Hi Guys and Gals: Why in the world would a brand new Jabsco water impeller fail after two months of use? Yesterday after motoring for an hour and a half from Cadle Creek to Annapolis, the impeller gave out. I had just installed it in April. The grease cup was filled, etc. etc. And by the way, I wrote a post a few weeks back about smoke coming from the exhaust. I believe now that smoke was from my impeller beginning to degrade. I was not running my A-4 at top speed although I was going at a good clip. Did the failure of the impeller have something to do with the speed at which I was running the engine? Has anyone had a similar experience? Thanks Melody
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How old was it?
I'm the first to admit I'm a dunce when it comes to engines but I have seen several of Rob's impellors fail in a very short time apparently due to old age. The older they get, the more the rubber breaks down and the quicker they fail. And unfortunately, you never know how long they were sitting on the chandlery shelf before you bought it. It could also just have been a bad one. You might try replacing it again and seeing how long this one lasts. If it fails quickly, you definitely know something else is wrong! Hopefully someone else will shed some light!!
LaDonna
I'm the first to admit I'm a dunce when it comes to engines but I have seen several of Rob's impellors fail in a very short time apparently due to old age. The older they get, the more the rubber breaks down and the quicker they fail. And unfortunately, you never know how long they were sitting on the chandlery shelf before you bought it. It could also just have been a bad one. You might try replacing it again and seeing how long this one lasts. If it fails quickly, you definitely know something else is wrong! Hopefully someone else will shed some light!!
LaDonnaWho installed the impeller?
Melody: Don't know much about the A-4 but on the Yanmar, you need to install the impeller properly so it rotates in the proper direction. You need to have a spare on board so when you buy another one buy two. Make sure (if it makes a difference) that the arrow is going in the right direction. Not sure that this was the problem. There is always the possibility that the impeller was DEFECTIVE!
Melody: Don't know much about the A-4 but on the Yanmar, you need to install the impeller properly so it rotates in the proper direction. You need to have a spare on board so when you buy another one buy two. Make sure (if it makes a difference) that the arrow is going in the right direction. Not sure that this was the problem. There is always the possibility that the impeller was DEFECTIVE!
Impeller
Melody I had two fail, apparently Jabsco produced some with a bad adhesive that bonds the metal sleave to the rubber impeller. Check to see if the rubber impeller spins on the metal sleave. That's the indication of a faulty bond. I now carry a spare, and change it out every year, whether it needs it or not. Good luck Dan S/V Unruly Julie
Melody I had two fail, apparently Jabsco produced some with a bad adhesive that bonds the metal sleave to the rubber impeller. Check to see if the rubber impeller spins on the metal sleave. That's the indication of a faulty bond. I now carry a spare, and change it out every year, whether it needs it or not. Good luck Dan S/V Unruly Julie
running impellers dry
Melody, If you installed the impeller and a some time lapse before using it, the impeller could stick to the casing enough to damage it. This is from running it dry. When you change the impeller the pump is dry and if it does not pick up water right away it could get hot. Try a small amount of lubricant on the impeller when you change it. This will help lubricant it until it is primed and pumping. The grease does not stay on the impeller long so you don't have to worry about the grease breaking down the rubber. Is your intake clear. Is your intake filtered? Debris can ruin an impeller pretty quick. goodluck r.w.landau
Melody, If you installed the impeller and a some time lapse before using it, the impeller could stick to the casing enough to damage it. This is from running it dry. When you change the impeller the pump is dry and if it does not pick up water right away it could get hot. Try a small amount of lubricant on the impeller when you change it. This will help lubricant it until it is primed and pumping. The grease does not stay on the impeller long so you don't have to worry about the grease breaking down the rubber. Is your intake clear. Is your intake filtered? Debris can ruin an impeller pretty quick. goodluck r.w.landau
Melody, if the impeller housing is scored,
which can happen--it's not unusual...it'll "eat" impellers. I went through 2 before I thought to check the housing. It doesn't take much, just the slightest burr, to nick the ends of the vanes just enough to make the impeller stop impelling water...at which point the impeller fries, masking the real problem and causing you to keep trying to figure out what's frying your impeller instead of what's setting up the condition to fry it. Occasionally a bit of dirt or debris can destroy even a brand new impeller or an impeller can be defective (so always keep a spare aboard), but if an engine keeps frying impellers, look beyond that to what else can be happening that's damaging the impeller.
which can happen--it's not unusual...it'll "eat" impellers. I went through 2 before I thought to check the housing. It doesn't take much, just the slightest burr, to nick the ends of the vanes just enough to make the impeller stop impelling water...at which point the impeller fries, masking the real problem and causing you to keep trying to figure out what's frying your impeller instead of what's setting up the condition to fry it. Occasionally a bit of dirt or debris can destroy even a brand new impeller or an impeller can be defective (so always keep a spare aboard), but if an engine keeps frying impellers, look beyond that to what else can be happening that's damaging the impeller.
There is usually a reason
From my experience impellers disintegrate for one of three reasons. They run dry and get hot. They get torn apart by debris or a damaged housing. Or the blades stick to the housing and consequently rip apart when started up. In an engine that has set for an extended period of time the impellers can fuse themselves to the housing (especially if it is stored dry). Removing the cover and checking to be sure that the blades are free will prevent this. Lubricating the blades is a possibility, but the problem there is what to use that will not break down the rubber impellers. I've used Vaseline and it does not appear to damage the impeller blades. Running dry can be caused by a blockage at the intake scoop/strainer (by the way, it is a scoop, it should be facing forward) or a blockage at the intake filter (if you have one). If you don't have a filter, debris can be sucked up and travel into the housing and chew up the impeller. This same debris can also scar the housing and that can quickly chewed up a new impeller. Also trying to remove an old impeller with a screwdriver can damage the housing. Hope this helps. Good luck. John
From my experience impellers disintegrate for one of three reasons. They run dry and get hot. They get torn apart by debris or a damaged housing. Or the blades stick to the housing and consequently rip apart when started up. In an engine that has set for an extended period of time the impellers can fuse themselves to the housing (especially if it is stored dry). Removing the cover and checking to be sure that the blades are free will prevent this. Lubricating the blades is a possibility, but the problem there is what to use that will not break down the rubber impellers. I've used Vaseline and it does not appear to damage the impeller blades. Running dry can be caused by a blockage at the intake scoop/strainer (by the way, it is a scoop, it should be facing forward) or a blockage at the intake filter (if you have one). If you don't have a filter, debris can be sucked up and travel into the housing and chew up the impeller. This same debris can also scar the housing and that can quickly chewed up a new impeller. Also trying to remove an old impeller with a screwdriver can damage the housing. Hope this helps. Good luck. John
Temps Spiking recently, or over time?
A series of higher than normal temps, followed by an extended high temp condition could indicate the time of the break down of the impeller. If the cam shoe is worn, Moyer sells a new type out that helps increase waterflow through the engine. Also, are you using specific waterpump grease? I used the wrong type in my grease cup, and that shortens the life of the impeller. The grease should have a hard, waxy consistency, and a small tube should last you quite a while (years and years). Please report your findings back! p.s. - as for smoke, I don't think that would be caused by the impellar, as it would be encased by water the whole time, and also would have to pass through the entire water jacket before being remixed with the exhaust. Are the impellar paddles just broken, or is there evidence that they heated up and broke down into fine particles?
A series of higher than normal temps, followed by an extended high temp condition could indicate the time of the break down of the impeller. If the cam shoe is worn, Moyer sells a new type out that helps increase waterflow through the engine. Also, are you using specific waterpump grease? I used the wrong type in my grease cup, and that shortens the life of the impeller. The grease should have a hard, waxy consistency, and a small tube should last you quite a while (years and years). Please report your findings back! p.s. - as for smoke, I don't think that would be caused by the impellar, as it would be encased by water the whole time, and also would have to pass through the entire water jacket before being remixed with the exhaust. Are the impellar paddles just broken, or is there evidence that they heated up and broke down into fine particles?
Wasn't the Impeller After All . . .
Hey Guys and Gals: The brain trust on this forum is awesome. So many good people lending their expertise so that us newbies don't have to learn everything the hard way. Here's the scoop on what happened with me. It's a double whammy. Since, water was not coming out from the back of my boat, my marina neighbors said it was the impeller. In fact, there was some barnacle, muscle or other creature lodged in the exhaust blocking the flow of water out. But that's not all. I took out the impeller and it was in perfect condition. The previous owner of my boat comes over and removes the thermostat. It is totally mucked up. So the consensus is that the problem was a combination of a creature in my exhaust and a bad thermostat. (Apologies to the good people at Jabsco) I hope I can enjoy the rest of the boating season without incident. My math tells me that I've paid $500 in premiums to Allstate and consumed $700 worth of towing services. If they run the numbers on me, I'd be cancelled. Thanks to All, Melody
Hey Guys and Gals: The brain trust on this forum is awesome. So many good people lending their expertise so that us newbies don't have to learn everything the hard way. Here's the scoop on what happened with me. It's a double whammy. Since, water was not coming out from the back of my boat, my marina neighbors said it was the impeller. In fact, there was some barnacle, muscle or other creature lodged in the exhaust blocking the flow of water out. But that's not all. I took out the impeller and it was in perfect condition. The previous owner of my boat comes over and removes the thermostat. It is totally mucked up. So the consensus is that the problem was a combination of a creature in my exhaust and a bad thermostat. (Apologies to the good people at Jabsco) I hope I can enjoy the rest of the boating season without incident. My math tells me that I've paid $500 in premiums to Allstate and consumed $700 worth of towing services. If they run the numbers on me, I'd be cancelled. Thanks to All, Melody
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