Mercruiser 5.0 (2000). 0M012817. Overheated tonight

[rick3452]

Hi everyone I've been using the boat for the last several nights in a row no issues at all always rain at 160 . tonight when I launch the boat just started idling down the river I noticed a lot of air bubble sound coming from the back at the waterline shortly after that the temperature started to overheat. I returned to the dock the manifold were very hot. It does have a bravo three but I also had installed two years ago a through hull seawater pick up to add additional water to the system which has been working perfectly . Does this sound like a bad impella to you guys?
thanks for your help much appreciated !

 

[alldodge]

Does this sound like a bad impeller to you guys?

Yes, That would be the first thing to check. If you have a sea strainer see if its clear.
When was the last time the impeller was replaced?

 

[thumpar]

Impeller always comes to mind first. With the air bubbles I would check all the hoses to make sure that the impeller is not sucking in air.

 

[rick3452]

Thanks guys! I replaced the impella kit today it was completely torn up. I did a good back flush and it ran perfectly this evening. Most of my running is in the intercostal around 1000 rpm. Hate to admit it but it had 500 hrs on the impella. I've put over 2000 hrs on it in 7.5 yrs. thanks again
like most it was a horrible job. Definitely going to change to a crankshaft raw water pump