I changed the impeller this past weekend in my Yanmar 3GMF. When I took the old one out it had a blade completely missing. Do I need to try to track down the blade thru the hoses, heat exchanger, exhaust, etc? My engine has run fine since last winter when I changed it last. Thanks, Joe Mullee
Impeller Question - Blade Torn Off
- Thread starter Joe Mullee
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why take the chance?
It's liable to overheat at the worst possible time, or it may be fine but why tempt fate? It's probably in the heat exchanger and should be easy to find and remove.
It's liable to overheat at the worst possible time, or it may be fine but why tempt fate? It's probably in the heat exchanger and should be easy to find and remove.
Don't think that your problem is uncommon
Joe: I do not think that this problem is uncommon. Most of the time these blades start to crumble and they end up passing thru the system. If you really think you should check, then I would remove the from cover on the heat exchanger. If you do not find it there, you will probably not find it. If it has passed the pump hose, it was not very big.
Joe: I do not think that this problem is uncommon. Most of the time these blades start to crumble and they end up passing thru the system. If you really think you should check, then I would remove the from cover on the heat exchanger. If you do not find it there, you will probably not find it. If it has passed the pump hose, it was not very big.
When I showed
a small handful of black rubber pieces to a young female friend , she said, your impeller! Did you get all the pieces? Reassemble the impeller as best you can and se how much you have and then look at the discharge hole in the pump to see how large a piece could get through.
a small handful of black rubber pieces to a young female friend , she said, your impeller! Did you get all the pieces? Reassemble the impeller as best you can and se how much you have and then look at the discharge hole in the pump to see how large a piece could get through.
heat exchanger
When I pulled mine it looked an entire impeller was there in little tiny bits. All the salt water scale wasn't helping either, but a trip to the radiator shop fixed that.
When I pulled mine it looked an entire impeller was there in little tiny bits. All the salt water scale wasn't helping either, but a trip to the radiator shop fixed that.
Check the output flow with a new impeller in
If the output flow at the exhaust opening at the stern is between 3-4 gallons per minute with the engine running at about 3000 rpm then the circuit is clear and the impeller part has probably passed through. If not to that level of output flow (check your engine manual for your particular model for the correct flow at specified rpm) then you need to find and remove the piece that is partly blocking the circuit in the heat exchanger or in the internals of the exhaust manifold, etc.
If the output flow at the exhaust opening at the stern is between 3-4 gallons per minute with the engine running at about 3000 rpm then the circuit is clear and the impeller part has probably passed through. If not to that level of output flow (check your engine manual for your particular model for the correct flow at specified rpm) then you need to find and remove the piece that is partly blocking the circuit in the heat exchanger or in the internals of the exhaust manifold, etc.
smallest hole in the whole system is the exchanger
so remove both ends of the exchanger, and you will see a bunch of tubes all the way through to the other end. Shine a light from one end, and look through from the other end to see if all the tubes are clear. Or blow through the tubes. Make sure when you remove the gasket, mark it so you will be able to put it back together correctly.
so remove both ends of the exchanger, and you will see a bunch of tubes all the way through to the other end. Shine a light from one end, and look through from the other end to see if all the tubes are clear. Or blow through the tubes. Make sure when you remove the gasket, mark it so you will be able to put it back together correctly.
Those are all good ideas. Now here's the easy way
to do the same thing. Symptom; missing impeller blade. Remove the small hose to the heat exchanger. Blow, blow, blow. (Good one Franklin!
) If nothing, remove the front cover of the heat exchanger. It should be there. If not, don't worry about it. Put it back together and go sailing. But take that cover off. One impeller blade will get trapped here and significantly reduce flow. Check out the cover O-ring. See how it compartmentalizes the flow so as to switch it back and forth three times? That's so as to gain maximum heat removal with available seawater. It's important to check here. Now if you also find significant scale in the tubes, DO NOT FRET! ) sorry, too much fun) Go to your local Home Depot (or any hardware store) and pick up one of those really long drill bits used by electricians for making pilot holes. You want a 1/4 inch bit. Chuck it up to your drill. Start it in each heat exchanger hole by turning the chuck by hand until it's lined up in the tube. Then apply power. It's best to have a variable speed drill. Then just push it in to the rear of the exchanger. The bit stops at the back cover. Push no more. Do the next tube and so on. No need to blow out the crud. It'll flush out when you reassemble and start the engine. That's it. Put the cover back on. The O-ring is probably reusable. It's really a rubber gasket. It took a lot of typing to describe a really simple job. Once you see how easy it is, It'll be on your list of regular tasks. P.S. ROSS! I think there's a rule against arousing Posts!
to do the same thing. Symptom; missing impeller blade. Remove the small hose to the heat exchanger. Blow, blow, blow. (Good one Franklin!
) If nothing, remove the front cover of the heat exchanger. It should be there. If not, don't worry about it. Put it back together and go sailing. But take that cover off. One impeller blade will get trapped here and significantly reduce flow. Check out the cover O-ring. See how it compartmentalizes the flow so as to switch it back and forth three times? That's so as to gain maximum heat removal with available seawater. It's important to check here. Now if you also find significant scale in the tubes, DO NOT FRET! ) sorry, too much fun) Go to your local Home Depot (or any hardware store) and pick up one of those really long drill bits used by electricians for making pilot holes. You want a 1/4 inch bit. Chuck it up to your drill. Start it in each heat exchanger hole by turning the chuck by hand until it's lined up in the tube. Then apply power. It's best to have a variable speed drill. Then just push it in to the rear of the exchanger. The bit stops at the back cover. Push no more. Do the next tube and so on. No need to blow out the crud. It'll flush out when you reassemble and start the engine. That's it. Put the cover back on. The O-ring is probably reusable. It's really a rubber gasket. It took a lot of typing to describe a really simple job. Once you see how easy it is, It'll be on your list of regular tasks. P.S. ROSS! I think there's a rule against arousing Posts!Impeller parts....
When I bought my H28.5 with the Yanmar 2GM20F I was shocked to find the impeller in the water pump nearly destroyed -- and I was facing a 100 mile trip to deliver the boat to my home port. All I had time for was to change the impeller and hope for the best. As it turned out, I had to motor a lot of the way home -- all the while worrying about where the pieces of the old impeller went. I kept a close eye on the engine temp and exhaust output and made it home nicely. Since that time, I've never been able to find any trace of the old impeller blades and assume they have long since gone to the bottom of the Chesapeake. What to do? If your engine has been run a lot since the blade went missing, you probably had the same experience that I did and probably have nothing more to do. I'd just keep an eye on the engine temp and exhaust, like we all do anyway.
When I bought my H28.5 with the Yanmar 2GM20F I was shocked to find the impeller in the water pump nearly destroyed -- and I was facing a 100 mile trip to deliver the boat to my home port. All I had time for was to change the impeller and hope for the best. As it turned out, I had to motor a lot of the way home -- all the while worrying about where the pieces of the old impeller went. I kept a close eye on the engine temp and exhaust output and made it home nicely. Since that time, I've never been able to find any trace of the old impeller blades and assume they have long since gone to the bottom of the Chesapeake. What to do? If your engine has been run a lot since the blade went missing, you probably had the same experience that I did and probably have nothing more to do. I'd just keep an eye on the engine temp and exhaust, like we all do anyway.
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