# cooling system clogged on my jet drive outboard?



## RedfireSVT (Mar 7, 2013)

i went through some mud and sand and now my cooling system appears to be clogged. the water was barely coming out the spout so i changed the water pump impeller and that seemed to help a little but it still isn't flowing anywhere near what it should. i see there is a fitting down on the lower unit housing where i can screw in an adapter for a water hose to flush it out and i'm wondering if anyone has done this? i have a feeling there is sand and mud in my cooling passages so will flushing it get this stuff out or should i take it in for service? what type of pressure should i use when i turn on the hose? i've never had to flush one of these out before but something is clogging the cooling system so i need to get it working properly before i can use my boat. any advice would be appreciated. the boat is a mercury 90/65hp 2 stroke jet drive.


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## S&amp;MFISH (Mar 8, 2013)

I've had that problem on my 115/80. Simple fix. Take the hose and fitting off the head. Use air pressure to clear the obstruction out of the hose. While you have it off,start the engine while flushing,you should have a healthy stream flowing. If not,your head may be clogged so bad that it has to be removed. I've had this happen twice. The first time I took it back to the dealer,after running it for a couple of months with that condition. they fixed it and told me what to do in the future. So I do it myself whenever needed.


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## RedfireSVT (Mar 8, 2013)

thanks for the reply, that helps alot! :beer:


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## Paul Marx (Mar 8, 2013)

I fish saltwater and had a jet . I bought the fitting that conected to the inlet you are reffering to just to keep it clean inside. Your pisser may just be clogged . Run a small wire up into it and see if that helps. I highly recommend a water pressure gauge mounted to the console . they are cheap and easy to install. That way if the pisser clogs you can still see if you are getting good water pressure to the head.


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## RedfireSVT (Mar 8, 2013)

thanks! when i run the hose through that lower fitting to flush out the cooling system do i need to worry about the water pressure in the hose? meaning can i just turn my hose on all the way do do i need to keep the water pressure lower? i would think since i am trying to flush it that the more pressure the better but i didn't know if that could have any negative effects.


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## PSG-1 (Mar 8, 2013)

I fish saltwater and often use my boat to dredge my channel, so, it tends to get clogged. I carry a little primer bulb with a short section of hose. Since I removed the pisser fitting, and have the cooling hose sticking out the cowling, I can stick the barb fitting on the end of the primer bulb into the hose and back-flush water into it, until the obstruction is cleared. I also have a water PSI gage at the console.


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## Paul Marx (Mar 8, 2013)

When I bought mine I bought the flush fitting . It's just a 3/8s to a water hose fitting . I always turn the water on all the way and never hurt anything. When I hung the motor on the boat I told my mechanic I want a tempgauge and a pressure gauge . He told me I didn't need a temp gaugebecause water cools it and if I didn't have pressure I would over heat .


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## RedfireSVT (Mar 8, 2013)

thanks for the replies. i removed the pisser hose from the fitting on the engine and stuck an air hose in the end where it comes out of the cowling and sure enough a small pebble and some other junk came shooting out when i shot air in there. i don't know how that pebble made it all the way to the spout but it did. hooked it back up and it's working great! so thanks everyone!


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## susqyg3 (Mar 8, 2013)

A lot of guys keep some line from a string trimmer in the boat to knock stuff loose.. My yamaha has a nipple fitting where the hose comes out of the cowling and it causes silt to back up there.. Definitely can be a pain


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