Water Impellers

[Dennis]

I have a 2001 SeaRay 410 with Cat 3126 engines. I have typically had work done by the dealer, but I am now finding myself with more time and an interest in attempting to do maintenance work myself. Which brings me to my question I need to replace the impellers in both engines and the generator which is a Westerbeke 7.6KVA. I have tried to do a search for instructions on changing out the impellers but haven't been very successful. Can anyone point me to some instructions and provide insight on difficulties or what I need to be careful with if I take this on.

Thank you in advance for any insight / help.

Dennis

 

[tobnpr]

I have 3208's so can't comment on your particular engines, but I was going to do mine last month. Bought the impellers from CAT, then took a good look at my port engine and realized NO WAY was I gonna be able to get to it- on the outboard side of the engine up against the bulkhead and fuel tank...of course, the stbd engine was a piece of cake.

I had my mechanics come out to diagnose/repair an electrical glitch on one of the engines and had them do it. Fortunately, one of them is small in stature (I could never have squeezed in over top of the engine) and it was necessary (easier, I should say) to remove the entire pump and install the new impeller than doing it with the pump in place. Took both of them to work the pump in and out of position and get a wrench on the bolts. They had done it a million times so it was NBD for them, but it still was a two-man job.

There are fancy impeller pullers but they just used a screwdriver and carefully pried out the old impellers, new ones pushed right in. I've seen some guys use a wire tie to compress the impeller blades if necessary to help get it into the housing. It's a really simple job IF you can get to them...

 

[earthmover17]

I have a 2001 SeaRay 410 with Cat 3126 engines. I have typically had work done by the dealer, but I am now finding myself with more time and an interest in attempting to do maintenance work myself. Which brings me to my question I need to replace the impellers in both engines and the generator which is a Westerbeke 7.6KVA. I have tried to do a search for instructions on changing out the impellers but haven't been very successful. Can anyone point me to some instructions and provide insight on difficulties or what I need to be careful with if I take this on.

Thank you in advance for any insight / help.

Dennis

I have 3196's and I just did my impeller pumps last year. I don't know if yours are the same as mine or not but a few thoughts. I took my pumps to a local shop and had them rebuilt($2000.00). This was with new impellers. The impellers($250.00 apiece) run in a machined surface inside the pump. My surfaces were hazed and cracked and I can't remember if they resurfaced or pressed in new ones. The juxt to this is just replacing the impellers might not be all they need.
Replacing impellers is a fairly simple job. You pull either split the pump or pull off a plate on the back of the pump, pull out the old one(some have a tool to pull old one usually comes with new impeller), and put in the new one. Remember to identify which the impeller blades are turned as it has to go back in that way. Gensets pretty easy. Usually 2 or 3 1/4 20 bolts that hold it together. Just split it and impeller should slide out. Remember which way blades are turned.
Jack

 

[Boulder GT3]

I have 3196's and I just did my impeller pumps last year. I don't know if yours are the same as mine or not but a few thoughts. I took my pumps to a local shop and had them rebuilt($2000.00). This was with new impellers. The impellers($250.00 apiece) run in a machined surface inside the pump. My surfaces were hazed and cracked and I can't remember if they resurfaced or pressed in new ones. The juxt to this is just replacing the impellers might not be all they need.
Replacing impellers is a fairly simple job. You pull either split the pump or pull off a plate on the back of the pump, pull out the old one(some have a tool to pull old one usually comes with new impeller), and put in the new one. Remember to identify which the impeller blades are turned as it has to go back in that way. Gensets pretty easy. Usually 2 or 3 1/4 20 bolts that hold it together. Just split it and impeller should slide out. Remember which way blades are turned.
Jack

A little more detail if you would. I've never run into hazing or cracking on the pump housing. Do you know what caused it? Also, I assume the rebuild included seals and bearings. Did they do anything else? How many hours were on the pump?
thanks.

 

[Warren]

There are other threads on this subject do a search under "Cat impeller". But another important tip for the first time change - there is a key inserted into the impeller shaft to hold the impeller in place so it spins with the pump shaft. Ensure that the key is on the TOP of the shaft when you remove the cover plate. You may have to push the starter switch for a fraction of a second (do not start the engine!!!) to position the key correctly at the top. This will prevent the key from accidentally falling into the rubber water hose beneath the water pump which is another job that you will want to avoid.

Good luck!
Warren

 

[Chris1960]

I've just done for the first time on my mechanical 3126's. God what a bitch of a job the old impellors must have been in there for years.
There is a puller you can buy which screws into the end of the old impellor to help pull it out but I found on mine the old thead was rusty so it was difficult to get a grip and then there is a sensor of some sort stopping you getting a good pull on it.
Finally ended up having to pull on each blade with pliers to get it out millimetre by mm (it took ages) then finally came out. Panick about the key which I thought I had lost inside but eventually found in on floor (phew!).
New one back in now with lots of silicone grease and the plastic end cover to stop the threads getting so rusty again and must look at again next year perhaps that will stop it getting so seized in again. Best of luck. not a difficult job really just time consuming the first time, easier second tiime round

 

[earthmover17]

A little more detail if you would. I've never run into hazing or cracking on the pump housing. Do you know what caused it? Also, I assume the rebuild included seals and bearings. Did they do anything else? How many hours were on the pump?
thanks.[/quote
I don't have my paperwork with me on the rebuild but from memory they did the Seals,Bearings and impellers. They also had to replace the shafts as they pitted where the seals run.
I am almost sure that my particular pumps had press in cones($$$$$) that the impellers ride in and these are what I was refering to. Remember I have 3196 Cats others might be different.
Others might weigh in on this but they might be too busy with the Bow Thruster thread.
Jack

 

[fwebster]

Observations:

The 3196 and 3126 have different sea water pumps, but impeller changing is about the same........the problem is going to be access to the pump that happens to be on the outboard side of one engine. I haven't a prayer of getting to mine and I have more room that that on a 410.

A simple puller can be made out od a 5" piece of 3/4"X16 (I think?, mine is on the boat) all thread rod with a nut welded on ot 2 nuts jammed on one end. Start the bolt in the impeller and run it all the way in.......the end of the all thread will push the impeller out once it contacts the end of the pump shaft.

Service parts......bearings, seals shafts......are available from Cat, but rebuilding a pumps gets to be very expensive, and they never seem to last very long before they start leaking again, once you rebuild them. Sherwood is the OEM supplier for Caterpillar pumps, so just buy new pumps from a non-Cat source and save a ton of money, plus you get to start the pump clock over again at zero. I replaced both of mine instead of rebuilding them last time and total cost was about $1500, I did the labor myself, but this way turns a 3 hour job into 15 minute per side.

 

[earthmover17]

Observations:

The 3196 and 3126 have different sea water pumps, but impeller changing is about the same........the problem is going to be access to the pump that happens to be on the outboard side of one engine. I haven't a prayer of getting to mine and I have more room that that on a 410.

A simple puller can be made out od a 5" piece of 3/4"X16 (I think?, mine is on the boat) all thread rod with a nut welded on ot 2 nuts jammed on one end. Start the bolt in the impeller and run it all the way in.......the end of the all thread will push the impeller out once it contacts the end of the pump shaft.

Service parts......bearings, seals shafts......are available from Cat, but rebuilding a pumps gets to be very expensive, and they never seem to last very long before they start leaking again, once you rebuild them. Sherwood is the OEM supplier for Caterpillar pumps, so just buy new pumps from a non-Cat source and save a ton of money, plus you get to start the pump clock over again at zero. I replaced both of mine instead of rebuilding them last time and total cost was about $1500, I did the labor myself, but this way turns a 3 hour job into 15 minute per side.

Why is it all the guys with dirt equipment are the smartest?
Wait a minute I've got dirt equipment. LOL.
Frank I probably should have gone that way but everyone I talked to in my area sung praise for a particular shop that rebuilt these. They walked me through what they did and I was confident with them.
Owning a lot of machinery I typically rebuild everything(pumps,trans,engines,cylinders,) whatever I can get a kit for. It seems in the long run to be more cost effective.
One thing we did not mention is we should all carry an extra impeller for 50 miles from nowhere breakdown.
Jack

 

[Four Suns]

I don't have experience with the Sherwood 1700 series pumps (I have 1800 series which is what I would guess the bigger cats have if they use Sherwood) but you may want to check out SB Marine. I don't want to sound like a marketing guy for Tony (he visits here once in awhile) but they know the 1700 pump so well they redesigned a replacement:

http://sbmar.com/Products/SM-Pump-History.cfm

I'm just a happy customer of some of their other products...

 

[osd9]

I will be replacing my impellers on my 3126's in a 410 this spring. I haven't personnally done it yet, as the CAT mechanic did it for me the first season. I ran two seasons, ~135 hrs, on the current impellers.

I will not be using the CAT part impellers. I bought two replacement impellers from SB Marine (Tony). He replacement impellers do not have the threaded ends to use the 'tool' that FW talks about above.

I did watch the CAT mechanic replace the impellers back in Jan of 2007. The port motor has easy acces. the stbd motor is bit of a challenge. The CAT mechanic's helper, a youngish 5'6"ish, ~145 lb'er, was able to squeeze in there to remove the impeller with the pump in place. I'll let you know how a 53 year old 215'lber fits in there in a few months. I've been told it's easier to just remove the exhaust tube, but I'm not convinced yet.....key will be to pre-medicate.

In either case you will have to lossen and move some 'stuff' that is in the way of the old impeller coming out....see the pic below...

 

[ScanMan]

I have Cat 3196’s – the OEM Pump is 123-0471/197-1328
The Sherwood is G1807/G180701-01
Boat Fix has the impeller kits for under $200 and the pumps list for $1200 and you can find them on the web for about $800

 

[osd9]

Well....I did the impeller replacement on my 410DA with CAT 3126TAs yesterday. I can barely move my fingers to type.....more advil please!!!!

As I stated above, the port side wasn't to difficult. I had good access and everything was right in front of me. Because it was my first impeller change on these motors, it took a little longer than necessary....about 3/4 of an hour. Step one....close the seacocks.

Then I had to loosen and move the fuel line, loosen and move the sensor, and remove the oil pressure sending unit before I could gain enough room for the old/new impeller to come out/in of the pump housing.

Once everything was out of the way, I removed the front plate from the pump and minimal water came out. As per instructions from Seaboard marine, I sprayed a bunch of WD-40 into the housing and around the pumps vanes and shaft. Then I 'bumped' the starter to free the impeller a bit. I was able to get a vise grip on the old impeller and pull it out.

Installing the new impeller, I sprayed some more WD-40 in the housing and on the shaft. I then roatated it into the housing and the hardest part was lining up the key way....and not dropping it. Here's the new impeller installed with rubber cap ends...To hold the cover O ring in place, I put some grease on it and set it in the housing grove.

The stbd motor was the same process, the only difference was access. I'm 5'11" and 215lbs. I'm right on the edge of being able to fit in the area necessary to access the pump/impeller. I started by removing the large fiberglass exhaust tube, which in itself was a job....especially getting it back on. Then I removed the brace that holds the exhaust tube midway down the tube. I didn't do that right away. Next time I will...BEFORE it pokes me in the ass five ways to nowhere.

Once I had the tube removed, I squeezed my fat arse in that area. I kept the main hatche closed, because leaving it open gave me no benefit, and having it closed, allowed for a good shelf to hold tools and provide some leverage.

The only advantage I had on the stbd motor was that I Knew exactly what had to be done and what tools I needed to do it. Other than that, after suffering from 10 gradually higher degrees of charlie horses in my legs, and about 2 1/2 hours later, the job was done!

The old impellers were in there for two seasons and about 140 hours. Other than some discoloring, they still looked new with no splitting on the vanes. I patted myself on the back for replacing the impellers on MY schedule and not waiting for them go bad. I can't even imagine if I had to go fishing for impeller parts on that stbd motor. Anyone who purposely waits for an impeller to fail before replacing them is an absolute moron!

 

[Boatingfool]

One more note if you are replacing the impellers due to failure of the impeller (it fell apart):

Make sure you hose out the water discharge line as if the old impeller failed you may have pieces of impeller stuck in the line. Also hose out the intake/feed line as there could be smal pieces that back-fed and will wreck havock to the new impeller.

Another note if you are replacing the impeller dues to no water suction/movement, but the impeller looks okay when you pull it out:

Check the impeller backing plate. I had one of these worn on my old boat's Westerbeake. After replacing the impeller three times to no avail I machined a new backing plate and wola, she pumped a ton of water!

Hope this helps,

 

[Warren]

Thanks for posting the photos Dominic, nicely done and much appreciated. Any tips to provide re replacing the sensor and the oil pressure sending unit? Did you completely remove both parts for access, did they back off easily, did you plug the holes temporarily? In hindsight would you have vacuumed out the inlet and outlet hoses before replacing the impeller and cover? Did you replace the stb. exhaust tube in the water? If so, any issues?
Cheers,
Warren

 

[osd9]

Warren:

You can refer to the pic above....

Oil Pressure sending unit....I removed it completely with a 1/2" open end after disconnecting the wire. Very little oil came out of the hole. I plugged it with some paper towel and placed the sending unit in a plastic cup with the screw end facing up so no oil leaked out of it. I put new teflon tape on the threads before re-installation.

The Oil Pressure alarm sensor.....First I removed the electric plug and secured it up with the wire from the sending unit. I then used a 3/4" open end to losen the locking nut and then turned the whole unit to face upwards and out of the way. No oil leaked from it.

The Fuel line going in the fuel cooler.....I used an 11/16" open end to losen the locking nut and then moved the elbow out of the way and then re-tightened it. I had enough slack in the hose to move it enough to gain room for the impeller to removed/installed.

There is tons of paint on these motors from the factory, and I added some myself after the job was done to make it look pretty. Getting the sockets and wrenches on the bolts/nuts can be somewhat tricky in the tight spaces.

I saw no need to vacuum out the hoses as there was no debris or impeller vanes present in the housing......not to mention there really isn't any room.

I did the entire job with the boat in the water. It was a real struggle to remove the fiberglass exhaust tube. Before I removed it, I marked both ends with a sharpie so that when I went to reinstall I would be sure that I had it back fully and where it was to start. To get it back on, I sprayed WD-40 on the ends and the hoses and then used a big hunk of wood to pry the ends in to the exhaust hose.

I was able to restart the motors and let them run for about 20 minutes after the job was complete. I checked everything for leaks and no issues.

 

[Warren]

Excellent post Dominic. I hope many profit from this information!
Many thanks,
Warren

 

[dc380]

Dom

Nice documantion of the process to replace the impeller.

It would be real nice if someone with 8.1s could do the same. The Starboard engine would be best, it's easier access to the pump, and to take pictures.

I've printed and read the procedure for replacing the impeller, but I'm still not comfortable tackling it, without seeing it done first. For me there is no substitute for seeing something done that is fairly difficult to do and access.

Once I see something done, I'm good.

 

[osd9]

When I replaced the impellers on my 380DA with 8.1s, I was able to squeeze in and lay on the ER floor between the motors to remove the pump housing on the Stbd motor. I had a buddy topside the whole time handing me tools, rags, mirrors, lights, etc.. On the Port motor, I had to remove the batteries to gain enough access so that I could lay on my side to remove that pump housing. On the 8.1s, IMHO, removing the entire pump was the easiest way.

I posted that sceanario on SRO....

 

[quality time]

Thanks for the detailed post Dom, I plan on tackling this job in a few weeks. I am one of those 145lber's you speak of but I think being 1' narrower in the beam is going to be my downfall. You're right about the cramps, they always come on at the worst times!