How to test an inpeller ???

matthew colgate · Feb 20, 2011

Ok after my first post of questions I was advised that I might have an impeller problem and after researching where it is and how to do it , Before I dig into it I have a question is there a way to test the impeller to make sure thats my problem before i go replacing it ? Thanks in advance for any advice and help given .

matthew colgate · Feb 20, 2011

Re: How to test an inpeller ???

sorry guys forgot I have a mercruiser mcm140 inboard in my boat

Don S · Feb 20, 2011

Re: How to test an inpeller ???

Very simple, If it has a year on it, and you have it out to look at it, replace it. Replacing every other year is a good rule of thumb.
To check it, if it looks ok and there is no cracks or damage to the edges, and the vanes straighten out in 15 minutes, it's good to go.
You will need new gaskets rather you replace the impeller or not.

matthew colgate · Feb 20, 2011

Re: How to test an inpeller ???

so there is no way to test it to see if it is working without tearing it down ?

Bondo · Feb 20, 2011

Re: How to test an inpeller ???

matthew colgate said:
so there is no way to test it to see if it is working without tearing it down ?

Nope,... Not really, which is Why I suggested you Replace it...

matthew colgate · Feb 20, 2011

Re: How to test an inpeller ???

okie dokie guess im replacing it ......... Just so I got this right the impeller is what draws the lake water into the engine right ? And if I ran it yesterday and cracked open the pitcock on engine block and it still had coolant in block instead of lake water the impeller would cause that therefore thats the reason the engine temp went to 190-200 degrees ? Dont mean to be a pain Im just trying to make sure I understand , I guess thats the downfall of being a newbie lol

Bondo · Feb 20, 2011

Re: How to test an inpeller ???

Ayuh,... Do you have a set of Muffs yet for testing, 'n flushing your motor/ drive,..??

If so,... Put 'em on, 'n fire it up...
You should have a steady stream of clean freshwater comin' outa that drain plug in a matter of seconds...
If you insist, pull the hose from the outdrive that hooks to the T-stat housing,...
You should see an ample flow of water coming from it...
The actual amount, 'n height, should be in the Manual I gave ya yesterday....

matthew colgate · Feb 20, 2011

Re: How to test an inpeller ???

Yeah im going to get muffs after work tonight just dont trust the bucket or tub way ........... I do believe though I have been pointed in the right direction if the impeller was operating properly the engine block would have had water in it instead of coolant

artificialreef · Feb 20, 2011

Re: How to test an inpeller ???

He sounds confused, if there is coolant in the block, isnt that a closed cooling system with a heat exchanger. The coolant stays in the block.

Bondo · Feb 20, 2011

Re: How to test an inpeller ???

artificialreef said:
He sounds confused, if there is coolant in the block, isnt that a closed cooling system with a heat exchanger. The coolant stays in the block.

Naw,... Matt says it's a Winterized 140hp, 3.0l...

matthew colgate · Feb 20, 2011

Re: How to test an inpeller ???

The guy who i got it from filled engine with coolant when he winterized it ......... Not really confused just new this is my first boat if its an auto/Diesel car or truck I got the knowledge and experience been a grease monkey for 10+ yrs but never have done much with marine ......

matthew colgate · Feb 20, 2011

Re: How to test an inpeller ???

yeah the more i think about it I know the guy i got it from didnt change it and the guy who had it before him didnt mention changing it when i talked to him and he ran it all season last season so im hunting a kit down found one on ebay for 23.99 plus shipping comes with everything even a new housing if its the correct one that seems like a pretty good buy from what i have seen

Bondo · Feb 20, 2011

Re: How to test an inpeller ???

matthew colgate said:
yeah the more i think about it I know the guy i got it from didnt change it and the guy who had it before him didnt mention changing it when i talked to him and he ran it all season last season so im hunting a kit down found one on ebay for 23.99 plus shipping comes with everything even a new housing if its the correct one that seems like a pretty good buy from what i have seen

Ayuh,... I believe they have the same kit, for about the same money, Right here at iboats megamall....

matthew colgate · Feb 20, 2011

Re: How to test an inpeller ???

Bond-o said:
Ayuh,... I believe they have the same kit, for about the same money, Right here at iboats megamall....

Really ? how do i get there to check it out ?

Bondo · Feb 20, 2011

Re: How to test an inpeller ???

matthew colgate said:
Really ? how do i get there to check it out ?

Ayuh,... Top left corner of the page, click the button that says "Marine Store",...
Then keep clickin' the links, goin' your way...

matthew colgate · Feb 20, 2011

Re: How to test an inpeller ???

Ok so I have another question I know my outdrive is an Alpha One but the decal for the serial number is there but theres no number Im guessing it rubbed off or somthing how do I know what kit I need if the serial number is not readable ?

Don S · Feb 20, 2011

Re: How to test an inpeller ???

Go to the top of this forum, click on the adults only thread. Then click on the Merc Info thread and there is a Merc ID and history link.

matthew colgate · Feb 20, 2011

Re: How to test an inpeller ???

ok thanks alot Don I appreciate it

Fireman431 · Feb 20, 2011

Re: How to test an inpeller ???

Just a quick question:

If you are going to pull the outdrive, open the housing, and remove the impeller for inspection....why would you just not spend the $15-$20 and replace it and know that it's good?

I have 3 in my boat (2 in engines and one in genset) and they get replaced every 100 hours. Period. Solid piece of mind.

sethjon · Feb 20, 2011

Re: How to test an inpeller ???

matthew colgate said:
Ok after my first post of questions I was advised that I might have an impeller problem and after researching where it is and how to do it , Before I dig into it I have a question is there a way to test the impeller to make sure thats my problem before i go replacing it ? Thanks in advance for any advice and help given .

You don't check an impeller. Its too cheap. If you pull it out, replace it and have no worries for the season.

How to test an inpeller ???

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