looks like I really need to go back through the cooling lines like you said. Where I'm confused is i have 3 lines off my pump. Looking from the back to the front of the ski i have 2 on the right. One is the siphon drain. The other one currently goes to the top of the header. It seems like there is good water flow to this one.
On the left of the pump it has a fitting on the pump, a hose comes off toward the back and does a U bend back into the ski. From here it goes to the bottom off the header then out to the top of the head and out. This is where my over heating is. I pulled the line off where it enters the engine compartment and ran the motor. Barely any water comes out from the pump but it does not seem to be clogged.
I don't get the two lines off the pump, one on the right has good flow, one on the left has poor flow.

The 2 lines on the right are the stock cooling and the stock siphon.

The line on the left is an added line for dual / parallel cooling.

The thing about that, is that the hull only has 2 through-hull fittings. The 3rd tube has a fitting on the inside but not the outside. That 3rd one with no fitting on the outside is an outlet for the stock exhaust. It was never intended to be a cooling line. I have seen where people turn it into a cooling line by pushing another tube into it, but that would be extremely restrictive. If this has been done on your ski, it could explain a few things.

For dual / parallel cooling, you want an electric bilge pump so you can remove the stock siphon. You should then run both cooling lines from the pump to the motor and cap that 3rd tube that doesn't have a fitting outside of the ski.

If you are wondering which fittings on your pump are which. The cooling lines are 90* into the pump. The siphon line points backwards and is connected to the reduction nozzle.

You ski shouldn't need dual cooling anyway. You can run a single cooling setup.

If you do run dual cooling, you can follow the B-pipe diagrams online if you have 2 fittings on your pump, your exhaust manifold and your head.

For parallel cooling, You still need 2 lines on the pump but only one on the manifold and the head.

 

[nailem]

I switch the supply to the motor to come from the right side of the pump. I'm getting a lot more water out the pisser now. After riding for 30min or so I'm blowing about 90% water but it still seems like there is small amount of steam. I rode for 45min this way and it seemed ok. If I get a thermal temp. Gauge what should the top of the head read after a good ride?

 

[Vumad]

I switch the supply to the motor to come from the right side of the pump. I'm getting a lot more water out the pisser now. After riding for 30min or so I'm blowing about 90% water but it still seems like there is small amount of steam. I rode for 45min this way and it seemed ok. If I get a thermal temp. Gauge what should the top of the head read after a good ride?

Mine reads around 140-160 iirc.

 

[nailem]

I'm about ready to take this thing out and sink it!
Still over heating, top of head is 205 after I ride for 15min. Probably a bit hotter because it took me a few minutes to get the hood off and get a temp.
I have good water flow when I start, shoots right out the pisser.
I put a new head gasket on.
Compression is 185 on both cylinders. Cold
What else would make it run hot? I would think maybe a tulipped valve buy then I wouldn't have good compression. Warped head? Still wouldn't think my compression would be so high.
I'm at a loss.

 

[nailem]

May have a break through. I just checked compression while it was hot and I have 180 rear cylinder and 100 on the front. Both were 180 cold. So what could this mean. Head?

 

[nailem]

Leak down held solid. Lost 0 psi in 16 hours.