Help removing perkins 4.108 raw water pump

[squarpeg]

I am having problems and needs some advice. Perkins 4.108 has what appears to be the Jabsco water pump. It has been leaking for years now. I need to replace it. The issue is it is very inaccessible. The front of the engine sits close to a bulkhead. I have tried to remove the 4 nuts that are securing the pump to the engine. I do not think it is going to happen. I can not even get an open ended wrench on most of them. They also appear badly corroded. The pump seems to be attached to what I think is called an adapter plate. I found a photo that looks similar to my setup. You see the secondary ring behind the actual pump body. This ring has 4 bolts that I was able to get out. I put a good deal of pressure on the pump, wiggled it a bit but it remains rock solid.

Can anyone tell me if this pump can be removed with those 4 bolts out? I don't want to reef on it without knowing. or are the bolts that go through the body of the pump still holding it on? I have read some of the other posts on this and there is also an issue of alignment. I am calling this adapter plate but then in previous posts someone says " The alignment procedure is to align the seawater pump adaptor (drive) plate, which bolts onto the drive gear with three bolts and holds the drive key that actually drives the pump." All confusing to me. Can anyone shed light on this? Hopefully that is the case as there is no need for me to remove the 3 bolts shown in the photo.
Thanks

[mike d.]

You should be able to ! It is probably stuck from corrosion ! I would try tapping the housing with a rubber mallet! I have a Perkins Prima 50/Volvo Penta 50 that has a similar setup in that the pump is mounted to a spline on the shaft of motor ! On mine the small bolts came out ok, but I had to use a little elbow grease to get it to start moving ! You have to remember that the tolerances are close on the machined surfaces, and if you have rust on them, you know the rest !

[squarpeg]

Well that sounds positive but would love to here from someone that actually has this engine before I whack it. I was able to take a picture of my actual setup. You see The bolt holes in the outer ring. This ring I am calling the adapter plate and wondering if it will just pop off with some more force, bring the pump with it. Anyone else know for sure?

[DougR]

On the two separate 4-108 engines that I used to own, the flange on the water pump itself was the same size as the plate that you are calling the adapter plate.
The water pump was fastened directly to the timing gear cover with the 4 studs which show in your second photo, the photo without the pump attached.

Because the four studs are attached to a free floating ring on the inside of the timing cover, and because the timing cover itself was just formed sheet steel, there always was a problem keeping this joint oil tight with just the standard gasket. Consequently the pump flange always had a healthy layer of gasket goo of one description or other sealing it to the timing cover.

From your photo there also appears to be a layer of sealant on your adapter plate, and I think this is what is holding the assembly to the timing cover. Make sure all four of the adapter attachment studs/ bolts are removed and the adapter should come off with some persuasion.

DougR

[squarpeg]

Ok so I have received some input on another person who says the "adapter plate" is just that. As you say you did not have one on yours and I am told the sherwood pump has a larger base that fits directly on, no need for the adapter plate. The Jabsco pump has a small base and requires this adapter ring. Thanks for the input.

[jamhass]

I have had amazing luck with a product called "engine tune" from Mercury. Sold as a spray to remove carbon, but does an excellent job of loosening corroded nuts and bolts.

[fish53]

Have you tried a judicious application of heat? A pencil tip on a propane or Mapp torch might soften the sealant. Just a thought but of course the moment I can't get a nut off I drag out the cutting torch. My boat used to have a 4-108 and it was so tight in front I couldn't take the cover screws off of the cover. I ended up replacing the screws with studs and put nuts on them so I could use a wrench. You only need to remove the bolts on the pump flange to remove the pump. After the pumps off you can remove the ring if you so desire. You don't want to remove the drive from the timing case if it's not necessary and replacement is straight forward, just put the slot on the inside end of the shaft on the drive, turn the pump to align the bolt holes and bolt it back on. I never used sealant but there is a lot of oil sloshing around in the timing case so if the mating surfaces aren't real clean and mate well it'll leak, use something non-hardening if you do. Oh yeah, don't beat on it at all, the bronze body of the pump will distort and you'll need a new pump.

[datarat]

Agreed on using heat. This will cause the metal to expand just enough to break the corrosion on the threads. After heat is applied I'd recommend using an impact gun vs a standard wrench or ratchet/socket as this will further help to break the corrosion vs potentially rounding over the bolt head. If you don't have access to an impact gun, using a mallet against a wrench/ratchet would be the next best thing.

Good luck.

[Captain jo]

hello squarpeg

I have a 4-108 and i just rebuild the pump.

The adapter plate must be left in place because it aligns your pump with your timing gear, If you remove it and don't have the alignment tool when you put it back, you could damage the motor or the pump.

if you rebuild your pump there is a kit sold by Part For Engine (UK) and they supply that tool in the kit, if its easier to remove the plate.

[squarpeg]

I ordered a new pump and they include the alignment tool with it. All is good.
Thanks

[mtniner]

I know this is an old thread but I'm hoping this is the right place for my question.


I believe my water pump">raw water pump is misaligned on my Perkins 4.108. I have the Perkins raw water pump alignment tool and am about to remove the adapter plate from the engine but I noticed that the tool doesn't fit into the hole in the adapter plate.

Does anyone have the Perkins raw water pump alignment tool and if so, could you measure the outside diameter?

The tool I have measures OD 34.90mm, but the adapter plate hole ID that the tool is supposed to fit into only measures 34.15mm. Did I somehow get the wrong alignment tool?

Thanks!