Yanmar 1GM10 - Impeller problem

[mattyc]

Originally Posted by Captndave1

When you assemble the new impeller, coat the inside of the pump housing and the impeller blades with a thin coat of silicone grease, this will solve your problem

Did that.

[mattyc]

Originally Posted by sailm8

I think your impellers are missing the flat spot on the inside metal collar. Can't really see it from your picture. Also several years ago there was a bad batch of OEM impellers that were defective. I would have thought they were all gone by now.

They have the flat spot on the metal collar - hard to tell from pic. My spare impellers are not OEM and were bought last fall.

[canyonbat]

We have that engine on our Seaward and have went through a half dozen impellers over the past ten years. None actually failed, I just change them out with Yanmar replacements every other year. The only thing I can think of, besides a badly corroded pump or wrong impeller size would be installing them with the vanes oriented to the wrong rotation or not all of the vanes in the same direction. I use the zip tie trick to keep the vanes in place until I get the impeller started on the shaft. I know this sounds obvious but I have often found myself scratching my head on which way they go. Good luck solving the problem.

[AA3JY]

Originally Posted by canyonbat

The only thing I can think of, besides a badly corroded pump or wrong impeller size would be installing them with the vanes oriented to the wrong rotation or not all of the vanes in the same direction. I use the zip tie trick to keep the vanes in place until I get the impeller started on the shaft. I know this sounds obvious but I have often found myself scratching my head on which way they go.

No need too..they (vanes) self align once pump turns..

But if one needs to know it is counter rotation when facing from front of pump.

[Mack Boring Diesel Tech school]

[mattyc]

Originally Posted by canyonbat

We have that engine on our Seaward and have went through a half dozen impellers over the past ten years. None actually failed, I just change them out with Yanmar replacements every other year. The only thing I can think of, besides a badly corroded pump or wrong impeller size would be installing them with the vanes oriented to the wrong rotation or not all of the vanes in the same direction. I use the zip tie trick to keep the vanes in place until I get the impeller started on the shaft. I know this sounds obvious but I have often found myself scratching my head on which way they go. Good luck solving the problem.

I use the same method including the head scratching. It certainly is a mystery.

[morribabes]

I had similar difficulties with my 1GM10. I developed a theory that the problem was that when I stopped the engine with the pull handle the engine would bounce backwards when the piston came up on compression and reverse the direction the vanes on the impeller were pointing. They didn't like doing that and resisted to the point where the bond between the rubber and the brass centre was destroyed. I found stopping the engine with the decompressor lever on the cylinder head meant that the engine did not rotate backwards. It might have solved the problem as the last impeller lasted well over a year and was still going strong when I sold the boat.

[mattyc]

Originally Posted by morribabes

I had similar difficulties with my 1GM10. I developed a theory that the problem was that when I stopped the engine with the pull handle the engine would bounce backwards when the piston came up on compression and reverse the direction the vanes on the impeller were pointing. They didn't like doing that and resisted to the point where the bond between the rubber and the brass centre was destroyed. I found stopping the engine with the decompressor lever on the cylinder head meant that the engine did not rotate backwards. It might have solved the problem as the last impeller lasted well over a year and was still going strong when I sold the boat.

Well , that's an interesting theory. I'm going to take the impeller cover off and see how the vanes are aligned. Never had this problem before though. ...

[01kiwijohn]

If it's ripping the drive key/pin out, there's obviously too much frictional resistance for it to happen in such a short time.
Lube the hell out of the new impeller, before and during assembly, with silicone grease (Any plumbing dept. at a hardware store sells this) Once assembled, you should be able to turn the pump by grasping the drive sheave by hand, using only your fingers, without great difficulty.
Do not overtighten the drive belt as it will put too much load on the bearings, which are quite close together, causing the shaft to run out of alignment and you'll see the uneven wear pattern on the inside of the pump cover plate.

[mattyc]

Originally Posted by 01kiwijohn

If it's ripping the drive key/pin out, there's obviously too much frictional resistance for it to happen in such a short time.
Lube the hell out of the new impeller, before and during assembly, with silicone grease (Any plumbing dept. at a hardware store sells this) Once assembled, you should be able to turn the pump by grasping the drive sheave by hand, using only your fingers, without great difficulty.
Do not overtighten the drive belt as it will put too much load on the bearings, which are quite close together, causing the shaft to run out of alignment and you'll see the uneven wear pattern on the inside of the pump cover plate.

On the Yanmar 1GM10 the water pump is gear driven,not belt driven. To clear up one point, each one has run a couple of hours ( one went about 20 hours) but when they fail it just after starting the engine again. Start the engine, impeller separates from metal core, engines overheats and warning buzzer sounds.

[mattyc]

Originally Posted by 01kiwijohn

If it's ripping the drive key/pin out, there's obviously too much frictional resistance for it to happen in such a short time.
Lube the hell out of the new impeller, before and during assembly, with silicone grease (Any plumbing dept. at a hardware store sells this) Once assembled, you should be able to turn the pump by grasping the drive sheave by hand, using only your fingers, without great difficulty.
Do not overtighten the drive belt as it will put too much load on the bearings, which are quite close together, causing the shaft to run out of alignment and you'll see the uneven wear pattern on the inside of the pump cover plate.

Drive key/pin out? On these impellers there is only a flat on the metal core that fits the flat on the shaft. Is this what you mean by a drive key/pin out?

[AA3JY]

http://www.cruisersforum.com/forums/...mps-89997.html

[Zoidislander]

+ 1 for the Globe impellers. I have been using them for years, and have never had a failure.

[mattyc]

Originally Posted by AA3JY

http://www.cruisersforum.com/forums/...mps-89997.html

Thx. I'll read this thread.

[mattyc]

Originally Posted by 01kiwijohn

If it's ripping the drive key/pin out, there's obviously too much frictional resistance for it to happen in such a short time.
Lube the hell out of the new impeller, before and during assembly, with silicone grease (Any plumbing dept. at a hardware store sells this) Once assembled, you should be able to turn the pump by grasping the drive sheave by hand, using only your fingers, without great difficulty.
Do not overtighten the drive belt as it will put too much load on the bearings, which are quite close together, causing the shaft to run out of alignment and you'll see the uneven wear pattern on the inside of the pump cover plate.

I have both Super Lube and Dielectric Grease on board. Are both suitable for lubing the impeller?

[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?