Steam from tell tale

[RedLunder]

I am new to this forum, but have enjoyed reading many times. I have a 1984 50hp Mariner (4cyl). I have had recent steam that has been coming from tell tale - especially WOT - also at that time the flow of water from tell tale stops coming out....when i slow down to idle - gradually water will resume coming out, but it is sporadic and then finally resumes, but water is very hot and is obvious the motor is running hot.
I pulled lower unit and checked the impeller, which is in excellent shape (i replaced it last year). Over the last year the pressure of water coming from tell tale has always seemed to have low pressure, but nothing like this and no overheating issues.
I was stumped - thinking the water pressure should increase with increased rpm's, but its exactly opposite. Any ideas or thoughts?
I'm pretty sure this motor does NOT have a thermostat, but am not 100% sure. I've looked up in a parts diagram and it shows no thermostat?
Any suggestions would help
Thanks
FYI SN# is A161259

 

[minuteman62-64]

I had a similar problem with my '82 30 HP Mariner. After checking all the innards, I realized that, when I had the motor off the transom for some service, and reinstalled it, I inadvertently put the tilt pin in a different hole than previously. The new position resulted in a "bow down" trim (which also meant "stern up". Sure enough, took it out for a run and at high RPM the water intake came right up out of the water. Moved the tilt up one hole and problem was fixed.

 

[RedLunder]

Thanks for reply. sounds interesting. I dont think I'd have the same problem if I hadnt removed the motor recently right? It does have power t/t. Not sure that I messed with it all that much when I was driving it.....the motor was all the way down in the water...

 

[RedLunder]

Thanks for reply. sounds interesting. I dont think I'd have the same problem if I hadnt removed the motor recently right? It does have power t/t. Not sure that I messed with it all that much when I was driving it.....the motor was all the way down in the water....

 

[minuteman62-64]

Thanks for reply. sounds interesting. I dont think I'd have the same problem if I hadnt removed the motor recently right? It does have power t/t. Not sure that I messed with it all that much when I was driving it.....the motor was all the way down in the water....

Yeah, probably not the issue in your situation.

Only other idea I can offer: I had an impeller with the inner bushing cracked. At low rpm would work fine. Crank it up and the key would slip in the impeller and no water pumped.

 

[Texasmark]

Yeah, probably not the issue in your situation.

Only other idea I can offer: I had an impeller with the inner bushing cracked. At low rpm would work fine. Crank it up and the key would slip in the impeller and no water pumped.

That sounds like his problem. His diagnosis really had me going for a minute with no stat or popoff to fail.

Mr. Lunder, you might ensure that your antivent plate, just above the prop is at or near the surface of the water when you are running at WOT. That would ensure that you weren't having the same problem as minuteman. With no stat your pee shouldn't get much above warm, even in the summer and as you said volume/pressure should increase with rpm increases.

Mark