25hp not "peeing" constantly

Was getting outfished by my 8 year old yesterday, which I LOVED. Let her drive for a while (sitting bedside her) I looked back at the engine and noticed it would peee for a while, then taper off, start again. repeated this cycle. Gave it a little more gas to see if would change. The on again off again cycles closed up. Water Pump? Is there a thermostat? Im probably due for a new water pump, been about 5 years. What is the lifespan on a water pump?
Water temp 86 degrees f. '95 25hp merc, ser# og157655.

Also, After it sits for a couple of weeks I have to squirt gas in the carb for a while to get it to keep running. After a while it will run on its own just fine. Went out thursday night and had this problem. It started on the second pull Saturday with nothing added to the carb. Was wondering about the whole ETHANOL thing. Have been adding seafoam on every tank, but just read a post about seafoam killing an engine.
Thanks ahead of time for any input.

Every time I look at the impeller on one of those, the vanes are cracked.-----------------Time to install a new impeller on yours.

Change the impeller. About 3 years is the max life on them before you are "rolling the dice" as to when they will fail.

The post about the Seafoam was mine - it was a sarcastic post.

And don't worry about the ethanol. Keep the gas fresh(under 2 weeks old) or stablized (or both) and it will no be an issue.

I respectfully disagree about the ethanol comment. If I don't run my motor out of gas when I'm done for the day, in less than a week my float needle will be stuck abd I'm ripping carbs down again..

I will get some parts to change out the impeller, anything i need to be aware of or is it a pretty straight forward job? Hotrod53, Do I need to start runnning the fuel out after an outing? Can I ASSuME that is my problem for starting after it sits for a couple of weeks?

When I load mine on the trailer I pull the fuel line connector at the motor and raise the idle a little with the fast idle. If it's not your problem now, it eventually will be.

You will need some vice grips to turn the driveshaft when you install the impeller. Don't use oil or grease on the new impeller, use dishwashing liquid. It will all soap up and blow out on the first run, oil and rubber are never a good match. Check you other parts and pieces when its apart, I had to change my impeller cup on my last change.

Thank you to all for your help. Getting some parts ordered. Will start running the fuel out after each outing.