420AC: 3116 Seawater Impeller Change question

[jeffsuwanee]

Since my recent purchase of the boat, this will be my first seawater pump impeller change with this motor/pump arrangement. The engine is a CAT 3116 and upon first observation of the pump mounted to the engine, it appears that the only white paint missing around any of the bolts on the pump (which I think is a Sherwood 1710) are on the bolts on the widest exposed cover of the pump. Could it be, with this arrangement,that the cover is direct access to the impeller and, in fact, I might not even need to disassemble the entire pump from the engine in order to change out the impeller ?

Thanks in advance,

Jeff

 

[Gofirstclass]

Jeff, I'm not sure about your 3116, but on my 3406's the cover over the impeller is held on by five bolts. They're an odd size bolt (metric, I think 8mm) which is unusual for a CAT engine. We just changed our impellers recently. The stbd engine was a breeze because the impeller housing is on the right side of the engine so it was easy to get access to. The port engine was a different story. I couldn't get enough room behind the impeller to do any serious pushing on it, so I used some longer bolts and jam nuts to get the impeller to slide in.

Here are some shots of what I did....
As you can see, the filter sits right in front of the impeller housing with only about 5" to 6" of clearance...

I bought five 4" long x 8mm bolts and 10 nuts, then used the nuts as jam nuts. I'd tighten the plate down a bit and that would force the impeller into the housing. Then I'd take out each bolt, one at a time, and move the jam nuts down another 1/2" and repeat the process until I got the plate close enough to the housing to replace the long bolts/jam nuts with the original bolts.

Good luck!

 

[fwebster]

Here is your pump:

http://www.depcopump.com/catalog110/113.pdf

Look for 3116 Cat.

The impeller is under the plate on the rear held on with 3 bolts. Remove the plate and there is the impeller. There is no need to remove the entire pump from the accessory drive housing. Get a Sherwood impeller kit before you start. The Sherwood kit has decent instructions for you to follow so its going to be hard to make a mistake.

Also, if your pumps have the right impellers in them now, the internal bore is threaded with 3/4-16 standard threads. You won't need a puller; just get a 3/4" fime thread bolt about 2" long and screw it in the threaded bore of the impeller. The bolt will contact the shaft and will jack the old impeller out as you screw the bolt in.

 

[jeffsuwanee]

Frank, thanks for taking a few minutes to respond to my post...as usual, your advice is exactly what I needed. Thank you!
I will attempt the swap out this afternoon. It looks as though there is no gasket replacement necessary as the "O" ring appears to be the only item behind that 3 bolt plate.

GoFirstClass...thank you as well, for the advice and pics.

Jeff

 

[twyant]

When you get the new pump it will have a new "O" Ring Change it too also check the where plate.( the back cover )