johnson 15 horse water exit?

[oldboat1]

I'll guess that on muffs you pressurize the leg when it is full of exhaust water. You might back off the hose pressure and see if the stream slows or stops.

It would be good to let it idle in a barrel and monitor head temps. While the motor may be slow to heat up, once you get it up there keep an eye on it. The main danger running in a barrel is overheating -- exhaust will heat up water in the barrel. It can go from safe temps to overheating pretty quickly -- can minimize danger by running slow and keeping a hose running to top off water. Sink the leg deep (about half way up).

I wouldn't be too quick to pull out the t.stat, as it's a little tricky on the '85 -- try to determine if temp is properly regulated first.

Good luck with it.

 

[jdhgcb]

I was wondering about a PO removing the t stat because it was not getting warm at all plus a little rough at idle to suggest not getting up to temp. I am used to a much bigger motor and when you hook the hose up you get water out the prop and other relief areas in a hurry and with some noticeable flow. may just be expecting too much from this little guy. I plan to get a no contact thermometer and run in a tank in the next couple days to get a more accurate idea of what is happening. If it doesn't warm up or gets too hot then I will know better where to go next. thanks everyone for all the help its greatly appreciated. will post results soon

 

[flyingscott]

I was wondering about a PO removing the t stat because it was not getting warm at all plus a little rough at idle to suggest not getting up to temp. I am used to a much bigger motor and when you hook the hose up you get water out the prop and other relief areas in a hurry and with some noticeable flow. may just be expecting too much from this little guy. I plan to get a no contact thermometer and run in a tank in the next couple days to get a more accurate idea of what is happening. If it doesn't warm up or gets too hot then I will know better where to go next. thanks everyone for all the help its greatly appreciated. will post results soon

https://www.youtube.com/watch?v=_O68hHqJSEI Watch this video this how your motor should look.

 

[Chinewalker]

Not much water is likely to exit the relief on the back of the motor leg under the rear latch. It needs back pressure to exit there, as it is difficult for the motor to push exhaust under water at idle. When underway, there is a bit of suction on the aft end of the propeller, which helps draw the exhaust out he prop. But in neutral, at idle, the exhaust relief helps alleviate the issue of exhaust not being able to push out the prop, which would be displacing water in the lower unit to exit the prop. Bottom line, as noted above, run it on a boat to properly test the cooling system.

 

[jdhgcb]

okay so I got the motor running in a drum today used a 55 gal drum so it would hold plenty of water and not let the water warm up much. ran the motor for 40 minutes mostly at idle with a few revs here and there. the hottest the head got at the top was 99.5 degrees. the head by the plugs saw 104, the water cover over the t stat got to 98, and the side of the crankcase right at the seam got to 106. So i am led to believe either the thermostat is stuck in the open position or there is no thermostat at all.

on a side note, the exhaust relief hole under the cowl latch was spitting out water and exhaust just like the ones in the videos so I guess the motor is pumping water fine.

 

[jdhgcb]

So I've got the powerhead off and things cleaned up, and the two things I have noticed so far that I find odd are

1-the water tube directing water out of the motor seems to have been cut short. According to a parts resource the replacement tube for my engine should be about 6 inches long. the one that came off this motor is more than 3 inches shorter and wont even fit into the hole in the exhaust housing.

2-the water tube from the water pump to the motor has a small hole in the side of it. it appears to be a clean drilled hole rather than a jagged hole that may be caused by corrosion or whatever.

anyone have any of these parts laying around to confirm if mine are normal or in need of replacement?

 

[flyingscott]

There are 2 different exit tubes for that motor a long and a short one, somebody may have cut yours or replaced it.. There should be no hole in the water line between the pump housing and the block.

 

[thumbnut]

.. There should be no hole in the water line between the pump housing and the block.

The water tubes on the megaphone equip motors have a small hole in the water tube to cool the mid. The 9.9 wet leg ones do not.

 

[flyingscott]

The water tubes on the megaphone equip motors have a small hole in the water tube to cool the mid. The 9.9 wet leg ones do not.

You are correct, thank you. I had a brain fart on that one

 

[jdhgcb]

the pin hole for cooling is what I thought it might be, after reading through leeroy's ramblings, I found that they did change water tube lengths through out the years. according to johnson, mine should have a longer one. Although it may not be critical, I will replace it with the correct one for this year (might be unnecessary but I kinda have a thing for using the correct parts on an engine) hopefully I wont find anything else wrong before I get the job done.