How not to check the water impeller for damage

[baz]

I learned an important fact about inspecting the impeller at Fisherman's Terminal this past weekend. It's not sufficient to simply view the impeller outer surface and vane ends while it remains in the impeller housing with the pulley removed. Why... is this ? Well the visible end may indeed be without cracks but this does not mean the other inner side is the same.

One clue that a vane has been compromised but not visible from the outer end is if it appears to be bent over a little more than the others.

I will be replacing my Yanmar 4BY2-150 engine's raw water impeller sometime over the next month myself and will be curious to see its condition after some 270 engine hours and close to 4 years of use. I will be taking Herb's advice and ensure I have a towel stretched under the pulley as I remove the four pulley retaining bolts so they get caught if accidentally dropped. Thanks Herb. 🙂

 

[knotflying]

A good trick to prevent those bolts from dropping is to put a small piece of paper towel or table napkin on the end of the hex and then push it into the bolt. Do the same for installation and you should never drop it in the bilge. Sorry, can't help you if you drop the whole ratchet down there! :lol:

 

[trailertrawlerkismet]

I used Mike's paper towel trick when I changed my impeller two weeks ago, it works. I just can not imagine doing this project without it now, which makes me wonder how many other helpful tricks there are that can save time, money and frustration. Barry will you have help with the impeller project? It sure helped to have an extra set of hands and eyes when I did mine.

 

[baz]

Jim: Last year my engine mechanic (quite a few years younger than me, mind you) lay down on his belly and was able to remove the water pump's pulley belt and the pulley after removing the 4 bolts. It appeared to me to be quite easy with the tricky bit being removing the 4 bolts as he had to thread an extension between the pulley spokes to line up with the bolt heads.

I'm told pulling the old impeller out of its housing can be tricky also.

I note there's a large O ring and a paper gasket in the new impeller box/package and that the impeller is symmetric meaning it can be inserted either way... but that the vanes need to be bent in a particular way when installing. Where does the large O ring and paper gasket go ? The packaging also contains some impeller lubricant... is this for the impeller shaft or for the vane tips ? My guess is that the gasket and O ring are used between the housing and the pulley to obtain a decent seal.

I will certainly be using the paper towel trick as well as laying a secondary safety net with a towel stretched out below.

What was the 2nd person used for ? I intend to slip the pulley belt using a screwdriver shank as did my engine mechanic.

 

[knotflying]

Barry,

I did not have lubricant in my package nor a paper gasket. There is a grove on the pump housing that receives the large rubber o ring. You can hold this in place with a bit of Vaseline. I did put a little soap on my impeller to lube it up and turned it in the proper direction as I was pushing it in. I used the second person to work the belt on from inside the cabin access while I was outside turning the crankshaft.

Hope this helps,

Mike Rizzo

 

[baz]

Mike: What location was used to turn the crankshaft ? Was it at the output shaft position ?

 

[baz]

OK... I'm into this impeller replacement a little more now and have a few questions and advice to others who have a spare in their spares-locker.

I examined my spare Johnson Pump impeller carefully today (one purchased from Ranger Tugs almost 4 years ago for our R-25's Yanmar 4BY2-150 engine). What I found was that the inner serrated bronze bearing is NOT symmetric. At one end there are opposing groves to the longitudinal groves. The other end does NOT have these opposing groves. See photos below.

Now, the instructions do not discuss this asymmetry so I'm wondering what others have concluded if they also observed this difference between both ends. Maybe it's obvious when looking at the impeller housing's shaft... but I dunno at this point.

Also, the instructions that come with my spare impeller state emphatically that petroleum-base products to lubricate the inside of the pump should NOT be used. See photo of this below.

There are some further specific instructions about where to and where not to lubricate using the supplied glycerin.

N.B. Notes for others...
1) When storing a new impeller in one's spare-locker it's important for increasing the 'shelf life' of the impeller by storing it in a dark, cool and dry place. Presumably the 'dark' aspect is for avoiding exposure to strong light that can/will/might cause the impeller's rubber material to deteriorate.

2) To increase the service life of the impeller do not install the impeller in its housing if the boat will not be used for some extended time. Of course, this does not define "extended time" !!!

One end of the shaft bearing

The other end of the shaft bearing

 

[knotflying]

Mike: What location was used to turn the crankshaft ? Was it at the output shaft position ?

On the front of the engine in the center of the main pulley is a nut. On mine I believe it was 22mm. I used a short extension and 3/8 ratchet turning clockwise, looking at the front of the engine.

Regarding your earlier post, I did not take notice of any difference in the shaft. And as I said in an earlier post I used a bit of dish soap to lube the impeller while turning it in. I seem to remember that the directions in my manual suggest using Vaseline to hold the o-ring in place, so that seems a bit contradictory to your directions.

 

[trailertrawlerkismet]

Barry it appears you've tackled the big impeller replacement project, a lot of laying on your belly with stretched out arms but well worth knowing how to accomplish. In any impeller replacement I've done I've had an O-ring and I've (like Mike) held it on with vaseline while reassembling things. I've also always used the glycerin to lube up the housing and impeller for easier insertion. To bend the impeller vanes in the proper direction I've tightened a zip tie around the new impeller, forcing the vanes in the proper direction and to help get it started into the housing. With the zip tie and glycerin the zip tie slides off as you work the impeller into the housing.

Not sure about the difference in the impeller shaft. As to not installing an impeller if it will not be used for an extended period of time........in areas where boats are laid up for 6 months (like a long Michigan winter) it is suggested to take impellers out during this storage period. I think this is what is meant. In reality I'm not sure many people do this, maybe others will comment.

Is the project complete?

 

[baz]

Jim:

The project is not complete as I'm still reviewing info offered here by you, Mike and others as well as other places before diving in on my belly, so to speak.

I'm concerned/confused about the asymmetry of the inner bronze bearing at this time. Do you or Mike recall looking inside the bronze bearing and seeing grooves as I posted photo's of ? I need to have this resolved before I start the tricky belly activities. 😉

It does appear that Vaseline should not be used as Mike indicated because that is a petroleum-based jelly. :roll:

I like the zip-tie technique for holding the impeller vanes at their proper angle as the impeller is slid into its housing.

[EDIT]

I wonder if I can bother you, Mike or others by looking at a spare impeller for the opposing grooves in the bronze shaft bearing ? I'm very intrigued by this and want to understand the purpose of this design if possible. I ask as in the past Ranger Tugs accidentally provided me with an oil filter that was not compatible with my Yanmar 4BY2-150 engine. I got as far as removing the old filter and started the replacement with the one Ranger Tugs gave me only to find it did not seat down correctly. This confused me no end until after discussing with Ranger and discovering it was the wrong type filter for my engine. I had to replace the old filter until obtaining the correct filter. I don't want the same experience with replacing my impeller. :roll:

What type engine do you and Mike have ? Is it the Yanmar 4BY2-180 for example ? If so I'm wondering if Yanmar changed the impeller design some from the one used for my 4BY2-150 engine ?

My new impeller is on the boat and I'm at home so I cannot post the exact Johnson Pump parts number for the impeller. I should have noted that for my earlier posting.

When I perform the impeller replacement I will use Mike's detailed instructions and annotate them with photos as I go through the replacement process. I will then post all this into my Photo Album as a permanent record for others who want to try this DIY project. Of course it will be specific to the 4BY2-150 engine on a MY2010 R-25.

 

[baz]

Here's some more info on installing the impeller... plus Johnson's install instructions...

Johnson's instructions that were cut off from photo posted above...
Installation instructions for pump impeller
Warning!
There is a risk of water leakage when the impeller is being changed. Check whether there is a siphon effect in the pipe before doing the change.
1. Open the pump cover to gain access to the impeller.
2. Inspect the inside of the pump for wear, and clear any muck out. Change worn components as necessary.
3. Change the impeller shaft seal if one is included.
4. Lubricate the lip seal with glycerin (do not lubricate mechanical seal).
5. Lubricate the inside of the pump with the glycerin included in the kit.
6. Install the new impeller with a rotating movement in the direction that the impeller will turn in, please refer to the illustration.
7. Lubricate the O-ring/gasket with glycerin. Install the O-ring/gasket and cover.

I called Ranger Tugs and spoke with Richard Becker about the circular grooves at one end of the bronze shaft bearing. He confirmed that their impeller part they sell has the exact same groove design. He surmised they are there to facilitate a Yanmar tool for extracting the impeller... presumably a tool that engages the grooves so the impeller can be easily pulled off its shaft. This tells me there a right and a wrong way to place the impeller on the shaft. The circular grooves must stay exposed for the tool engagement to work.

The Johnson Part # is 09-1028BT-1 just for the record.

Questions for Jim and Mike...
1) How did Jim and Mike remove the old impeller ?
2) What technique was used ?
3) Does the impeller sit on the shaft completely or does about 1/2" of the impeller sit proud of the shaft's end ?

Thanks.

[EDIT]
One more issue/question... It seems that I must remove the Yanmar engine's beauty covers to gain full access to the impeller pulley etc, as well as removing the cabin's wooden step's riser and having the step's lid fully open. It also appears that having the circular floor plastic hatch removed where the fuel tank's shut off valve is located will also provide me a line of sight to the impeller and the housing bolts on backside of the pulley. Is all this correct ?

 

[tlkenyon]

I have read a lot about making sure the impeller vanes face in the proper direction when inserting the impeller. I installed a new impeller using a cable tie and mistakenly (kinda dyslexic) got ALL the vanes pointed in the wrong direction. Instead of taking the impeller out, I rotated the pump shaft (no belt) in the proper direction to see what happened. Within one full turn, all the vanes were pointed correctly. As the vanes pass thru the part of the pump body where they are fully, or almost fully, extended, they then become pointed properly as they enter the smaller radius portion of the pump body. Nothing I did could make the vanes stay pointed in the wrong direction, so I came to the conclusion that vane orientation is not critical in impeller installation.

Is this a mistake? Did I make a faulty conclusion?

 

[baz]

tlkenyon: Your explanation for having the vanes aligned correctly sounds AOK to me. Thanks for the tip. When I do mine I will take a photo of the exposed impeller vanes inside the housing before I remove it so I have a record of which way the vanes should bend. Thanks for the heads-up. 🙂

 

[trailertrawlerkismet]

Barry:

I just checked my old impeller and it is exactly like yours, not sure about the one I installed. I used a pair of needle nose pliers to pull the old impeller out. I pulled on a vane a little then rotate to another and another until it worked its way out. When I installed my impeller it went in all the way flush with the housing. We've got the 180 in an R27 so I'm not familiar with your step set up but I do know the project is a challenge. The good news is that with one under our belts it should become easier the second time around.

 

[knotflying]

Barry,

I have the same engine as Jim, 4BY2-180. When I get back to the boat I will take a look at my old impeller to see if it has grooves. When I took my Yanmar diesel class there was no mention of putting in the impeller with the grooves facing in or out. I removed my impeller same as Jim Needle nose plier, pull and turn once it was out half way I could pull it with my hand. If those grooves are for a removal tool then I wouldn't be concerned cause you aren't going to use the removal tool, just like you aren't going to use their special belt installation tool. Do make sure that when you install the belt that it is entirely sitting in the appropriate grooves on the pulleys.
The whole impeller change is actually more intimidating then it actually is. Kind of like golf, no brains required, it is all muscle memory! Hopefully I have not insulted some golfers out there. :evil:

 

[baz]

Thanks ALL for posting your help and responding to my questions etc. Most helpful.

I will post back here after I've successfully replaced my impeller. I will take Mike's detailed instruction, add any additional notes/photos needed for doing the work on the 4BY2-150 engine installed in our MY2010 R-25 and post to my Photo Album on this site just to make a permanent record for others.

I'm very interested in knowing what shape my old impeller is in after 270 engine hours and nearly 4 years of use.

As an aside, I did read in another forum that some people have suggested adding a strainer/filter with not more than 1/8" mesh downstream of the pump to catch any errant impeller vane pieces that get shed to avoid them entering the engine's cooling system.

Now I need to go down to my Athletic club to tune up my stomach muscles and reboot my brain... :lol:

 

[knotflying]

A strainer downstream from the pump outlet is a good idea, but if you think changing the impeller will be difficult, try installing and maintaining that strainer!! :lol:

 

[baz]

Mike: I'm a little confused with your impeller replacement instructions, and it may simply be that your instructions are specific to your R-27 and your Yanmar 4BY2-180 engine. For my R-25 with the Yanmar 4BY2-150 engine all of the work for replacing the impeller HAS to be done from the cabin side with access being through the cabin step that has its riser removed and its lid opened to its vertical position.

The following instruction you gave specify the work is done from the cockpit side and this confused me... For me this has to be done from the cabin side as I mentioned above. I'm guessing that your access from the cockpit side is done due to your engine being installed further aft and out of the cabin area's step.

• The following work is from cockpit side. Having 2nd person looking from inside helps a bit
• Turn impeller pulley so that pulley slots allow access to hex bolts
• Put a piece of paper towel on male end of extension and force hex socket onto extension. This will prevent the socket from falling off.
• Feel your way to the hex bolt and insert drive into bolt and then attach ratchet. Just loosen bolt, do not remove.
• Do this same procedure for the three remaining bolts.

 

[baz]

So here is a quick set of photos showing my access to the impeller on our MY2010 R-25 with Yanmar 4BY2-150 engine... and it's pretty darn tight... and it's a shame I don't have cameras in my finger tips for this exercise. :lol:

Today I began getting things ready for the impeller replacement and discovered I will not need to remove the engine's beauty covers to get at the impeller pulley etc. However, I'm sure my arms will get torn up a bit on the fiber glass edges.

Below shows access to the front of the engine from inside the cabin with the cabin step fully opened up. Note the round access hatch in the floor in front of the step. This hatch can be opened and exposes the fuel tank's shut off valve and by laying down on my belly and shining a flash light toward the engine I can clearly see the impeller pulley and one of the holding 6mm hex bolts.

Below shows what I can see when on my belly looking down through the round hatch hole in the floor.

Below shows how much room I have to get my hand down to the pulley along with my socket wrench for hooking to the 4 6mm hex bolts after I slip the pulley belt off with my screw driver shank.

Here are the tools required for this DIY project. I should really also add my two 4' long flexible pickup grabbers - one with magnet on its end and the other having little grab spikes on its end for non-magnetic items. These would be used if I drop bolts into the bilge below.

 

[knotflying]

Well, I am sorry to say that I can't tell you specifically how it is on the R-25. However, if you have clear access from the cabin then it should be much easier for you since you will be able to see what you are doing. In any event the steps should be similar only you won't be working as blindly.