NS90A ran with no water for 15 seconds!?!?!?

smuller82

Recruit
Joined
May 25, 2020
Messages
4
First post and man do I feel like an idiot! I’m not a new boat owner but made a rookie mistake and need some reassurance I didn’t screw something up. So I replaced the water pump on my 2000 NS90A after it had been giving me low pressure alarms. It definitely needed it because at some point the impeller cover started spinning inside the pump cover and started melting it. All went well with the repair. I greased all the water pump parts including the impeller so that the first start ups wouldn’t be dry. Hooked up the muffs, turned on the water and she fired right up and peed like a champ! That was the day before yesterday.

Yesterday I was getting her ready to take out and I like to fire her up before we leave to make sure all is well. However I missed the most important step: forgot to turn on the hose! I checked my Ring camera and she ran for exactly 15 seconds at idle until I shut her off. You can hear me say “you’ve got to be kidding me!” On the camera. I beat myself up for a minute, turned on the hose and she fired right up and spit just as good a stream of water as the first time I ran her. We still took her out and she ran fine with no alarms and peed a strong stream the whole trip.

Sorry that was so long but wanted to give the whole story. I’d hate to snatch the lower unit off just to check and see I’ve done no damage but I will if that’s the smartest thing to do. I’m hoping since I greased everything with good quality marine grease and ran it with water the day before that 15 seconds didn’t hurt anything. What do you all think? Thank you in advance for your responses!
 

KD4UPL

Senior Chief Petty Officer
Joined
Feb 13, 2010
Messages
678
If you ran it in the water (not just on the muffs) and it didn't overheat then it's fine.
 

smuller82

Recruit
Joined
May 25, 2020
Messages
4
Yea we ran it all day yesterday and it never set off the alarm (which it was doing before I replaced the water pump) and it spit a strong stream all day. I’ve worked hard to get this engine running the way she does and I work hard to keep her in tip top shape but I’m by no means a mechanic. I just felt like such a bonehead! Thanks for the reassurance!
 

MattFL

Master Chief Petty Officer
Joined
Oct 20, 2010
Messages
867
The grease in the pump would have saved it from melting for such a short run, and the motor certainly would not overheat that quickly. If it makes you feel better, here's a story. Shortly after I bought my first 4-stroke Honda in 1999 (very quiet), when hauling it out at the boat launch my brother drove it onto the trailer then I drove him and the boat to the staging area to get ready for the road trip home. As I walk to the back of the boat I hear put-put-put-put..., yes he forgot to turn off the motor and neither of us noticed for at least a solid minute or two, and the motor was already hot when it came out of the water. So that was back in about 2000, the motor is still going strong today 20 years later. Although I do remember when I did the water pump service, the bottom of the impeller was slightly melted and the plastic housing under the lower wear plate was slightly melted, but even with that minor damage it was still pumping fine.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
The only way you can melt a Tohatsu impeller is if the motor was running full hammer down for 15 seconds with a dry impeller revving inside its liner due to a lower leg water intake kelp, plastic bag blockage.. Seen motors running for way more than just 15 seconds at idle, fast idle with 0 issues so far....

Happy Boating
 
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