Tips on raw water pump install?

[Dougcole]

I've found the easiest way to change the impellers on my Yanmar 4LHA-stps is to pull the pump. I can do it super quick and easy on the starboard motor, but the port side, which is much harder to reach, is more difficult.


Sometimes it goes quick, but sometimes I run into a particular problem and wonder if anyone has suggestions.


What happens is that the splined shaft turns a tiny bit when I put on the new impeller and as a result it doesn't line up right when I try to put it back in. The four studs that hold the pump onto the motor limit how much I can twist the pump. Also, getting the angle right so the pump slides straight in is challenging when I can't really see it.


Maybe switch the studs out for bolts?


Thanks.

 

[Comodave]

My starboard impeller is really tough to change. I bought a tool from impellertool.com which really helps with changing it. Don’t know if it would help you or not but it makes it easy to get the new impeller into the pump.

 

[FoxtrotCharlie]

Recently had to change the impeller on our starboard FL135 - tight space. Local mechanic was a big help - told me to coat it with dishwashing liquid soap to help installing - went in smoothly - washes off harmlessly.

 

[O C Diver]

When you pull the pump, put a mark on the housing to indicate spline peak. A scratch tool would work. After reassembling the pump wet the impeller and rotate the shaft till the mark lines up.

Ted

 

[Comodave]

With the impeller tool I referred to above you can easily turn the new impeller to get it lined up with the spline. It keeps the impeller vanes compressed as you slide the tool into the pump and then hold the impeller and pull the tool out.

 

[Dougcole]

Is there a peak on the shaft? I didn't know that.



I see what you are saying about lining it up. The gears are pretty fine, so it needs to be dead on.


If there is not a peak, I guess I could just put a scratch on the end of the shaft and on the housing?

 

[O C Diver]

Is there a peak on the shaft? I didn't know that.



I see what you are saying about lining it up. The gears are pretty fine, so it needs to be dead on.


If there is not a peak, I guess I could just put a scratch on the end of the shaft and on the housing?

Don't know if there's a peak, my point is that it would be pretty simple to make alignment marks on the shaft and housing each time you pull the pump. Maybe mark the shaft once and the housing each time you pull the pump.

Ted

 

[Dougcole]

Don't know if there's a peak, my point is that it would be pretty simple to make alignment marks on the shaft and housing each time you pull the pump. Maybe mark the shaft once and the housing each time you pull the pump.

Ted

I see what you mean. Thanks Ted.


Do y'all see any value is taking out the studs to allow more wiggle room? Or maybe all but one of them?

 

[Comodave]

On mine I couldn’t get down far enough to see any marks. I am pretty much changing it by feel.

 

[syjos]

If you don't have an impeller installation tool mentioned by comodave you can use a hose clamp around the impeller to bend them in the direction of rotation so you only have to deal with the shaft.

Once you compress the impeller, you can spin it around until it goes in without the rubber impeller blades hindering insertion.

A pipe or tube could also be used to compress the blades, but you have to find one of the correct diameter.

The video at impellertool.com is informative.

 

[Comodave]

The impeller tool makes it possible to change the impeller without removing the pump. The marina where I bought the boat maintained it for 15 years. I asked them how they ever changed the impeller. They said the first step was to draw straws to see who had to do it... Then they said they usually had to remove the pump which is a bugger. With the impeller tool and a Jabsco impeller puller I can now do it in less than 20 minutes. It really isn’t too bad to do now. And I can only see parts of the pump by looking in between the hoses and pipes.

 

[Dougcole]

If you don't have an impeller installation tool mentioned by comodave you can use a hose clamp around the impeller to bend them in the direction of rotation so you only have to deal with the shaft.

Once you compress the impeller, you can spin it around until it goes in without the rubber impeller blades hindering insertion.

A pipe or tube could also be used to compress the blades, but you have to find one of the correct diameter.

The video at impellertool.com is informative.

Thank you, but I don't have any issues putting the impeller back in the pump or getting it out of the pump after it is off.



The issue I run into about 40% of the time, is getting the pump shaft back into the motor on the port side which is hard to reach and see.



Getting the impeller out of the pump without taking the pump off of the engine is impossible, there isn't room to get any sort of puller into the pump. I actually don't think there is enough clearance to get the impeller out past the pump even if you could get it out.


Pulling the little bolts to get the pump cover off in a space that you can't see would be a nightmare. The right way to do it is to pull the pump.



But, like I said, getting the pump back in on that side can sometimes be difficult.

 

[Comodave]

Ok, I misunderstood what the issue is. Sounds like you have the wrong engine...

 

[O C Diver]

I see what you mean. Thanks Ted.


Do y'all see any value is taking out the studs to allow more wiggle room? Or maybe all but one of them?

On my John Deere, there are bolts instead of studs. Without studs, I insert the spline, and then turn the pump body unit the bolt holes line up. I would assume it would be much easier that way, but don't know if there's any reason not to replace the studs with bolts.

Ted

 

[Baker]

For those mentioning impeller tools, it is pretty much impossibe to change the impeller with the pump on the engine. I used to own one....it was a big time PIA to change the impeller.

 

[Dougcole]

For those mentioning impeller tools, it is pretty much impossibe to change the impeller with the pump on the engine. I used to own one....it was a big time PIA to change the impeller.

This is true. Great little motors, I absolutely love mine, but like everything else on boats, not perfect.


Good news is that the pumps are easy to pull, four nuts and the outlet hose and they are off. I have a lot of length to work with on my inlet hoses, so I just leave them connected to the pump. Impellers are easy to change with the pump off.


Getting the stb pump back on is easy as well, it's just the port side that can be a bear.

 

[Bacchus]

For those mentioning impeller tools, it is pretty much impossibe to change the impeller with the pump on the engine. I used to own one....it was a big time PIA to change the impeller.

This is true. Great little motors, I absolutely love mine, but like everything else on boats, not perfect.


Good news is that the pumps are easy to pull, four nuts and the outlet hose and they are off. I have a lot of length to work with on my inlet hoses, so I just leave them connected to the pump. Impellers are easy to change with the pump off.


Getting the stb pump back on is easy as well, it's just the port side that can be a bear.

I'm assuming you have the same Yanmar 6LYA as I do. If so I disagree if you have the right tools.
My pump is a Johnson F75B-9 and impeller is a 09-821-BT - The "T" is threaded on the ID and fairly easy to remove with the right puller.
I was in a rush this spring and had my yard change mine befor departing on a summer cruise. The yard actually borrowed my puller as theirs didn't work as well. I did buy a couple longer metric bolts to permit pulling it out of the housing further.
A piston ring compressor works well for reinstalling the new impeller.

The puller is a Johnson Pump 09-821BT Impeller Puller
SKU: JP-09-47163-01

 

[Baker]

I'm assuming you have the same Yanmar 6LYA as I do. If so I disagree if you have the right tools.

4LHA-STP. Completely different animal. There is absolutely no room for a puller on these engines. Literally not possible.

Strangely the 4LH(no “A”)-STE has a completely different raw water pump setup. Basically the same engine but the accessories are different.

 

[rgano]

I've found the easiest way to change the impellers on my Yanmar 4LHA-stps is to pull the pump. I can do it super quick and easy on the starboard motor, but the port side, which is much harder to reach, is more difficult.


Sometimes it goes quick, but sometimes I run into a particular problem and wonder if anyone has suggestions.


What happens is that the splined shaft turns a tiny bit when I put on the new impeller and as a result it doesn't line up right when I try to put it back in. The four studs that hold the pump onto the motor limit how much I can twist the pump. Also, getting the angle right so the pump slides straight in is challenging when I can't really see it.


Maybe switch the studs out for bolts?


Thanks.

My only seawater pump on my Yanmar 6PLA-STD is also difficult to get to. I have developed the method of placing two throwable cushion floats on the top of the motor and lie on them facing forward. I am left handed; so using a wrench with that hand out of sight is not an issue. My pump's impeller can only be changed by removing the pump from the engine, and the two studs holding it to the engine made life miserable when it came time to get the pump and engine gears aligned. Sooo I removed the studs and now use bolts instead. Way faster.

 

[Dougcole]

My only seawater pump on my Yanmar 6PLA-STD is also difficult to get to. I have developed the method of placing two throwable cushion floats on the top of the motor and lie on them facing forward. I am left handed; so using a wrench with that hand out of sight is not an issue. My pump's impeller can only be changed by removing the pump from the engine, and the two studs holding it to the engine made life miserable when it came time to get the pump and engine gears aligned. Sooo I removed the studs and now use bolts instead. Way faster.

Thanks, that's pretty much my exact problem. I think I'm going to try that. Was it hard to get the studs out?

 

[rgano]

I used vicegrips to get the studs out. Do not overtighten the new bolts - the metal there is not real thick.