Impellor Swelling over Winter ?

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jakeroyd

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I normally change the water pump impellor at this time of year (along with the oil and fuel filters etc. )and use a cheap neat antifreeze to fill the system for Winter (raw water system). I now find I am not supposed to do this because the new impellor can absorb the antifreeze and swell causing maybe premature wear or failure next season. So maybe I should leave the old one in over Winter and replace it in the Spring. Engine is a Yanmar , always genuine Yanmar parts.
Any Forumites had any problems with theirs swelling ?(impellors I mean of course !)
 
There are different types of impellor material though I don't think that Yanmar tell you what theirs are made of? If you buy Johnson impellors you can select nitrile which (I seem to recall but you can check on the Johnson site) is immune to most chemicals. Wouldn't it be possible to drain the system instead?
 
Just leave the impellor out and refit the end cap, then you are safe and sure! If the old one swells, which they do, it might be a pig to remove later.
 
Some folk advise that you take the impeller out for the winter, certainly if you plan to use it again the following season. Helps stop the blades setting in one position during the long period of no running.
 
[ QUOTE ]
Some folk advise that you take the impeller out for the winter, certainly if you plan to use it again the following season. Helps stop the blades setting in one position during the long period of no running.

[/ QUOTE ] ...while yet others suggest turning the engine over by hand, if that's possible, once a month or so. Also serves to distribute oil around a bit and it's what I favour. From the impellor-preservation POV I suppose one should always make sure the crankshaft is turned an odd number of revs to make the impellor rest in alternate positions.
 
Entirely agree with you and Cantata. If you are going to leave the cooling system filled, simply take the impeller out and replace the face plate. Agree with turning the engine over a few times during the winter - we use our starter motor to spin it over with the decompressors on which allows sufficient oil pressure to build up to distribute oil to the majority (if not all) of the sufaces.

That said, we always drain our RW cooled engine having recirculated a bucketful of water laced with an emulisifying oil for about 10 minutes to coat the internal waterway surfaces. So during our layups the impeller is out and we don't need to even replace the face plate.
 
Hi

Usual well meaning bollox here!
Talk to jabsco or Johnson for correct info
Yes all impellors swell
yes some are nitrile which is only oil resistant not chemical resistant and should not be used in engine cooling applications only in bilge and macerators!
and has lower life and is more brittle and will not tolerate any dry running at all!
Neoprene is recomended as used by johnson/Jabsco beware cheap impellors with obscure elastomers!
Cange every year in the spring do not dry out on radiator as makes compound brittle and weakens the bonding between insert and impekllor and carry a spare
Various cases of impellors spinning on insert every spring always blamed on manufacturer. Ie yanmar 1GMs it is because impellor has multi blade and longer blades to get quantity water needed therefore needs a lot of start up torque and is less tolerant of swell.
 
Just to offer an alternative:

My impellor was changed when I bought my boat in 2001 and has done 100hrs plus every year since.

Engine is a 4107 with a temp gauge and easy access to the housing.

I know that everyone will tut tut and tell me what a risk I am taking etc but i do my own maintainance and keep a good eye and ear on the entire installation.

Not the way to go for every one, but it does rather show how long these things will last if they have to.

Regards Nick

BTW I did take it out a while back just to make sure it wasn't stuck on the shaft...it looked pretty good so I put back again.
 
Well to be honest, I change my impellors every two years, I keep the old ones if good as spares, then bung the old ones away, when I change the ones in the engines, I also have quick release end plates, if you know what I mean, this way I always have spares and I know the ones in the engines are good. I also have halyard exhaust warning thingies fitted. I tend to be a belt, braces, piece of string and safety pin type of fella me'sel!
 
when you do your own maintainence, do you just change oil, filters check belts and impellors or do you delve further, like checking valve clearances?, now there is no resident engineer at Wicor, I am tempted to do it myself but not so sure about fiddling inside the engine, vetus 42 HP 800 hours
 
Doing valve clearances isn't a big deal. If you ever did it on your car, you know how to do it on your boat, give or take a few details that the service manual should give you.

Others above have suggested turning the engine over to coat everything with oil. I'm unconvinced about this. You're drawing damp cold air into your cylinders, which probably aren't going to get much oil at hand crank or starter speeds, and on to the valve seats which won't get any and have no protection from rust. To my mind, it's much better either to leave it alone or start it and run until fully warm, which is what I do around once a month in winter.

I know someone who turned the donk over from time to time during the winter and had a helluva time getting it going in spring, probably due to poor compression caused by corroded valve seats. It took loads of easystart to get it going, but ran fine after than, starting from warm OK, but still needed easystart from cold for some time. It did recover after a couple of weeks regular use, but a serious scare!
 
Hi John

I do all my own maintainance on the old Perkins, however so saying that has been very little so far.

Valve clearances for example...the engine has done 800hrs since a total rebuild..it had 50hrs when I bought her..and I havn't had to look at the tappets yet..they sound okay !

I do always take a look over the engine before or after use and have a listen with the 'floor' open. I also run my hand over variuos bits and pieces, ie aux belt and other bits that may be prone to wear of coming loose.

Typically, I found a loose engine mounting bolt at the front end of the engine out of sight..that was great as I had been feeling that it was running a tad rough.

One thing I do always do and that is change the oil ( not filter) mid season at approx 50hrs I recon that equates to about 2500miles of gentle road use.

I like having an engine you can sit on!
 
[ QUOTE ]
..and I havn't had to look at the tappets yet..they sound okay !


[/ QUOTE ] And you can hear tight tappet can you? Do you ever remove the impellor and check it, or leave well alone?
 
everyone will tut tut - not me, changed mine 10/3/03 and it is still giving good service.
I check it annually and carry a spare, it's only about a 20 min job to replace.
I am not of the replace knacker or not fraternity, as new items can also fail.
 
I hear what you say.....but I have been listening to old engines like this for quite a while and would be quite happy to listen to the engine for that sort of servicing... Anyway push rod engines very rarely tighten up on valve clearence.

BTW I understand that many motorcycle dealers will 'service' check valve clearances in the same way .. ie give it a good rev... sounds okay to me Fred !

I think its a horses for course thing! If you have always done this sort of thing its fine, but if you have always taken your pushbike / scooter/ car / lawnmower to the shop to be fixed its probably not the time sort of thing to start practicing on..

regards Nick
 
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