Yanmar 4BY2 Impeller Replacement on 2009 R25

[Langlois]

What are the exact steps/tools for replacing the water impeller on a Yanmar 4BY2 engine in a 2009 R25?
Why do I ask?
Because just had a mechanic try and he could not do it.
Now we are looking at cutting the floor open to change the impeller because he there is no access.
Has anyone changed a water impeller on a Yanmar 4BY2 engine on a R25?

 

[walldog]

What are the exact steps/tools for replacing the water impeller on a Yanmar 4BY2 engine in a 2009 R25?
Why do I ask?
Because just had a mechanic try and he could not do it.
Now we are looking at cutting the floor open to change the impeller because he there is no access.
Has anyone changed a water impeller on a Yanmar 4BY2 engine on a R25?

It can be done and has been done countless times without modifications, but this would make it a bit easier.


viewtopic.php?f=5&t=4820&p=35107&hilit=impeller#p35107

 

[walldog]

What are the exact steps/tools for replacing the water impeller on a Yanmar 4BY2 engine in a 2009 R25?
Why do I ask?
Because just had a mechanic try and he could not do it.
Now we are looking at cutting the floor open to change the impeller because he there is no access.
Has anyone changed a water impeller on a Yanmar 4BY2 engine on a R25?

Here are a couple of links to articles in this forum that may help you.

viewtopic.php?f=6&t=3716&p=27514&hilit=impeller+replacement#p27507

The 25 is a bit tighter, but same principle applies as Andrew Custis states:

The R25 classic and R25SC are two different animals. The SC has a bit better access through the forward hatch which I have changed several from this location. Although its not like the R21EC and you lay on your belly, I find the impeller access still very manageable. The R25 classic is a bit tough to reach but still doable. If you want to make it easier, cut the fiberglass back a little bit and it will make for a much easier job.

Feel free to contact is directly if you have any questions.

253-839-5213

Andrew Custis

 

[TonyM]

I copied this from a posting last year on Tugnuts, by knotflying on Wed Feb 06, 2013
This was for an R-27 but should be close enough for you after you get your access challenges worked out 😀

RAW WATER PUMP IMPELLAR REPLACEMENT
Tools
22 mm socket 3/8 drive
6 mm hex male 3/8 drive
3” extension
3/8 drive ratchet
Long needle nose plier
¼ inch drift pin or Phillips screwdriver of same diameter
Paper towel
• Shut seacock valve
• Turn off engine switch
• Disconnect engine positive wire
• (This one may not apply to you) Remove interior panel that has 110 and 12 V outlet. This makes sliding and removing slide panel easier and allows for better vision from side into engine

• Remove Impeller pulley belt – From cockpit side have one person push on belt at bottom of impeller pulley. Have 2nd person in cockpit on port. Reach into crankshaft pulley with 22mm socket, extension and ratchet. Turn engine clockwise (as if you were looking aft) and belt will work off.

• 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.
• Now put a piece of paper towel on the end of the hex drive and force that into the hex bolt. If you loosened your bolts enough you can screw them out with just the extension and no ratchet.

• Once all the bolts are out you can slide the pulley and housing out and the person inside can handle it through the step access.

• Get a good set of straight needle nose pliers and insert them with one end in shaft hole and one end between blades and yank. Once you have it out half way you can turn clockwise while pulling out and you should have it in hand.

• There is a small O-ring type washer on the motor side housing. Mine looked good so I did not replace it.

• Insert new impeller by working it in turning it clockwise and inward pressure. Once started push it in.

• Now insert pulley and shaft assembly. Line up holes using the drift pin in one of the holes.

• Do the paper towel trick, using only the extension and screw in like you would a screwdriver and be careful not to
cross thread the bolts. First turn counterclockwise then clockwise so as to be sure you are not cross threading and hand tighten. Do this for the remaining bolts.

• Now remove the paper towel piece in between the 6mm drive and the bolt and now tighten all the bolts using the ratchet.

• Now with the help of the 2nd person. Place the belt around the drive pulley and start it on the impeller pulley at the bottom

• Go back to your removal positions and turn the engine clockwise while the impeller person works the belt on.

• Visually inspect from the inside to be sure belt is on both pulleys appropriately.

• Reconnect engine power cable, turn on engine battery switch and open the seacock.
• Check for any leaks.

• Start engine, check that water is discharging, and look for leaks.

• Hi five and have a beer.

 

[nzfisher]

Langlois

I gave up on trying to fit through that little access hatch because I wanted to be able to change the impeller while at sea. I cut out the step and replaced it with a one piece tread and riser that rests on the remnants of the old step. It is held in by the locking action of eccentric clamp that is fastened to the tread and locks to a "u" type bolt fastened to the wooden stretcher that passes under door. It is removed by taking off the furry access panel on the port side of the stair to open the clamp. I now can replace the impeller in about an hour and access the front of the engine while at sea. A fair amount of work but better than the frustration of blind access in the black hole. The finished stair can be viewed on photos of Swims With Tuna.

 

[baz]

Here's another posting I'm sure you will enjoy reading. It includes my story of me replacing the raw water impeller on my 2010 R25. Good luck.... 🙂 Be aware, the R25SC and the R27 are very different 'beasts' wrt access to the impeller assembly.

http://www.tugnuts.com/viewtopic.php?f=2&t=3732&hilit=impeller

 

[Paul and Tanya]

Replaced mine (impeller that is) last week. Thought I was pretty mechanically inclined given that I've built cars, engines, etc. Typically a belt is installed and the you adjust the tension. Doesn't work that way in this application. If I had read the instructions in this thread, I could have saved myself some time. Anyway, hardest part for me was keeping the darned (I used a much more colorful adjective during the install) o-ring in place.

 

[knotflying]

A little Vaseline on the o-ring helps keep it in place.

 

[baz]

A little Vaseline on the o-ring helps keep it in place.

That, and some good luck and a dose of patient is required from my experience. The vaseline can hold the O-ring in place for just a short amount of time and then it will start to ease itself out of the groove. This means you have little time (maybe 5 seconds at best) to slide the impeller housing with its pulley into the pump assembly to snug up and keep the O-ring in place while you insert and tighten up the 4 bolts. My approach to this was to have the pump housing and pulley assembly held in my right hand and using my left hand to place and push/hold the O-ring in place in the groove and then quickly swinging/moving the pulley assembly over with my right hand to slide it's shaft quickly into the impellers shaft hole and snug it's face up to the pump assembly as fast as I could. The danger here, is that if the O-ring dislodges from the groove during this process it will get crimped when tightening the bolts and more than likely will result in a leak.

So, be sure to make a leak test after you have the impeller pump assembly put back together and have the pulley belt back on and the engine run for a while.

Also, make sure the pulley belt is in fact riding in the pulley grooves correctly. It's very easy to think you have the belt on correctly and be off by one groove. The best way to determine if the belt is correctly positioned in the pulley grooves is to use your thumb and forefinger to feel the edges of the belt when its fully engaged on the pulley, and check BOTH pulleys for this alignment. If you feel the belt edge is overhanging the pulley's edge then the belt is mispositioned.

This is one very taxing DIY task from my experience.... so good luck. 🙂

 

[Rodeo]

Is changing of the impeller on a 2009 R25 with a Cummins engine any easier? (Just for future reference)

 

[knotflying]

I wonder if just a little bit of permatex dabbed on in a few spots would make it easier for you. I wouldn't use too much though since you don't want the o-ring stuck on and then difficult to remove.

 

[pugtug613]

I was looking at my R27 access to mentally prepare for the fall, when I replace the impellor. A question about the belt. Is there a tension spring? Usually, a serpentine belt has a tension spring.
Chester

 

[baz]

I was looking at my R27 access to mentally prepare for the fall, when I replace the impellor. A question about the belt. Is there a tension spring? Usually, a serpentine belt has a tension spring.
Chester

There's no tension assembly. The belt when installed properly presumably is tensioned correctly.

 

[sportner]

I did the same as nzfisher and cut out the molded step and replaced it with wood. It used to take me and the wife a painful hour and a half to change the impeller. With the step change it takes less than 30 minutes by myself, way better.

 

[baz]

Russ: Many of us are aware changing the raw water impeller on the R27 is much easier than for the R25 (Classic). The OP was asking about the R25 specifically. The R25 already has the wooden step which is easily opened up. The real issue with the R25 is the 'access' to the impeller pump housing and the 4 retaining bolts. Access has to be done via the round porthole hatch opening just forward of the wooden step along with hands/arm stretched down in the small space behind the engine which is no more than 4" in width.

 

[sportner]

My goodness, I thought we all had about the same access, that's a REAL challenge.

 

[captstu]

I'm part way through changing the raw water impeller on my 4BY2 150 on the R-25.

Surprisingly easy to remove the belt, the four 6 mm socket bolts retaining the pump, and the housing. I was even able to pull some of the broken impeller pieces out of the housing.

Now, two questions:

1. How do I hold the "O" ring in place while I slide the pump head home? Can I just put the "O" ring on the removable part and wiggle it into place? Since there is no retainer in the grove, I don't see how to keep the ring in place for more than a few seconds.

2. How do I compress the impeller enough to get it into the housing? I was thinking of bolding the removable part in place and turning the pulley until the impeller blades glide into place??? There must be a better way, but with such limited access I can't compress the impeller by hand. If this is the "right" way, what size bolts should I use?


Can someone provide the P/N and source for the "run dry" style impeller - the extra cost is easily worth it if I have to replace the impeller less often.

Thanks for the steps to get me this far.!! /Stu

 

[Brian B]

Put some Vaseline in the groove on the housing and press the O ring into it, it should stay in place.
I've taken a zip tie and compressed the impeller blades in the right direction to get it started into the housing. Once it's part way in cut the zip tie and push it in. It helps to lubricate the inside of the housing with glycerin that is usually supplied with the impeller. Some folks use dish soap also.
Not so sure if the run dry impeller means that it can be replaced less often.
When you re-install the belts make sure the grooves in the belts are lined up correctly with the grooves in the pulleys. It's easy to misalign them.

 

[captstu]

Brian,

Zip tie may be the key - I'll try that tomorrow morning. The normal push and twist technique just doesn't work for me with such a large impeller.

I plan to try contact cement on the "O" ring - tried lubaplate, KY jelly and the stuff that comes with the impeller - no luck so far. Think I'll press in the impeller first so the "O" ring isn't in place for long before the cover goes on.

There has to be a better way to build these pumps.

Thanks for the zip idea /Stu

 

[baz]

Stu: Are you referring to the SpeedSeal For Life impeller cover. If so post back as it has to be ordered from the UK and best done via telephone to ensure you get the plate with correct bolt holes and bolts etc.

BTW... I installed my SpeedSeal for Life a few weeks ago on my R-12EC and it took me all of 5 mins. To change the impeller on the R-21EC I estimate it will take me no more that 10 mins at best.