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Discussion Starter #1
I prefer 2strokes because there lighter and much easier and cheaper to rebuild then the 4 strokes. I also love the smell!
I guess it comes from my racing days. I could pull the jug off the bike between heat races and redo the top end in a few minutes and be back on the track.
Grew up riding 2stroke dirt bikes(Yamaha YZ's 125/250) raced motor cross for yrs till I broke a knee in an accident. Decided it was time to quit and enjoy riding on the farm. Now I enjoy 2strokes on the water. I have 2 vxr pro's 93/94. And 2 GP800r's 01/02. Only Yamaha for me.

As for your other question about towing over 5 mph on the water. That issue has always been there. The manufacturers have just recently started putting it in the owners manual.(last 5 or 6 yrs maybe?) It's easy to resolve the issue with a valve in the cooling hose coming in from the pump. I have them on both my gpr's, but mainly for flushing after a day in saltwater as it allows better water flow to the motor.
 

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…..Grew up riding 2stroke dirt bikes...…….[B said:
"grew up"...hmmm...I tried that once for a few years....didn't work out for me - had to dress up and be nice. Phoey on that! I cant stand the noise and smell of two-strokes. Started out with a Honda 50 cub, had one of the first Honda 750's in the country (pre "K" series). Would "blow off" just about anything, including "vettes". Unfortunately, my wife started complaining that I was incurring too much "asphalt rash" so had to give up scooters....(last time was half a year in hospitals for re-constructive ortho. surgery...)[/B]

As for your other question about towing over 5 mph on the water. That issue has always been there. BULL FEATHERS - see my other posts...If you were right, my '93 See Doo GTX wouldn't have lived through hi speed towing all these years, including open ocean towing in rough water...

The manufacturers have just recently started putting it in the owners manual.(last 5 or 6 yrs maybe?) It's easy to resolve the issue with a valve in the cooling hose coming in from the pump. I have them on both my gpr's, but mainly for flushing after a day in saltwater as it allows better water flow to the motor. I agree with you there..
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NEVER try and cook a hippopotamus for lunch until you first clean the feathers off first.
 

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Towing recommendations HAVE always been in the manuals. I had a 92 Kawi 750SS that had the original owners manual with it and it was in there. Again, EVERY owners manual I have EVER look in had towing recommendations.
Here's a clip from a 97 seadoo owners manual.
 

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Discussion Starter #5 (Edited)
If you need the valve for your cooling line. Go to home Depots web site. Search rainbird valves 1/2" barbed. Cost is about $2.50. then get a couple clamps at local auto parts store.
 

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Towing recommendations HAVE always been in the manuals. I had a 92 Kawi 750SS that had the original owners manual with it and it was in there. Again, EVERY owners manual I have EVER look in had towing recommendations.
Here's a clip from a 97 seadoo owners manual.
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My '93 GTX's manual dosnt have that page. So what you are telling me is that the mfgs. knew even then that folks tow their skis behind bigger & faster boats.....Now tell me they aren't smart enough to engineer their water cooling systems so as not to destroy a motor....!
 

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And just how pray tel would you do this ?
I would imagine one reason they don't install a valve on the inlet is for liability issues. Do you realize how many people would forget to open the valve and fry the engine, then go after the manufactures for putting it there ? The other reason would be accessibility. It would have to be in a location that you can get to it. These things are crammed full enough as is.
The deal is they knew about it, they have informed us about it, and given recommendations on what not to do. If you insist on not following their recommendations, the consequences will be of your own doing.
 

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And just how pray tel would you do this ?
I would imagine one reason they don't install a valve on the inlet is for liability issues. Do you realize how many people would forget to open the valve and fry the engine, then go after the manufactures for putting it there ? The other reason would be accessibility. It would have to be in a location that you can get to it. These things are crammed full enough as is.
The deal is they knew about it, they have informed us about it, and given recommendations on what not to do. If you insist on not following their recommendations, the consequences will be of your own doing.
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agree with you to this extent - I forget ONCE to correctly position the shut-off valve I installed in line with my Wave Runner EX's cooling system, and good-bye motor!

All the more reason why the cooling system SHOULD have been designed to reflect how so many of us use our PWC's.

You telling me it is not possible to come up with a cooling system's plumbing as reliable as my old SeaDoo GTX? Horse feathers!

Is there some reason why all three mfgs. HAD to design their respective cooling systems to insure destruction from towing behind a larger boat - heck, even house-boats can go faster than the limits the jet ski mfgs. have put on. (again, in small print - I know..I know "when all else fails...read the instructions"....!

How come a lowly back-yard wrench turner like me can come up with a solution that requires NO action by the consumer? Dosnt say much for the pwc people...or does it suggest they are a bunch of deliberate crooks?

Simple solution - soon as I can find out where on my PWC's motor I can tap into its vacuum. For many many years, the automotive industry parts suppliers have produced reliable vacuum powered shut-off valves for our car's heating systems. Again, RELIABLE durable, off-the-shelf product..about thirty bucks. Install one of those. Engine starts....motor vacuum opens the cooling valve. Engine stops, vacuum fails, cooling water is shut off.

Which leads us back to the question...what are the mfgs. trying to pull off on consumers? We supposed to believe they have no clue how many of us use the product?
 

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The basic cooling system on pwc's has not changed. Water is forced in by pump pressure through a inlet at the pump, to the engine where it is (usually) preheated in the exhaust manifold, through the engine, out through the exhaust to cool it (so it doesn't melt the hull and rubber couplings, helps quiet the noise, and regulates the power curve) and maybe a tell tail on the side of the bow. When you tow it over the recommended speed it will pressurize the pump forcing water up into the exhaust manifold and start to fill the exhaust system. When it gets full, it will then start flowing through the exhaust into the engine. They have attempted to reduce this issue by designing the header pipe. It creates a high spot that makes it more difficult for water to flow through when towing, stopping, and the ski just sitting in the water. All I/O boat engines (except jet boat headers) use the u shaped pipe, and they actually have a flapper valve in the outlet to help restrict reverse water flow.

The cooling system on a car is filled and lubed with propylene or ethylene glycol, and the control valves aren't used much anymore. A lot of the systems now flow full time to aid in cooling, and eliminate the valve. Heat is controlled by a blend door that opens and closes as you adjust the temp setting. The system on a pwc takes in straight lake or salt water. Both will end up rusting the components of a heater control valve rendering it completely useless, hey but if you want to take the chance to trash your new ski, and have Yamaha laugh in your face because it was a modification you made that caused the failure, have at it. You won't know it has happened until its too late. Salt water will expedite this process.

A boat has a completely different engine and drive setup, so comparing the two is a futile effort.

The reason any warning is posted anywhere is there has at some point been someone that claimed a manufacture was responsible for a issue that was the fault of the owner of the product. So in essence, someone at one time probably flooded the engine of their ski and blamed the manufacture, so the manufactures deemed it ness. to put it in the owners manual.
As far as actual towing speeds, any boat should not be towed any faster than basic wake zone speeds. That part of the hull (especially the new thin material hulls like your EX) are not strong enough to stand the force the rope or strap puts on it at higher speeds, but it's your money.
 

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Discussion Starter #10
Not sure we're you've gleaned your info. The old vacuum diaphragm heater valves or vacuum controls period are not failure proof nor very high quality. I'm an industrial mechanic/machinest and co own an automotive radiator/heater and air conditioning repair. Vacuum controls have always been a money maker as there always leaking and or the diaphragm failed. Now days only a few even use them. Most have gone to micro/servo motors to open/close controls. Including all your guages in a vehicle are a servo moving the needle to where the computer says it should be. I'd be damned if I'd use a vacuum diaphragm for cooling control.
 

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Guess you guys are right - no way to make a common water shut- off valve reliable and anyway, I just imagined all those people towing their skis behind large fast boats at lakes Powell, Mead & others, all those harbors in So. Calif., shame on me for making this stuff up. After all, how could mfgs know how the consumer uses the product? So unfair of me. Of course I should know skis can’t hit water fast....hull might be water soluble....can’t thank you guys enough for straightening me out. Shame on all the major auto & truck mfgs. For using such unreliable junk in their vehicles.
 

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Oh, pardin me. You must be one of those rare people thatknow everything !!!
Ya know I really don't give a rats flying rear end what you do with your stuff, or how others tow their's. The info is in the manuals, like it or not.
I'm sorry you are so misserable that you deem it ness. to find fault with everything and everyone.
Enjoy your new ride.
 

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rodsatheart;7093693 Ya know I really don't give a rats flying rear end what you do with your stuff said:
. . . . .

Hi again Rod!

As you saw in a now censored "thread", I thank you for your help in running this forum. As I noted, this forum even in the short time I have been here, has already proven to be of value to me.

I do accept your statement you are just here to help, and thank you again for that; yes, I believe you that you are not an "industry plant".

Fact remains you do seem to vigorously support what the industry has and has not done on the cooling system issue to protect consumers of their product.

So you don't "give a rats flying rear end" how others tow their skis? I disagree with you to this extent, the industry should.

If you seriously do not know that it is the custom on lakes Powell & Mead for people to tow jet skis behind their boats at normal cruising speeds (while en-route to camp-sites, going up-river, etc) , tell me how to "attach" video and/or "stills". We are taking our new Wave Runner up to Powell at the end of next week; will be pleased to set you straight on this.

From videos I have seen elsewhere, lakes Powell and Mead are not the only places where jet ski owners tow their skis behind boats.

I do not accept the proposition that it is impossible to make a cooling system that will not destroy a ski motor. I do not believe it is rocket science.

I do agree with Dave to this extent...no question about it - there is some pretty crappy hardware out there on the market. "Cost cutters" can really screw things up for the consumer.
 

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I do not need to be set straight on anything !!!!!!!

The fact is the there are warnings in the owners manuals in plain print, in plain sight. If someone wishes to go against those warnings and instructions, the outcome is their problem. Just because others are doing it, doesn't make it right. If all those same people were jumping off a cliff, your are you going to follow them ? Prob not.
I never said it was impossible. The cooling system does not destroy the engine, the process of blatantly doing exactly what the manufactures have warned against, without taking the necessary precautions is what ruins the engines. The problem is that you just won't, or or not willing to accept this.

This topic is done.
 
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