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How cold of water is it okay to ride in?

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factory81

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Same doofus mechanic I have been taking it to said that the engines will run in cold water, but it is not recommended really.

Is there any truth to this?
 
Yes and no.....

I say yes and no because there are two different engines that we use in Seadoo today. The 4-TEC's are 4 strokes with a thermostat in the cooling system that regulate engine cooling. So they are un-affected by the water temperature in which they are riding.

The water temperature in places like Canada, Nova Scotia, and other northern territory have 2-stroke jet skis, I'm sure they ride in cold water temperatures, but I don't know if there is any negative impact on the engines.

The theory your mechanic is going on is engine temperature. In 4 stroke engines, the thermostat controls the flow of water through the engine. When these engines are cold, the fuel system is set up to run richer, because the block of the engine is cold. It needs more fuel for complete combustion till the engine heats up.
As the engine is heating up, the thermostat is closed. There is no water circulation in the engine until the temperature is above 160*F, then the thermostat will begin to open. They are normally fully open by the time they hit 180*F. Boil over occurs at about 220*F. Yes, many know that water changes to steam at 212*F, but the cooling system is under pressure (about 14 to 17 psi), therefore, will not flash to steam unless you vent the pressure of the radiator cap. When the engine gets to hot, builds to much pressure on the cooling system, the cap has a spring loaded relief valve in it, which then lifts, venting the overheating engines pressure. If you've got this far in the temperature range, you've likely blown a head gasket or worse.

So, to get back to the topic, the 2-strokes don't have this thermostat to regulate the flow of water. They use calibrated fittings at certain points to ensure you have sufficient water flow through the engine to keep it completly flooded with water. There is no boil over or freeze protection because your engine isn't closed and using anti-freeze. Therefore, the temperature of the water you ride in, will have an impact on the efficiency of the engine. Colder water will keep the engine colder. Depending on how cold, will cause you to loose fuel efficiency and engine performance. Although I don't know specifically about the engines design enough to make a statement on "thermal shock" (google it), it is possible to ride in water that is so cold, the engines heat created by combustion and the temperature of the water in the cooling water jacket, may cause a fracture some where these two temps collide. Normally at the "0" ring of the water in the head and the piston chamber.

Sorry for the long post, but this is a very technical question that may have big implications to "really cold" water riders.

For those members that ride in the North Atlantic, or in the North Pacific, ....or for that matter, anywhere in the cold water regions, tell us what you think about how your engines run on the colder temperatures.:cheers:
 
How cold are you talking? water here is WAY to cold to swim but i can still drive my boat if i wanted, BUT not safe unless you have the right gear like a floater suite witch will save your life if you ever had a problem. If you ride in cold water be safe and buy the right saftey gear.:cheers: and rigth now its duck hunting season so there lots of hunters that have 2 stroke outboards running around, and are 10hp 2stroker is still in the water. Oh and where you ride, Lake Michigan? im on lake erie so you should be fine to ride it a bit longer but you will need some sort of sort of floater suit
 
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This thread is funny because its only going to be 92 here tomorrow and I can't decide if it is warm enough to take the boat out. lol
 
I suggest if you ride in water colder than 32*...that you bring the ice skates.
You must be kidding about this subject...I used to ride on xmass eve(Dec 24) with - degrees and wind chill the same...but the water wasn't frozen yet. Got some great pictures for next years xmass chards... lots of pretty lights and snow everywhere.
I kept exposure of my standups to a minimum, and stored them inside a heated shop, back in upstate N.Y.
Karl
 
Yeah, there are boats that run in 10° weather. And, as they head to the north, to get snow crabs, they have to keep breaking ice off the deck, so the weight does not build up, and capsize them.

These motors have an open cooling sys, BUT also have a thermostat.

That means that the ocean water goes into a place in the exhaust, where it is heated to a certain temp, then it is dumped back into the ocean. From this source the cooling water for the motor is taken, (It is like a mini reservoir in the manifold) which is probably around 100°, but I don't know. I learned this by taking apart a boat motor a long time ago. Curiosity got me to looking. And, the motor was locked up with water in it. I got it running!

Anyway, Open cooling, with a thermostat is the answer.

Apparently, Sea doo does not employ this?

Nate
 
Yeah, there are boats that run in 10° weather. And, as they head to the north, to get snow crabs, they have to keep breaking ice off the deck, so the weight does not build up, and capsize them.

These motors have an open cooling sys, BUT also have a thermostat.

That means that the ocean water goes into a place in the exhaust, where it is heated to a certain temp, then it is dumped back into the ocean. From this source the cooling water for the motor is taken, (It is like a mini reservoir in the manifold) which is probably around 100°, but I don't know. I learned this by taking apart a boat motor a long time ago. Curiosity got me to looking. And, the motor was locked up with water in it. I got it running!

Anyway, Open cooling, with a thermostat is the answer.

Apparently, Sea doo does not employ this?

Nate


Your right about this Nate, but with the TLCS (total loss cooling system) that Rotax uses, there is no water pump. This boat your talking about, had to have a water pump to maintain pressure for a thermostat type system to work.
The water is preheated when it wraps around the tuned pipe before entering the block which is one reason I mentioned "thermal shock" at the heads because the water first enters the engine at the top of the head, where it's met with the heat of combustion and cold water before it moves to the tuned exhaust for pre-heating before entering the engine.

But this subject is not really a laughing matter, since a great many of our members are from Canada, Nova Scotia, Sweden, Norway, and other areas just south of the Artic Circle.

For those that live in these areas and are truly interested in the temperature affects to your 2 cycle engine (never mind Florida or any of these other Southern parts of the U.S.) while riding in such cold temperatures, "thermal shock" as defined by Wikipedia: Thermal shock is the name given to cracking as a result of rapid temperature change. Glass and ceramic objects are particularly vulnerable to this form of failure, due to their low toughness, low thermal conductivity, and high thermal expansion coefficients. However, they are used in many high temperature applications due to their high melting point.

Thermal shock occurs when a thermal gradient causes different parts of an object to expand by different amounts. This differential expansion can be understood in terms of stress or of strain, equivalently. At some point, this stress overcomes the strength of the material, causing a crack to form. If nothing stops this crack from propagating through the material, it will cause the object's structure to fail.


This is very important. I don't think you have to worry about riding in water that's in the 50s' but I think if your riding in water that's into the 40's, you may encounter this type stress on your engine. They are aluminum and won't damage easily by expansion and contraction but they can be damaged.

Being from the South part of the U.S. myself, I'm not speaking from experience, I'm speaking from the perspective of an engineer, who's taken courses in thermal dynamics.:cheers:
 
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Thanks Mr. Snipe.

I really doo think we then should be given a NUMBER that is the lowest temp of water that it can and should be ridden in.

And, that number should be a known number. Maybe even placarded on the machine.

I rode motorcycles for years (2 strokers!) in all kinds of weather, snow, ice, etc.

I never would have thought of stopping, for anything like cold!

Thanks for the warning.

I had been daydreaming of the possibility of using a HOOKA (like scuba, but with an air pump on the surface) system, and getting fish in alaska some day.

And, using a hot water wet suit.

I guess that is not such a good idea any more!

N
 
Good write up Snip, good knowledge as always. This might be a shot in the dark but maybe you could install an in line heater kinda thing to warm the incoming water up a bit. But like i was saying this time of year can be very dangerous to boat, Im at the cottage right now witch is on lake erie and the waves are about 4 meters high right now with 35knot winds. so if u do go out be safe.
 
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