Starboard Engine Overheating at Idle, cools down throttling up

[Wanderlust]

Hi Fellas,

The starboard engine is overheating after awhile at idle, but when I throttle up she pops back down to 165-170. I looked at the water flow from the exhaust-The port engine looks great and the starboard water flow is much less. Impellers? That is what I was thinking. I touched the manifolds and risers and the risers are not hot to the touch(But I'm eyeing them next).

I was quoted 3 hours of labor today to change them. (I am thinking to change them out for both engines), and the impeller kits were $100 each. Total about $530.00 Sound reasonable?

You guys that are super knowledgeable and are our protection against the bad guys .

Chris
Wanderlust.

[rugman]

Mine did the same thing this year . The price is what I paid

[Viper]

Ya likely the impeller. Make sure they don't simply replace the impeller but that they also find all the missing pieces if the impeller got torn up, otherwise they will continue to cause problems by blocking off cooling passages. This might happen right away or not be a problem for a while but eventually it will rear its ugly head. Tell them you want the impellers and all the pieces back so you can check if any pieces are missing.

[Wanderlust]

Hi Viper!

You're awesome sir!

I requested the old parts and will show some pictures of what they look like once the repair is finished.

Thanks for your feedback also Rugman! We never know if people are legit or they are overcharging so I prefer to ask the experts!

Chris

[Wanderlust]

The mechanic took off the raw water pump(brass) on the port engine(which wasn't overheading)and said it was very corroded and he believed he would strip the screws putting it back in He also said that the impellers were ruined on the port engine, yet this engine isn't overheating. They said the impeller on the starboard engine was fine, so they cannot diagnose the cause of the overheat. Of course, I am not there to witness this so yeah, let's add another $600 to this repair. Nicely done and well played on their part. Next time, I will be there for all repairs. Lesson #1 learned.

Chris

[waybomb]

I am soooo glad I took High School shop classes which really made my mom upset since that would make me a grease monkey my entire life. She was wrong of course, but I learned so much, which got me more interested, and now I can fix anything.
I've rebuilt my house, rebuilt many engines, rebuilt cars and boats, fixed everything myself, fixed mom's air conditioner, dishwasher, furnace, went to school and earned an A&P ticket (which I have never used professionally), and on and on. Of course, she always asked where I learned that stuff. I smile and always say "remember me that hippy kid being defiant and not doing what you wanted me to do?"

And I keep learning. You are never to old to learn. Buy some tools and dig in! Save a ton of money.

And fwiw - are you sure the one that was overheating wasn't sending its water temperature indication to the correct gage?

ps - find a new mechanic.

[Viper]

So did they actually board the boat to assess before giving you an estimate?

[Wanderlust]

Hi Waybomb,
You read my mind! I like to tinker and I will dig in. I also honest to God thought today that maybe the overheat signal was going to the wrong guage or the guages are hooked up backwards but I don't think so. I ran the port engine for 30 minutes on Friday and the guages read normal for it. I turned the starboard engine off until we took it for a ride. It took awhile but she overheated at idle and the starboard gauge read it. There was a bit of difference from the fly bridge gauge and the helm gauge (about 10 degrees). Maybe it's a thermostat?

Hi Viper,

They did board the vessel and once they took the port impellers out they called me with the raw water pump condition.

I am having the bottom scraped tomorrow. I spoke to the diver and asked him to really focus on the thru hulls to ensure there aren't any barnacles or growth.

[Wanderlust]

It was the impeller and thermostat! The thermostat was corroded shut.

Nice!

Chris

[Viper]

Glad it worked out