engine tubing in 2003 launch ss

[02LaunchSS]

I recently installed a new impeller on my 02 launch ss (direct drive). After this replacement, we flushed the boat in the driveway as is normally done using the in line flush kit. During the flush, a piece of ~3 inch rubber engine tubing burst/split spewing water everywhere. Does Skiers Choice have replacement tubing of this odd contour available, or should I just get some replacement tubing from the autoparts store and curve this to fit? Also, I guess the timing of this incident could have been coincidental...but it makes me suspicious that something went wrong during the impeller replacement (though this was a very straightforward task). The tubing in question is the very frontmost piece on the right (driver's side). Any ideas or help is greatly appreciated!

[DKJBama92Mariah]

That 3" tubing would be your exhaust hose. DO NOT use auto hose; twould be a good way to sink you boat. You can order replacement hose from discount inboard marine at www.skidim.com

Did you replace the impeller because of an overheat or just part of routine maintenance. If you overheated, it wouldnt be a bad idea to replace the exhaust hose on the other side. The hot exhaust gases without cooling water will quickly kill the structural integrity of the hose.

Holla back with more info if you have any questions.

DKJ

[02LaunchSS]

Thanks for the quick reply! No, there was no overheating, and yes this was just a routine maintenance replacement of the impeller...though it was the first time (in 4.5 years) we had replaced this. It was just strange to have this happen...we flush the boat after every single trip out to the river, and this was the first time ever to have a hose bust like this.

[DKJBama92Mariah]

Oh well, you cant really question it. Doodoo happens. Just be glad it happened when you were flushing instead of on the water.

[IndyMatt]

Hey guys just curious... not sure if you guys are talking about the same hose or not. If its on the front side of the motor it is the coolant (raw water) line from the impellar to the thermostat housing (slightly smaller than 3" though) The exhaust hoses are 4" and run from the aft end of the manifold risers straight back to the through hull fittings, not making any bends. In regards to the water pump lines, its not unheard of after several seasons to lose some flexability... being an 03 it may have been an exsisting flaw in the line that just now gave way. Any heavy duty automotive type radiator hose rated to at least 200 degrees will work fine in your coolant system, espically with your coolant being cool lake water. If your having trouble finding the hose with the right bends you can always use straight hose, galvanized elbows & hose clamps. Good luck!

[DKJBama92Mariah]

Using auto grade rad hose would be a bad idea. Marine water hose has a strong steel coil core to prevent hose collapse from the suction of the raw water pump and bursting due to heat. I have been scolded for using auto parts and i have done the same to others. Its just not worth it. Use of non-marine parts and components endangers your family and your boat. If an insurance claim arises from the failure of the auto part( i.e., the hose bursts and severely floods or sinks the boat), your insurance company can and will deny the claim if they find out.

[IndyMatt]

I think if you would cut into one of the cooling lines you would see that there are no metal coils inside. Your absolutely right in regards to the use of automotive components (components being the key word) that are not manufactured to withstand the marine environment, especially components that are cooled with raw water instead of an antifreeze mixture. By all means, check with your dealer or take your burst hose to a repair shop to purchase a similar guage and temperature rating. You can also cut into that hose to look for those coils. Remember, the cooling system is pumping cool water to your thermostat to cool the motor. The only lines in the cooling system with coils are the two 4" hoses that run from the manifold to the thru hull exhaust. These coils prevent hose collapse that could cause an accumulation of exhaust fumes in the motor box. The raw water line from the through hull to the water pump may also have some coil, here again to prevent collapse from the suction of the pump. The lines secondary the pump are presurized (thus your burst) and coils would provide no purpose. Here again, this is a moderate pressure, low temp application; so examine the hose you have and replace accordingly.

[02LaunchSS]

Ok, so I bought the replacement hose from discount inboard marine. It was a coolant system hose with a 1.75 inch inner diameter ("HOSE FORMED WP/THERM HSG" was the description from d.i.m.). It did have some inner coiling which presumably helps prevent kinking of the line. Anyhow, the problem now at hand is that there appears to be some blockage in the cooling system; we pulled the boat out to flush it again, after about 10 sec of running the engine, the same piece of tubing started to swell though did not burst because we shut the engine off as soon as we observed this. Additionally, the tubing that leads from the impeller to the "y-junction looking piece" on the front top center of the engine started leaking water where this tubing comes in to this junction. Both of these observations led us to believe there is some obstruction in the coolling system lines (again I am suspicious of some rubber from the old impeller having melted to the innards here??). So I suppose my question now is: how can I get information on the plumbing of the coolant system (we do not know how to try to find this obstruction because we know nothing of the water flow through the engine). Any and all help in diagnosing this is much appreciated and thanks for the help thusfar!

[DKJBama92Mariah]

Is there any way you could post a pic of the hoses in question. I'm having a hard time visualizing which hose you're talking about. Also, is this an Indmar or PCM engine?

[IndyMatt]

Sounds like you have somthing obstructing the flow in the thermostat housing. Remove the hoses and unbolt the rectangular box from the top; it comes apart in two pieces (might be painted together) you can open this and inspect the interior, see where the clog is. If this is clear check the cooling hose secondary the box for obstruction, when you first start the motor your thermostat will not be open and the bypass may be restricted. Just curious, when you removed your old impellar, were any pieces missing? Do you have a raw water strainer on your pickup?