Mercruiser 496 big block issue

[Matt@fullcount]

Hi all, need your help again! We’ve had a mechanic trouble shooting an issue with our starboard engine for the past few days and can’t seem to solve the issue. Starboard engine water pump has been replaced and is pumping water but it isn’t pumping through and out through the exhaust. So engine keeps getting too hot. Any ideas? Sea Ray 390 express cruiser with 2006 Mercruiser 496 engines.

 

[techmitch]

Hi all, need your help again! We’ve had a mechanic trouble shooting an issue with our starboard engine for the past few days and can’t seem to solve the issue. Starboard engine water pump has been replaced and is pumping water but it isn’t pumping through and out through the exhaust. So engine keeps getting too hot. Any ideas? Sea Ray 390 express cruiser with 2006 Mercruiser 496 engines.

Possible clogged heat exchanger.

 

[joeyleggz]

Explain how you know it is pumping water out of the water pump did you remove the hose and watch the water pour out? A simple error that a lot of people make is the strainer Does not get tighten back down properly and you’re sucking air, its one of the first signs you don’t see water being discharged out of the exhaust port. How did the impeller look from the water pump that you just replaced? If it was not all intact you will find pieces of the impeller have gone down stream and clog somewhere else :IE heat exchanger, oil cooler ,tranny cooler etc.

 

[Matt@fullcount]

Thanks to you both for the quick response. It appears that pump just wasn’t priming. Mechanic disconnected hose again and used his finger to plug until enough pressure built. Now it’s pumping through and temp is back down and steady. We’re going to take her out in the morning and see if it stays.