got the bill from mechanic. is this reasonable?

[Blind Date]

An engine from the 90's, probably hasnt been replaced from new.. they dont last forever.

Pretty sure the engine pumps don' wear out. The bearing fails and they leak but there is nothing with the pump itself to wear out unless the impeller has corroded to nothing. Maybe in that salt water crap but unlikely in a fresh water boat. In addition the engine pump doesn't do squat anyways, that's why they make kits to completely remove them. The seawater pump can easily move enough water through the engine & manifolds to keep everything at operating temp.

In an older boat/motor I'd be looking for a blockage some place due to corrosion and would start at the risers. I suspect the engine pump is just fine and not the reason for the overheating issue.

 

[roffey]

The water pump on my 4.3 2014 Merc failed. I think the pump seized and the pull of the serpentine belt destroyed the pump. Other than a horrendous noise and after the pump failed there was little to indicate a problem. What I did notice was if the boat was at idle it would heat up very quickly but at speed the temps were normal. My point is the pump did fail and it is required.

 

[bruceb58]

My point is the pump did fail and it is required.

What did the impeller look like?

 

[roffey]

What did the impeller look like?

The one in the out drive I did not check as the boat was new new, less than a year old. The pump on the block was covered under warranty and once more I did not check my self. I have a story on this repair as it took a month to fix. Anyway not going to hijack this post, that story will be for another thread, lol.

 

[bruceb58]

Yes, I was wondering about the one on the block. I have never ever heard of a block mounted water pump fail in a way that wasn't a bearing or seal.

 

[gmajorabm]

the impellor looked brand new it was replaced and had maybe 6 hrs on it. called the mecanic he said to take the boat in so he can check it out. i had the boat docked at a pretty shallow cafe maybe 2-3 ft or less of water. mecanic said i could have sucked some mud into the lines?

 

[Fun Times]

^ Oh yes gmajorabm, having clogged up water passages from shallower waters could be an issue for your overheating situation.

Though it's rare; 'The front circulating water pumps eventually do begin to breakdown for various reasons stopping proper water circulation but the most common issue is the pump leaks out the weep hole mostly just causing a watery mess.

There was a specific warranty issue back around 2012 to where the circulating pump impeller on most (or all) marine engine brands became defective and would cause overheat type issues at what seemed like unusual running conditions at either high or low RPM from what I recall Mercruiser saying about it....Mostly low RPM it seemed though which helps indicate their importance for cooling as long as it's mounted emplace. The only online info that I'm aware of was from PCM which is quoted below for better reference including a photo of the cracked/broken impeller.

Don't believe I read anyone mention possibly having something along the lines of a stuck closed or clogged up thermostat within the housing which could be a culprit too.

From PCM:

In the event you are diagnosing an overheat or running hot condition, the engine circulation pump should be tested and inspected prior to extensive diagnostics.

PCM is issuing Service Update SUP2012-03 to address a problem with 5.7 engines.
General Motors vendor for the circulation pump has supplied some pumps with impellers that do not meet the "hardness" spec on the metals. The impeller metals in some cases are too hard. This condition results in the impeller cracking and is no longer able to circulate water through the engine and exhaust system. The crack can be anything from a hair-line crack to completely broken as shown below.

 

[roffey]

Yes, I was wondering about the one on the block. I have never ever heard of a block mounted water pump fail in a way that wasn't a bearing or seal.

I'm fairly sure mine was a bearing... or at least sounded like it

 

[Blind Date]

Yes, I was wondering about the one on the block. I have never ever heard of a block mounted water pump fail in a way that wasn't a bearing or seal.

Me either, marine or automotive application.

Here's a link to buy a crossover kit for a marine V8. It completely eliminates the engine mounted water pump to save horsepower. If they're necessary to keep the engine cool explain to me how why they sell such a thing.

[FONT=&quot]At last you can finally purchase a crossover for your serpentine belt driven EFI motor. Until now there was no way to reap the 15 to 20 horsepower gain that could be achieved by removing the unnecessary power robbing circulating pump. These beautifully polished crossovers allow you to retain your factory serpentine drive belt through the use of a clutchless freewheeling billet idler pulley. This unit is a perfect addition for any EFI motor. If you want great looks and performance while retaining your OEM drive system, then this product has you covered.[/FONT]

http://www.cpperformance.com/products/Cooling_System/crossovers-stainless.htm

 

[gmajorabm]

ok thanks guys for the responses i will see what the mecanic says. was hoping i could do a quick fix but i think id rather have him mess around with it outta fear i might ruin something else