Does anyone know if there is a way to reverse the raw water pump on a Yanmar 2GMF? I don't like the idea of having to remove my water pump every fall in order to remove the impeller for winter storage. On other pumps I have had with the cover plate facing out I installed a special cover with three screws with knurled knobs which made change out real quick. I'd be interested to hear from anyone who has figured out a workable solution to this problem. Reg
Is there a way to reverse the raw water pump on a Yanmar 2GMF?
- Thread starter Reg M
- Start date
IF you remove the impeller after its been used, I believe it will "dry out". I'm not sure if you really want to soak it in some special "gooh" to preserve it. Why are you fixated on it?
I've had impellers last three or four years on our generator (with winterizing in engine rated winterizing solution each winter). I've also had impellers that "gave up", usually from something blocking the intake like grass or nettles. Our Yanmar main engine has had impellers that last for that long, but I usually have it replaced every couple of years, just because I use the engine a lot each summer on long cruises to and from Maine most years. I can tolerate replacing an generator impeller -- but if the impeller goes on the Yanmar it's not in a place that is easily acessed when the engine is hot. Plus, if I'm motoring, it's not because I just want to turn the engine off and become a tangle of @sshole and elbows trying to get the "plant" going again ;^))).
We have the Speedseals which you describe. http://www.speedseal.com/speedseal.html
They are great (unless you drop the screw in the engine bilge or somewhere else. :^) I never would have made it as a neurosurgeon :^)))).
I've had impellers last three or four years on our generator (with winterizing in engine rated winterizing solution each winter). I've also had impellers that "gave up", usually from something blocking the intake like grass or nettles. Our Yanmar main engine has had impellers that last for that long, but I usually have it replaced every couple of years, just because I use the engine a lot each summer on long cruises to and from Maine most years. I can tolerate replacing an generator impeller -- but if the impeller goes on the Yanmar it's not in a place that is easily acessed when the engine is hot. Plus, if I'm motoring, it's not because I just want to turn the engine off and become a tangle of @sshole and elbows trying to get the "plant" going again ;^))).
We have the Speedseals which you describe. http://www.speedseal.com/speedseal.html
They are great (unless you drop the screw in the engine bilge or somewhere else. :^) I never would have made it as a neurosurgeon :^)))).
Speedseal is great if the pump is mounted as shown in the photo, BUT the OP and I have Yanmar ( mine is a 3GM30F) with the pump mounted with the cover facing the engine - need to completely remove it / belt, screws, etc to get to the cover.
The Yanmar's themselves aren't the issue, it's how the builder has to "cram" all the stuff into an overly tight compartment. On our Yanmar 4JH2 - DTBE, we have some hoses and electrical harness wiring that makes the easy access to the Speedseal more problematic. That's why I just change the impeller every year of two, regardless.
We put 200 or more hours on the engine every year. I've NEVER had the Yanmar's impeller fail. I've had the Westerbeke generator's impeller self-destruct sometimes once or twice in a day with grass and nettles. Most of the time, they last multiple seasons without incident. When we are in the Chesapeake in July or early September and using the generator in "saltier" water, there are more nettles. Sometimes the nettles just clog up the stainer and the impellers survive. In Newport/Marthas Vineyard and some similar places the Eel Grass seems to love to clog things up similarly. If you notice the change in pitch of the generator noise, you can cut the motor before it overheats; however, if you run the generator "dry", I've found that the impeller is often toast. Then, you might lose a vane on the impeller, it might work for a while, but you're risking clocking your heat exchanger up.
We put 200 or more hours on the engine every year. I've NEVER had the Yanmar's impeller fail. I've had the Westerbeke generator's impeller self-destruct sometimes once or twice in a day with grass and nettles. Most of the time, they last multiple seasons without incident. When we are in the Chesapeake in July or early September and using the generator in "saltier" water, there are more nettles. Sometimes the nettles just clog up the stainer and the impellers survive. In Newport/Marthas Vineyard and some similar places the Eel Grass seems to love to clog things up similarly. If you notice the change in pitch of the generator noise, you can cut the motor before it overheats; however, if you run the generator "dry", I've found that the impeller is often toast. Then, you might lose a vane on the impeller, it might work for a while, but you're risking clocking your heat exchanger up.
Unless you're running the engine for a while where grass or nettles or whatever can clog things up.Reg M (and others), I don't think that an auxiliary running in open water will need impeller changes all that often. That woudl especially be the case with people run the engines regularly during the season. If you let an engine sit for a couple of years unused, then its a different story.
When I was living in southern waters and during my cruising years when the boat was in use year around I just changed impellers once a year but up here in the frozen north we haul our boats the first week of Oct and launch the first week of Jun - that's 8 months every year the impeller is not moving and 2 or 3 of the vanes are bent over the whole time. If you remove an impeller from a pump that has been idle that long you will see 2 or 3 of the vanes do not come back to their original shape and chances are very high those vanes will fail during the second season and of course it will always do so at the worst possible time. I learned this the hard way on my second boat (the 1st had an outboard) As for the winterizing, I do pump plumbers antifreeze through the engine and after doing so I remove the pump and take out the impeller. I respectfully disagree with your theory that taking a used impeller out of the pump for the winter will cause it to fail. The impeller is rubber and was exposed to the air before use, I have never heard of water causing rubber to rot but then again, even at my age I learn something new every other day. Winterizing is not the only reason I want to change the pump configuration, in the event of an impeller failure while underway, especially in tight conditions, if you have a speedseal and the cover plate is facing out, you can change the impeller in very quick time. I once had one go and my temp alarm went off during high winds, not far from a lee shore in St George's Harbour, Bermuda. Having the speedseal I had it change out in less than 2 minutes. The problem with the Yanmar pump, as stated by someone else above, is that the cover plate faces the engine and you have to remove the belts, then remove the pump in order to change the impeller I'm thinking there has to be a similar pump that rotates opposite to the one I have.IF you remove the impeller after its been used, I believe it will "dry out". I'm not sure if you really want to soak it in some special "gooh" to preserve it. Why are you fixated on it?
I've had impellers last three or four years on our generator (with winterizing in engine rated winterizing solution each winter). I've also had impellers that "gave up", usually from something blocking the intake like grass or nettles. Our Yanmar main engine has had impellers that last for that long, but I usually have it replaced every couple of years, just because I use the engine a lot each summer on long cruises to and from Maine most years. I can tolerate replacing an generator impeller -- but if the impeller goes on the Yanmar it's not in a place that is easily acessed when the engine is hot. Plus, if I'm motoring, it's not because I just want to turn the engine off and become a tangle of @sshole and elbows trying to get the "plant" going again ;^))).
We have the Speedseals which you describe. http://www.speedseal.com/speedseal.html
They are great (unless you drop the screw in the engine bilge or somewhere else. :^) I never would have made it as a neurosurgeon :^)))).
Last edited:
Reg M .. Found it: https://forums.sailboatowners.com/i...new-project-that-might-be-of-interest.148014/
I knew I'd seen it here on the site, couldn't remember ..
I knew I'd seen it here on the site, couldn't remember ..
You don't change out the other rubber parts why single out the impeller?
don't use RV anti on rubber. test have shown that emersion for long periods in rv anti make the impeller rubber brittle
take off the inlet and outlet hoses, crank the engine a few turns and drain the rest of the raw water system. Air does not freeze and small amounts of water that are not trapped in closed spaces will not cause a problem.
I check my impeller when I get an indication of low water flow. This year was the first time I had to replace the impeller and that was 8 years. One vain had a missing outer end
Really guys the stuff is made of the same rubber as car tires. You don't have to take it out every winter, just remove the water and relax
don't use RV anti on rubber. test have shown that emersion for long periods in rv anti make the impeller rubber brittle
take off the inlet and outlet hoses, crank the engine a few turns and drain the rest of the raw water system. Air does not freeze and small amounts of water that are not trapped in closed spaces will not cause a problem.
I check my impeller when I get an indication of low water flow. This year was the first time I had to replace the impeller and that was 8 years. One vain had a missing outer end
Really guys the stuff is made of the same rubber as car tires. You don't have to take it out every winter, just remove the water and relax
The cold hard voice of reason.
Original Yanmar impellers are as tough as anything you'll find on the engine. I check mine every few years and it's now six years old. Looks new. Based on approx. 100 hours/year.
It's the number of starts that's more important than the number of hours, I think. The start with "dry" conditions is tough.
The concern is the long term disuse sterling the compressed vanes.
I agree that for most of us, absent really prolonged disuse, it's not that dramatic a concern.
But if you have some other incident (like hauling and drying out the compressed impeller, then other issues might come to play.
If you've ever had a high temp alarm in a tight situation where you have to concern yourself with either losing the boat or your engine, then you will kick yourself for not paying attention to either slight changes in flow or increases in operating temps warnings that you might have acted on. Of course, an idiot light warning gives you no notice. If you lose water flow at 2500 rpm with a warmed up engine, you have little time to shut down.
The concern is the long term disuse sterling the compressed vanes.
I agree that for most of us, absent really prolonged disuse, it's not that dramatic a concern.
But if you have some other incident (like hauling and drying out the compressed impeller, then other issues might come to play.
If you've ever had a high temp alarm in a tight situation where you have to concern yourself with either losing the boat or your engine, then you will kick yourself for not paying attention to either slight changes in flow or increases in operating temps warnings that you might have acted on. Of course, an idiot light warning gives you no notice. If you lose water flow at 2500 rpm with a warmed up engine, you have little time to shut down.
If the impeller is above the water line...then, depending on time involved and the "seal"...water "seeks it level"?
Or if you have the boat hauled, Or in very rough seaways.
Or if the supply is impeded while the pump continues to "draw" (blockage, or you shut the seacock, etc.)
P.S. - if that's your engine, Ralph, it looks SO VERY CLEAN :^))) and ORGANIZED!!
In the normal course of intermittent use, it's usually not an issue.
Or if you have the boat hauled, Or in very rough seaways.
Or if the supply is impeded while the pump continues to "draw" (blockage, or you shut the seacock, etc.)
P.S. - if that's your engine, Ralph, it looks SO VERY CLEAN :^))) and ORGANIZED!!
In the normal course of intermittent use, it's usually not an issue.