Bogging Issue and Really Hot Waterbox

[HiImScott]

Only a few weeks til the Dells Freeride, and I would really appreciate some help with this one...

I have a 701 RN Superjet with a B Pipe, stock waterbox, and dual cooling with a FCV. The cooling is routed pretty much identical to the picture below; with the only difference being that I used a Y fitting to connect the engine outlets back into one pisser. The pisser from the engine is 6.5mm and the exhaust pisser is 8mm.

I ran it all last year like this with little to no issue. This year I took it out and it seemed to run great for 15 minutes or so, but then all the sudden it bogged really bad and it wouldn't pull out of. I ran it to shore (not that far, but bogging the entire way) popped the hood off and could hear what sounded like the crackling noise of something being really hot. Splashed water on the expansion chamber and it didn't even sizzle, but then I realized it was the waterbox which had gotten hot enough to melt some hydroturf and a little bit of my steering cable. Water beyond sizzled off that thing, it was HOT! I know water was coming out both pissers while I was riding so I have to imagine the stinger was getting water. Any ideas to what the problem could be?

*Full disclosure: I did make the following mods to the ski over the winter:

• Blasted and ceramic coated all of the exhaust components
• Replaced the two lower screws on my B Pipe with oversized screws. I don't know what they were set at before because they were siezed, but they are both closed now and the top screw is opened enough to spray a decent mist when hooked to a garden hose.
• I found that the timing was approximately 1-2 degrees retarded before, so this year I adjusted it to be 1-2 degrees advanced.
• Replaced a bunch of old wiring with new stuff. I fought poor connections all last year.

 

[Roseand]

Is this your first time using a flow control valve? It sounds like it's not opening when you need it to. This happened to me when I ran a restrictor before the FCV and couldn't build up enough pressure to open it. Waterbox got extremely hot, melted the cooling line on the stinger and I had an exhaust leak that made it run like crap. If you've got the ski on a trailer or in a stable place in the water, pop that cooling line that's on the stinger off and vary the throttle to see when that FCV is opening. That FCV is the only place your waterbox is getting water through...

Actually, looking at that diagram, it looks like you might need to restrict the pisser right before the FCV to build up some pressure for the water to open up the FCV.
Sounds to me like your FCV isn't opening when it should due to not enough pressure.
my .02, same thing happened to me.

 

[HiImScott]

It isn't my first time with the FCV; I have ran it since I bought the ski 3 years ago. You did give me an idea though... maybe its not that my pissers or FCV changed, but its that my head pipe adjustment screws did. If the lower or mid screw was dumping a bunch of water before (not sure if it was or wasn't) it may have been enough to cool the waterbox even without the FCV opening when it should. Now that they are for sure closed it may not be getting enough water. I read through that massive cooling thread and I found a recommendation of a 4mm pisser so that makes me think that the 8mm one I am running is likely too big, and you may be right.

 

[Byeai]

It's cause on the line that has the fcv u have a pisser so all ur pressure isn't going to the fcv it's going over board so it can't open the fcv to get water into the box

 

[Roseand]

The adjustment screws don't put out near enough water to cool a waterbox. They only let out a pressurized spray to change the exhaust waves. They're not designed to cool the box, only the chamber. Zack from PHP told me this. So yeah, that's probably your issue. Pull it off the stinger and hold it over board and see when and if it opens. You can just use a hose clamp on that pissed line to build pressure too,and adjust as needed.

 

[Roseand]

It's cause on the line that has the fcv u have a pisser so all ur pressure isn't going to the fcv it's going over board so it can't open the fcv to get water into the box

Yep exactly

 

[HiImScott]

The adjustment screws don't put out near enough water to cool a waterbox. They only let out a pressurized spray to change the exhaust waves. They're not designed to cool the box, only the chamber. Zack from PHP told me this. So yeah, that's probably your issue. Pull it off the stinger and hold it over board and see when and if it opens. You can just use a hose clamp on that pissed line to build pressure too,and adjust as needed.

Not to say you or Zack are wrong necessarily but with those screws backed out a ways and the chamber hooked to a garden hose I was very surprised by how much water would flow through those holes. If that didn't keep it cool idk what did because I didn't change anything else in my cooling from last year, and I never had the issue before.

It's cause on the line that has the fcv u have a pisser so all ur pressure isn't going to the fcv it's going over board so it can't open the fcv to get water into the box

Are you suggesting no pisser at all, or just more restriction on the pisser that is there? No pisser at all would basically stop flow on the head chamber at idle... The only flow would be through the adjustment screws.

 

[Roseand]

Not to say you or Zack are wrong necessarily but with those screws backed out a ways and the chamber hooked to a garden hose I was very surprised by how much water would flow through those holes. If that didn't keep it cool idk what did because I didn't change anything else in my cooling from last year, and I never had the issue before.



Are you suggesting no pisser at all, or just more restriction on the pisser that is there? No pisser at all would basically stop flow on the head chamber at idle... The only flow would be through the adjustment screws.

Hmm. It's definitely not the main source of water though, and your screws most likely shouldn't be open much if you get a lot of flow to the midpipe. You want a high speed spray , not a thick flow.
Your setup is a little different than most. Usually you'd run two to the exhaust mani, one out of the head to a pisser, then one to the midpipe, then from the midpipe to a pisser with a tee, and the fcv after the tee.

 

[Byeai]

Not to say you or Zack are wrong necessarily but with those screws backed out a ways and the chamber hooked to a garden hose I was very surprised by how much water would flow through those holes. If that didn't keep it cool idk what did because I didn't change anything else in my cooling from last year, and I never had the issue before.



Are you suggesting no pisser at all, or just more restriction on the pisser that is there? No pisser at all would basically stop flow on the head chamber at idle... The only flow would be through the adjustment screws.

I ran no pisser on that line when I I had my 718 never had a issue might have to open or close the fcv but u can do that when ur box is cooler and you know what ur temp is

 

[HiImScott]

Hmm. It's definitely not the main source of water though, and your screws most likely shouldn't be open much if you get a lot of flow to the midpipe. You want a high speed spray , not a thick flow.
Your setup is a little different than most. Usually you'd run two to the exhaust mani, one out of the head to a pisser, then one to the midpipe, then from the midpipe to a pisser with a tee, and the fcv after the tee.

Yeah I have a high speed spray now. I will check when the FCV opens and go from there.

I read through that long cooling thread and saw that many people route the way you are talking about, but most agreed that both ways will work well. I opted for the parallel cooling routing so I can fine tune engine and exhaust temps independent of each other. I also figured it would ensure even cylinder cooling, and it would make it easier to track down any points in the system where a line may become plugged. Just my thought though, it could be flawed.

 

[Byeai]

Run it how u have it just take out the pisser before the fcv

 

[Roseand]

Yes running it parallel will make it easier to tune it. However, if your engine line gets clogged you're screwed and could melt down your motor. With my setup the worst case scenario is I melt some cooling lines, have an exhaust leak, and my ski runs like crap.

 

[yamijumpn]

Im running parallel setup as well and have considered the risk of the engine line becoming clogged. I normally keep an eye on the pissers and if one looks weak its probably a sign of being clogged. If it would stop pissing all together then you know you have a problem....

From my readings/experience test the screw openings on a hose a low flow and the outlet of the header plugged. You will see that beyond about 1/2 turn out the spray gets thick rather than the misting spray desired.

 

[Quinc]

Should look like the below. You are losing all your pressure out that 3rd line going out the pisser on your head and do not have enough pressure to open the fcv. Edit: You should check the temps on the chamber and cylinder/head as well. You do not want to run them too cool. I

 

[BruceSki]

Your pissers are not your problem. Our whole crew runs their cooling like your first picture with no issues.

Take your waterbox out of the ski and shake it around.

My guess is you have a broken baffle in yours. It's blocking the exit partially and bogging and heating up from lack of exhaust flow.




EDIT: with that cooling setup there is so much pressure in the headpipe you only need about 1/16th turn on one b pipe screw and you'll have plenty of pressure to open the flow control even with a large diameter pisser.

 

[Roseand]

Your pissers are not your problem. Our whole crew runs their cooling like your first picture with no issues.

Take your waterbox out of the ski and shake it around.

My guess is you have a broken baffle in yours. It's blocking the exit partially and bogging and heating up from lack of exhaust flow.

How can you be sure? With a larger pisser before that flow control valve, there's a very very good chance it's not opening. Same exact thing happened with my ski. But if that doesn't work, check the waterbox. Stranger things have happened!

 

[BruceSki]

I'm sure because I run the exact setup he has there and drilled my oem pissers larger than stock to keep the pipe cooler.

All it takes to prove out the flow control is a quick check with the ski strapped to the trailer or nosed up against the dock to make sure it's opening at the RPM you desire. I don't mess around with pop off pressure testing and bench testing. Complete waste of time.

Field testing under a load is the only way to do it correctly in my opinion.

 

[BruceSki]

I'll just leave this here.

 

[HiImScott]

Your pissers are not your problem. Our whole crew runs their cooling like your first picture with no issues.

Take your waterbox out of the ski and shake it around.

My guess is you have a broken baffle in yours. It's blocking the exit partially and bogging and heating up from lack of exhaust flow.




EDIT: with that cooling setup there is so much pressure in the headpipe you only need about 1/16th turn on one b pipe screw and you'll have plenty of pressure to open the flow control even with a large diameter pisser.

I took the waterbox out already and it doesn't sound like there are any loose pieces shaking around in it. I need to get it back together and start doing some testing.