Mers 5.7 temp question

[fkonieczny18]

I know, I know, not another temp question. I did search but didn't find anything with the same scenario. The outdrive is brand new from sterndrive.cc so i know the impeller is fine. The temp is fine when running on the lake (Lake Michigan), but when at idle through the river to the public ramp the temp shot sky high to about 220-240. It's a 1986 Wellcraft Nova 23XL w/ a Merc 5.7 and Alpha I Gen I outdrive. Someone had mentioned soemthing about the sea pump. I'm not too sure what that is. Is it a marine term for a water pump? (no laughing allowed). What could be the cause of the temp spike when idling? Any thoughts? Thanks!

 

[tommays]

Re: Mers 5.7 temp question

your pump is in the drive and you problem sounds like low water flow<br /><br />was there a cooling problem with the old drive??<br /><br />its brand new BUT if it was run dry at all it will be damaged<br /><br />when the upper and lower were put toghter its posssable to not get the water tube coupling correct and leak <br /><br />tommays

 

[Haut Medoc]

Re: Mers 5.7 temp question

If you have a new out-drive the impellar should be new and not a problem. Quick way to check that is to remove the water feed on the inboard side, and check for water flow there. My guess is you'll be O.K. there. You didn't say if you are raw water cooled or FWC... I would look for a restriction @ the risers. They are pretty small holes that clog easily, and drastically reduce water flow especially on raw water engines. That's where to start.J

 

[Bondo]

Re: Mers 5.7 temp question

Ayuh,.........<br /><br />If the Impeller(seawater pump) Is in fact Good,.....<br />That leaves the Rest of the Cooling system to be Restricted Somewhere..........<br /><br />I'd start like kopec says,.. At the In-coming line.... Maybe an Old pc. of the Old Impeller is lodged somewhere.......<br />Or the exhaust Risers/Elbows......<br /><br />The system has to not only move water Into the system,... It needs to be able to Flow Out.......

 

[bigbrownbuku]

Re: Mers 5.7 temp question

would only take 1 plastic bag over your intakes for a very short time to kill your new pump. use the tips mentioned above and troubleshoot your sytem a little.<br /><br />the seawater/raw water pump is half the system. the engine also has a circulation pump.

 

[Scaaty]

Re: Mers 5.7 temp question

Originally posted by BenC:<br /> the seawater/raw water pump is half the system. the engine also has a circulation pump.

I think Ben got it figured here. When was the last time you put a new Circ pump on it? You said an 86...bet ya thats the problem. AND get a MARINE pump, not automotive. $100 and your floating pretty cool (pun intended!)

 

[fkonieczny18]

Re: Mers 5.7 temp question

I just got the boat, so as far as I know, the circulating pump could have never been replaced. I will start with the tips you guys mentioned. I am not a mechanic, but I have a feeling that it could be the circulating pump on the engine only because the drive is new and installed be a Merc certified mech at a very well know dealership. I would think they installed it correctly, but you never know. They make mistakes too. Thanks for the responses. Any other input is still welcome.

 

[Bondo]

Re: Mers 5.7 temp question

I have a feeling that it could be the circulating pump on the engine

Don't Waste your Time.......That pump either Works,... Or Leaks..........<br />That Ain't It......<br /><br />You've got a Flow Restriction,......... Find It,+ Your Problems Will Go Away................

 

[fkonieczny18]

Re: Mers 5.7 temp question

Cool, I will check the water feed hose on the inboard side and see it I get water there. If I get water coming there fine, I know there is a restriction somewhere.