new impeller and housing ruined

[wesleyhunter]

1986 Malibu Skier w/ Mercruiser 5.7 260hp. Replaced impeller when boat overheated. The impeller was destroyed as was the housing. I fished all ( i think) of the pieces out of the hoses and heat exchanger and replaced impeller and housing. Took the boat to the lake, put it in the water and it started smoking really bad out of the intake at the bottom of the boat. Removed the housing again and it the impeller and housing were ruined again. What is going on?

 

[Bt Doctur]

Re: new impeller and housing ruined

Improper installation of the water pump or a clog someplace else shutting off the flow out the exaust. hot exaust with no cooling water melting the housing.

 

[Don S]

Re: new impeller and housing ruined

Doesn't really matter what type boat it is, it's a Mercruiser. Is it an IO or a straight inboard? Where is your raw ater pump, and is the water getting to it (raw water pump) restricted in any way (Don't assume anything, check it).

 

[Blk-n-Blu]

Re: new impeller and housing ruined

Wes, Have a look here for installation procedure. Some petroleum jelly will protect the dry start. And as Don said look for any restrictions, use the muffs to run the system without the engine running first to check water passages.
good luck.
http://www.mercstuff.com/howdoi.htm

 

[DHPMARINE]

Re: new impeller and housing ruined

Malibu Ski should be an inboard with a seawater pump.If the pump is melted (heat damage) it is not getting water. That is a given fact.Water keeps it cool.So it doesn't melt.

Either water is not getting to the pump thru the intake (or the shut off valve,or there is a severe blockage upstream of the pump,stopping all or most of the water getting into the engine,or out of it.

What is the history of the boat ? (had a long time,just got,sat awhile,etc.)

DHP

 

[wesleyhunter]

Re: new impeller and housing ruined

Wes, Have a look here for installation procedure. Some petroleum jelly will protect the dry start. And as Don said look for any restrictions, use the muffs to run the system without the engine running first to check water passages.
good luck.
http://www.mercstuff.com/howdoi.htm

I got it Sept of 2005. Only ran it a couple of times last year before putting it up for the winter. As far as I know, it was a one owner boat and was well maintained. It is very clean, but you never know.
I guess I can run water at a good rate thru the outgoing hose of the impeller pump and see if I get anything out of the exhaust or does the mtotr need to be running?