Yanmar 1GM10 - Impeller problem

[mattyc]

Originally Posted by a64pilot

I wouldn’t use any kind of grease.
I’d use surgical lube AKA KY jelly, or glycerine or dishwashing liquid as all are water soluable, while grease is not, and many greases attack “rubber”
It’s in parenthesis cause most of what we call rubber is some form of plastic and not natural rubber, but grease will cause many forms of it to deteriorate.

However I doubt lube caused your issue, and I doubt engine turning backward on shutdown did either, cause that is very common no matter how many cylinders you have.
It’s not uncommon to take the cover off and see half the blades backwards.

I think you got a bad batch, or just possibly maybe the incorrect impeller part number?

I have been using dishwashing liquid but thought perhaps silicone grease would be better. Grasping at straws at this point. My spare impellers are not EOM and were bought from different suppliers last year. I'm on my last one now and dreading starting the engine tomorrow am. I glued up a couple of separated ones 2 days ago using 5200 but I'm not really optimistic on that front. I will stop in Marsh Harbour tomorrow and see if I can find an EOM impeller. I must say thank you everyone that took the time to reply. This is a very supportive forum.

[Compass790]

If you wish to try glueing I'd go with superglue ( cyonacrylate ) maybe not right spelling, close enuff, but it's likely a clearance problem. They use a form of that to glue o-rings. The only way to do it would be to have the rubber on the brass boss & shove the glue nozzle down between them.You could try putting silicone on the gasket & letting it dry to increase clearance slightly. That clearance is critical, too much & it wont pump, too little & impellers don't last.
Maybe 5200 mite work too. Let us know what happens

[billgewater]

I purchased a Yanmar 1GM new back in the 80's. The impeller and pump assembly gave problems from the beginning and the price for Yanmar parts was just frightening. I took the gear box off and built a lay shaft off the flywheel to use the engine as a gen set etc. (My boat is 16 m) The engine now runs a couple of compressors (freezer, air con, diving) and I have hung a 3 KVA 240 VAC alternator under the engine. Obviously not all run at once. I installed a dedicated belt driven Fynspry (NZ) half inch sea water pump running off the lay shaft. This water flow passes through the condensers and the engine. As the engine has not got any automatic speed adjustment I have to manually set the throttle for any particular use. This has been a great success ever since. Still has the original impeller. My suggestion is that if you want to use the engine for anything else other than propulsion, then possibly mounting a belt driven standard pump off the front (needs an added pulley) may be worth considering.
Another thought is that as these engines are direct salt water cooled, then possibly it has gunk in the cooling galleries or the exhaust water injection creating problems for the dinky little built in pump.

[Boston Blackie]

I have replaced the inaccessable OEM raw water pump on our Yanmar 3JH2-TE with a beautiful bronze F6B-9 Johnson crankshaft driven raw water impeller pump. Impellers are less than half the cost of the Yanmar pump and simple to service with an Impuller tool. The pump was $160 but did need to have some holes added to the glange to stay balanced and mount to the Seafrost sheave. Built an aluminum torque bracket to accept the 5/16 pump torque bolt.

[01kiwijohn]

Originally Posted by mattyc

On the Yanmar 1GM10 the water pump is gear driven,not belt driven.

Maybe it is, but this does not negate the need for good, standard workshop practices. still should be able to turn it by hand, before firing it up. Fellas like me make good money from fellas like you.

[canyonbat]

After reading all of the great replies, I am wondering if you could have a bad bearing in the pump causing the shaft to fall out of alignment. Certainly a mystery. Too bad you are so far away, I replaced the pump on ours a couple of months ago and rebuilt the old one for a spare. I also kept most of the old impellers.

[01kiwijohn]

Originally Posted by canyonbat

After reading all of the great replies, I am wondering if you could have a bad bearing in the pump causing the shaft to fall out of alignment. Certainly a mystery. Too bad you are so far away, I replaced the pump on ours a couple of months ago and rebuilt the old one for a spare. I also kept most of the old impellers.

ANy noticeable play would indicate the bearings need replacement. Usually, bearing wear is evident on belt drive pumps after the pump has been run for a period with the belt too tight. This wear will also be evident on the inside of the cover plate. It will be heavily worn on one side of its circular path.
FYI, I've found these to be mostly Johnson pumps so the parts can be sourced from local vendors. The bearings and seal are also available from industrial suppliers and you can expect to pay about $20 for a set to fit a 3GM30 .

[mattyc]

Originally Posted by 01kiwijohn

ANy noticeable play would indicate the bearings need replacement. Usually, bearing wear is evident on belt drive pumps after the pump has been run for a period with the belt too tight. This wear will also be evident on the inside of the cover plate. It will be heavily worn on one side of its circular path.
FYI, I've found these to be mostly Johnson pumps so the parts can be sourced from local vendors. The bearings and seal are also available from industrial suppliers and you can expect to pay about $20 for a set to fit a 3GM30 .

New bearings and seals last fall.

[Talbot]

I was going to recommend fitting speedseals, as these can make a dramatic difference in impellor life. However I went to their website to get a link and discovered that they have gone out of business. Glad I have mine!

[Teknishn]

I've experienced this with my 1GM as well. In one case, the thermostat had gone bad. The engine overheated, also causing heat build up at the pump due to friction and no water flow (heating the rubber of the impeller and breaking it down). In the second case, I found that I didn't have sufficient raw water in-flow due to sea growth fouling the through-hull. Still had some water flowing through the engine, but not enough to keep the engine cool enough and causing the impeller to run dry (and causing over heating of the impeller). I typically get between 300-500 hours of operation using non-OEM impellers before replacement is needed.

Oh, and trying to glue them back together? Doesn't work for more than a couple of hours no matter what type of adhesive one uses (Epoxy, Super Glue, 5200, Perma-Tex, etc....been there, done that). Hope this helps.

[sailorladd]

You can also turn the cover plate around and use that smooth (new) surface as well, and don't forget to lubricate the impeller with a water proof grease like anhydrous lanolin (sheep's fat) which as a lot of used on a boat (all your mooring, ground tackle and rigging shackles threaded pin had be lubricated with this natural product even shackles on moorings underwater for years are easy to undo with this on it...

[Ringmaster]

Here's an idea. Just buy a new waterpump.

[drcat]

This has to be one of the extreme examples of poor raw water pump designs, especially with a seawater cooled diesel. Yes you can try more impellers, or lubricants but that has not worked yet.
Given your location can you find a 12v waterpump that can be turned on to pump seawater thru engine when running? Longer term I'd look to convert engine to closed loop cooling if possible. My preference would be two 12v magnetic drive waterpumps (one for circulating engine coolant, other for pumping seawater) plus a water to water heat exchanger. As an example , Ebay has mag drive water pumps suitable for your flow needs for less than $50 each and also a water to water heat exchanger meeting your needs for about $100. Mag drive pumps can run for 10K hours but are not self-priming so seawater one must be below water level.

[rla]

I really think you have a blockage problem somewhere in the system.
As it happens a boat I motored back from Eastern Germany last May has just been having some pre season work and despite the impellor having no damage or wear we found 7 impellor blades in the thermostat gallery !!
THere was no overheating on the trip or during last summer and we werre most surprised at how restricted the flow should have been but didn't show.
Have a good look through the whole system, I think you will find something !!

[revere]

1.Definitely only use Yanmar impellers. The few pennies you save buying knockoffs aren't worth it for such a critical part of your engine.
2. Check the wear on your pump housing. I had the same problem with impellers not priming and running dry due to a worn internal pump housing. I changed the pump and problem went away.
3.Lube the impeller with glycerin. This will help with keeping the impeller from burning up before it is primed
4. There is a upgrade kit that has a turning disc on the inside face of the plate. It's supposed to enable the pump to run dry. The Coast Guard has standardized on these upgrade pump kits.