Tell Tale Acting up on 1996 Mercury Mariner 40 HP

[BlackPointBoater]

Having an odd issue with my outboard. The tell tale mostly spits steam when the outboard is in neutral or at slow speeds. If I give it speed or use the warm start lever at full crank for a few moments, it will eventually start spitting a strong stream. This stream will then maintain at a lower speed and even neutral for a few minutes, but eventually reverts to steam, unless I maintain speed.

I have had one instance where the motor must have overheated, and shut off for about 10 minutes.

Any idea what this could be, or where I should looked first?

Thank you!

 

[Texasmark]

Time to replace the impeller in your water pump...blades either have a kink from sitting up, or tips worn off from usage. Get a meanual. I boats sells them......top of the page, electronic or paperback. I used electronic, available as fast as you punch in your CC numbers. Can rent for a time duration, or buy the whole thing.