9.8 2 stroke Nissan cooling/water flow question

[platothetoad]

I recently acquired a 1999 2 stroke nissan, model NS9.8B. I got it running and noticed that when running in the yard with muffs SIGNIFICANTLY more water is exiting the upper exhaust port just under the powerhead than either the telltale or the prop. It's like a faucet. I've included a video of the motor running for clarification.
What could be causing this? A blockage in the leg somewhere? Is it a problem, or mostly cosmetic? The motor ran like that for 15-20min and never seemed to get too hot.
Any insights are appreciated. Thanks.

 

[Sea Rider]

Engine sounds in excellent running condition, at least with no load, that's not pushing a boat. If that water port is metal and not the plastic hose type, introduce the red cannula that comes along W40 all the way inside telltale, spray an overdose, let penetrate, poke same cannula or a plastic tie & wrap back and forth to clear slight salt/debris obstructions that usually builts around inner telltale hole.

For peace of mind and wallet, better replace the whole water pump kit, you have a 22 year oldie, impeller blades could break inside housing and have an unwanted severe overheat. You could add a thermostat removal to check it's condition, clean it, remove all crusts if any. If severely salted or rusted, put a new one along new thermo gasket.

With engine on on muffs check back water port exiting water with hand, you should feel warm-cold cycles, means therrmo is working properly. If has just erratic warm or cold cycles, change thermo, has issues. One thing is sensing temp at idle other working on a boat at speed.

Those Tohatsusu are excellent engines, but needs to have all water circuits and cooling related parts running top for best overall engine performance.

Happy Boating

 

[platothetoad]

Thanks for the input. I'll do some probing around and see if there is anything blocking either the tell tale or exhaust port, though I kind of doubt it based on volume of water coming out of each. I assumed, again based on the water volume exiting the motor, that impeller was in good working in order. Could this not be the case?

 

[TOHATSU GURU]

As you increase RPM more of the water exits through the propeller housing. At low speeds it is normal to see more at the upper port.

 

[platothetoad]

Thanks for the reply. I figured all was probably ok, it was just more water than I'm used to seeing coming out of the exhaust port on my other motors (8hp yamaha, 4hp evinrude). Everything else on this motor seems to be in tip top shape. Just needed some reassurance that the water flow was ok too.

 

[Sea Rider]

If handy, check impeller, after such long elapsed years coud be dry, hardened, cracked, you never know...one thing is pumping at idle/low rpm, othen at high wort rpm when engine needs max water cooling.

Happy Boating