Raw water cooling 2006 115 2 stroke optimax 1B310265

[Bunky2100]

Warning - I am new to the forum so take it easy on me
I have just bought and brought a wooden Albury 20 runabout from the Abacos. Brought her on her own bottom to FLA and engine ran like a top. I had Man of War mechanic service and check it out. Engine had approx 300 hours and Ive put on another 125. On my second outing since bringing her home I found she was not pumping water. Pee hole showed no signs and the alarm went off ect. I got her back home, ordered a new impeller and kit. Pulled lower unit and disassembled pump housing. Impeller looked okay but I replaced anyway along with new gaskets and faceplate. Reassembled, put on muffs and NO water. I checked pee hole and there was some debris in there. I cleaned it out and still no water. I pulled the thermostat and found it to be dry and no debris.
Im sure most of you guys and gals have seen this before, but this is my first Mercury. Any helo would be appreicaited.

 

[Chris1956]

The cooling system on that motor has a waterpump, a thermostats and a poppit valve. The thermostat controls the cooling up until about 2000 RPM. At that point the waterpressure forces the poppit valve to open. The poppit and thermostat are adjacent to each other. I would check them for function. Run a piece of weed eater line up the telltale and see if it is clogged.

Mercs use a short plastic tube (usually white) to assure the water tube is inserted into the waterpump. Hopefully you used it to make sure the watertube is in the waterpump, or you will not get any pumping action.

You did insert the drivekey for the impeller? Hopefully the waterpump base was not melted. If it was, replace it

 

[Bunky2100]

Thanks Chris. I inspected thermostat and poppet. I ran garden hose into poppet and it drained out water tube (lower unit removed of course). I removed the thermostat to see if that made a difference. Drive key is in place - but good thought.
I did get some debris from the telltale but worry there may be blockage further up the line.
TO make matters a little more challenging I cannot get the lower unit back on. I think that the shift rod is not matching up. I didnt touch the shifter, but did rotate the drive shaft slightly. Drive shaft is going back in. I have removed the lower unit three times and the two times iI replaced I had no trouble. Now im just 1/2" short.

 

[Chris1956]

See if you can backwash through thermostat housing, and see if you can get water out of the water tube.

To reinstall gearcase, make sure the gearcase is in neutral, and the control is also in neutral. Wiggle the throttle arm a bit to align the shift shaft splines.

 

[ajgraz]

Are you absolutely sure you got the waterpump back together right? I recall reading another thread where the guy somehow put the slinger (like a big, square cross-section o-ring, rides the drive shaft) inside the water pump housing (instead of on top)--still don't know how he got the water pump cover back on that way--and then for obvious reasons could not get that last 1/2" of insertion.

BTW, does your motor have a hose-threaded-end flushing tube ("coastal flush" I think Merc calls it) near the control cable entry area?

 

[Bunky2100]

Many thanks Chris and ajgraz. I have flushed down from the poppet and found water to run out of the tube that connects to the lower unit. So I think that way is clear. I'm thinking/worrying that there is some sort of obstruction further down the line. ?? Can't see a way to disconnect the telltale without disassembling the cowling around the engine.

I've put the cover piece outside the impeller housing as it was when I disassembled. I do no see a coastal flush fitting mg. That would help a lot!

I understood that motor should be shifted into foreword before removing lower unit. Two previous ri,es I removed with it in fore ward and no problem - now no go. The lower unit is in forward so I'm not too inclined to move shifter. Thoughts?

 

[Rodney Williams]

The engine doesn't have to be in forward. in fact I would ensure it's in neutral. Also, as Chris 1956 said, there is a white plastic tube that fits over the pump tube to align it with the water pump outlet. If you can't get the lower unit to go all the way up you'll have to rotate the drive shaft or get someone to turn the flywheel slightly to align the driveshaft splines with the crankshaft. Again, ensure that the impeller key is in correctly. I have a 2005 Opti and when using the muffs there is a long pause before water starts to flow out of the pee hole. I usually have to squeeze the muffs tight to seal the muffs against the lower unit until I get water to flow out of the pee hole. If the boat is in the water it start's peeing almost immediately.