1993 Yamaha 15MSHR

[Rsplatt]

I have this 1993 Yamaha 15hp. It runs wells but I have a clog in the water coolant line. The last owner let it sit for a while after running it in heavy salt water. I’m trying to clean the line and am having difficulty. I’m wondering if I can bypass the clog, or if the area that is clogged is vital to cooling the engine. To me, it looks like the area that is clogged is right before the water is sent out of the pisser valve. Though I am not familiar with this engine and I do not know where the water would normally be expelled from. I’ve attached pictures, the clogged is circled in red.

Any advise on how to clear the line?

Is the clogged area vital? Can I bypass it?

 

[maintenanceguy]

If I understand your pictures:

It looks like there is water flowing out of the hose from the motor and only the fitting through the cowling is plugged? If so, I would first try pushing a wire through that fitting. If that didn't work, I would drill it out. I'm sure you can also order a new fitting.

 

[nccatfisher]

I would just about bet that clog when you get it out is caused by a dirt dobber. Get after it with a stiff piece of wire or take a small drill bit and just twist it in your fingers. If you start removing dirt particles you will know what you are dealing with and proceed accordingly. You may take a small flat screwdriver and can use it as a hand drill and work the clog out. I am not familiar with that motor so I don't know if that fitting goes straight through or is a 90 degree angle. You may have to work it one way then work at it from the other then have to get after it with an air hose. But in the end I am betting on what caused it.

 

[Rsplatt]

Thank you, I’ve been working at it on and off over the past week. Been using a small drill bit. The small amount of martial I’ve been able to remove has been a white almost concrete like substance. Maybe a mixture of crushed shells, sand, salt, and mud. I haven’t been able to make much progress and penetrating oils haven’t helped either.

Sadly I’m not familiar with this engine to know where the exterior/other end of the clogged area is located. If I knew, I’d at least be able to work the clog from both sides.

 

[nccatfisher]

Yep, dirt dobber.

 

[samuelh1987]

Just went through the similar issue on a 86 Yamaha 6hp. I ended up removing the cylinder head and flushing the passages with a water hose followed up by a air compressor. Your issue would have to be in the outlet nipple. I'd think a solid bit of wire would clear it right out.

 

[turbotodd]

Most of the duck hunters around here are VERY familiar with the restrictor fitting in the bottom cowling. They get plugged up with dirt sand whatever and when you pull the hose off it flows fine, put the hose back on the restrictor, very little comes out. Most of us carry a piece of wire so that when it does get plugged, just run a wire up inside it's "pisser" and it usually busts the stuff loose and flows fine from there out. Once in a while it won't and then pull the hose off and blow backwards from the outside of the cowling in, whatever's in there usually comes right out.

If there's anything in the engine, is is usually in the thermostat area. Normally it's a piece of a failed impeller but it can be anything really. I don't do many 15's anymore but on most of the 25 (2 stroke), the thermostat is right on top of the cylinder head, 2 10mm bolts holding it on.

 

[Rsplatt]

I appreciate the advise, thank you. Been working at it with wire and drill bits. It’s like drilling concrete.... I think it’s been plugged for a long time.

 

[turbotodd]

yeah there have been times when I couldn't get the stuff out. Sand, rocks....you can't really drill them. In some of those cases I've had to remove the hose from the block and push it out manually.