15 hp leaking water from bottom of powerhead

[Tpainter81]

1975 evinrude 15 hp. Just did a fair amount of work to this motor. Got it cheap. I put new water pump. I added a tell tail. Carb had been recently rebuilt but whoever did it forgot to install low idle jet on carb. Guy said it ran poor. I’m not sure how it even ran at all. Got it running good and noticed water leaking from thermostat cover. I replace thermostat and put new gasket on cover. I started it up and it ran good. Then noticed water dripping from bottom of motor. I increased rpms and leak got worse and motor started sputtering and died. Then it’s very hard to start up again. Several pulls and still won’t run good. Went back to it later and started up and did same all over. Water is not coming out of original hole very well either. It comes out of the tell tail very strong though and motor is running cool when it is running. So do I need to just remove powerhead and change gasket or do I have other issues? Thanks

 

[F_R]

Those motors had many poor-running issues when brand new. Your water leak was not one of them.

 

[oldboat1]

The water cover and gasket are difficult to replace on that motor unless you remove the head, and do the water cover on the workbench. The leak may be coming from the bottom of the water cover (likely the lower left).

 

[Tpainter81]

Yes the water is seeping from very bottom left. I can see it spray out when rpms go up. When it does that it starts running bad. Are the two related or separate issues?

 

[oldboat1]

Take off the head and remove the t.stat cover. The bottom two head bolts have to be loosened but left in place while head is lifted out vertically (no clearance to fully remove them while head is in place). On the work bench, remove the the t.stat cover. Resurface both the head and the t.stat cover as they warp. Use a piece of glass or something similar, and a full piece of wet/dry sandpaper (200-400 grit). Wet the backside to hold it in place, them rotate the mating surfaces in a figure eight motion until you get a uniform shine. You will probably need a new head gasket and one for the t.stat cover. Torque to specs when reassembling.

[ed. see you replaced the head gasket earlier -- check it out, but probably ok for reinstall. Biggest issue would likely be potential overheating, which may be happening when the motor begins to run poorly. Not sure whether your tell-tale addition might be an issue -- probably not.]

 

[Tpainter81]

I fixed the t stat cover leak. It’s all good. This leak is where the power head mates with lower unit.

 

[oldboat1]

Remove the powerhead with the inner exhaust housing. Remove the inner exhaust housing, and replace the powerhead gasket.

 

[Tpainter81]

Looks like not to bad of job. But why is the motor running poorly when this starts leaking. Seems like once thermostat opens it runs poor and is hard to start. Otherwise when it’s cold it will fire right off 1st pull.

 

[oldboat1]

Change in back pressure, maybe? Possible water is sneaking into a cylinder somewhere. Guessing.

 

[Bosunsmate]

Look at your sparkplugs, i suspect water entering cylinder. One sparkplug may be clean (ie water looking clean) or if its sat a few days itl be slightly rusty from the water.
You can also detach the LU and run it for a little while with no water, thatl prove if its water related or not