|Topic Review (Newest First)|
|04-15-2014 08:37 PM|
Re: Yanmar raw water cooling problem
I had a similar problem with my 1982 Yanmar 3GMD but the cause was not the waterpump. The exhaust manifold was completely filled with black rusty slime - see photo. When I cleaned the inside mechanically (screwdriver, chisel, grinder etc) I discovered that the cover was pretty much rusted through - only the rust and slime had kept the water in - I'm glad the blockage happened when I was at the dock.. I am trying to get a new manifold from Yanmar - it's only available in Japan...
That's What Was Inside The Blocked Water Passage Photo by utopf | Photobucket
Hole In Cover Of Manifold Photo by utopf | Photobucket
|07-05-2013 05:30 AM|
|The Dysfunctional Sailor||
Re: Yanmar raw water cooling problem
A bit late to joint Q&A for this problem but I have a 1GM10 and have started with over heating after a new thermostat was fitted by the yard.
I have looked at the impeller housing and semi cleaned the gunk off a very thick gasket ( could this be the reason why it was over heating, not enough build up water preassure ? )and fitted a new yanmar gasket paper. Very thin. Problem was it wouldn't seal, so I applied a layer of gasket as an emergency as I was on a swinging mooring which wasn't safe. It worked for now but it hasn't run enough to get really hot and be checked.
I will have a go and clean everything up again and do checks.
My part to the questions. Is. At what point in time after starting engine. Did the water alarm sound off.
|06-25-2009 10:26 PM|
|roline||Speed seal does offer an alternative if your willing to pay the price. I like the idea of the Oring seal instead of sealants and gaskets. Paper gasket thickness should be around 0.003" thick possible glycerin treated paper for this application. We used it for rebuilding oil pumps to prevent excessive end play gaps to produce pressure loss.|
|06-25-2009 05:42 PM|
I completely agree. Exterior strainers cause many more problems than they solve.
Originally Posted by rikhall View Post
|06-21-2009 04:51 PM|
|blueoctober||Excellent posts-very, very helpful|
|06-17-2009 08:19 PM|
|noreault||Well thanks to all. Everything seems to be in good shape (knocking on wood as I say that). At least no lost of prime since the repair. My plan is to get a raw water strainer on the inside.|
|06-17-2009 07:27 PM|
No strainer on intake
Just my personal opinion.
I don't like a strainer on the outside of the boat covering the raw water intake. I prefer a Groco raw water strainer inside. With no covering strainer I can (worst case scenario) remove the hose and shove a close hanger wire down to clear it. We have the raw water strainer inside and we can see if there is sea weed or whatever in it.
Just my personal preference.
|06-08-2009 08:59 PM|
My cover was scored (circular, from the impeller wearing it) enough that you could see it easily, and catch it with a fingernail - maybe 1/32" - 1/16" or so.
Yours sound OK. I am not a mechanic, so maybe someome else can chime in. I think that if your raw water pump and impeller are in good shape, you shoudl not have water or air bypass it. I don't think any air leaks are good. However, air is always in the exhaust elbow, yet doesn't make it's way back through the heat exchanger, and then water pump. Your possible leak is quite far down the line, so it may not be an issue. I do think any leaks / loose clamps near the pump would facilitate the loss of prime.
Let us know how you make out.
|06-08-2009 05:11 PM|
Not a lot of scoring. Some faint circular on the inside. Very little on the outer part. While definitely not a highly polished surface, but to my eye looked smooth enough for the gasket to work well.
Is it possible for pump to lose a prime from a leak later in the cooling system. I ask since when I changed the engine zinc the bolt that the zinc screws into was completely frozen. It is mounted into a small cover held on with 4 bolts. All of which moved easily. I was somewhat surprised that there was no gasket on that piece. It doesn't seem to leak, but could let air in I suppose.
|06-08-2009 12:13 PM|
|Northeaster||Sounds like you are on the right track. A buildup of old gasket material would keep the cover from being tight against the impeller. Was there much visible scoring on the inside of the cover plate?|
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