15hp Mariner Tell tale at high speed ?

[bill stallings]

My 15hp 1994 Mariner at full throttle going down the lake will pee hard for about 20 seconds and drop off to nothing for maybe 10 seconds and pee hard again.I havnt had the motor long and while duck hunting this morning I got stuck on the bank and pushed alot of mud.Is this intemediate stream at full throttle normal or is it plugged up? Not familiar with this motor actually.Does this sound like a impeller gone bad?
Thanks

 

[Barnacle_Bill]

Re: 15hp Mariner Tell tale at high speed ?

If you don't know when the last time the impeller was replaced, replace it and the thermostat. Good time to flush everything out that you can too.