Onan raw water pump shaft and seal

[larryeddington]

Has anyone pressed this bearing from shaft and found a replacement either same or using two traditional bearings with a spacer in between? This is the bearing and shaft from an Onan 6.5 raw water pump. Looks like it should press off but bearing has no numbers only name Hoover NSK on it.

[larryeddington]

Has nobody had this issue before and resolved?

[prowlersfish]

Larry try talking to Depco pumps . Thats all the do is pumps .

http://depcopump.com/

[Commissionpoint]

Yeh. Water pump shaft assy. Onan MCCK.

Spendy....

[larryeddington]

Thx paul and commish, will explore Depco. Me thinks if Onan got that hoover nsk bearing, it must exist somewhere. I am going to visit my bearing supply house tomorrow and explore alternatives. I found where someone on Chris Craft replaced the whole pump with a Jabsco 2620 which are about $250 as one solution, they put a larger pully on it to slow water flow back to original.

On the other hand the bearing is likely made special for onan. Me also thinks I can possibly press two bearings on shaft with a spacer between to gain near same configuration.

Before I fight the pump fight will make sure the genny will run. I cleaned the carby and choke pull off mechanism and electrics work fine.

[Commissionpoint]

Larry. Seems like you are doing all the right things to get her to run. Make sure you check the points good too. They are notorious for making problems.

Hopefully you don't have to go this route:

http://www.pumpvendor.com/Onan_131-0257.html

[gardnersf]

Try the Onan forum at SmokStak as well.

http://www.smokstak.com/forum/forumdisplay.php?f=1

[larryeddington]

Assuming the genny will run correctly, I will use that alternate pump mentioned above and adapt it before I spend 1200 for a pump, or 355 for a shaft and bearing, though that could be a possibility but I bet I can fix the bearings on existing shaft with multiples and spacers.

If I resolve the bearing shaft issue I will document it for the good of the Trojan group.

[larryeddington]

The bearing and shaft from Onan shown in picture above is made as a unit and does not press off. However I found a bearing from NSK that is the same diameter, same length, same shaft diameter, shame shaft length from one end but longer on other end. It is now at machine shop getting the long end dressed to the various sizes and new groove for Circlip as well as having a keyway cut for the new pulley. Bearing $31, 3.5 inch pulley $9, machining about 2.5 hour at $60 each for cash. Once finished and working I will post pics and part numbers. Seems to beat the Heck out of $350 for a bearing shaft. Also I am making an improvement by having an internal snap ring groove machined into the pump housing, to be sure the shaft and bearings are held by a clip as well as friction. Other brand have them so will mine.

[larryeddington]

Success, I now have a brand new bearing for the Onan, and the various parts, seal, two impellers.I will take pics of shaft and assorted MCCK assorted water pump parts. I made some alterations which I think makes it better and stronger, such as used new pully that has 1/8 inch keyway which was also machined into bearing shaft (no slipee). Inside pump bronze housing I had a grove cut to place a snap ring that will insure the bearing stays where it belongs after I press in. I figured if Sherwood and Jabsco used them it would be a good addition. I have read many accounts of loose pulleys, hopefully it will be solved with the keying, works on propellers. The beast is a $450, bearing and shaft cost $31 plus pulley $9 and labor $160. Total cost of bearing, shaft assembly $199. Will take pics of part numbers as well.

Here are pics:





Hopefully with improvements the pump will be long lived.

[larryeddington]

pics added above.

[alexander38]

What a great post.

[prowlersfish]

Looks good Larry

[larryeddington]

Well I actually got the MCCK cranked and started without raw water pump. Installed raw water pump and would not stay running. Gonna go through the usual tune up stuff plugs points etc, and oh yes new battery was only getting 11 volts, not a good spin. Batteries for Genny and engines are 09 vintage to am replacing them with new and bigger batts. Me thinks result will be better then.

When it was running we were getting 85 V ac but could tell not running up to speed.

We did get raw water flow through engine and out exhaust, Yahoo.

[Commissionpoint]

When it was running we were getting 85 V ac but could tell not running up to speed.

Use a good modren inductive light to check timing (21* but it will float high to about 23* on one side due to the nature of the plunger style points, though I digress... ) and runnning RPM's. Use the 4 cyl setting and do a little math to make sure you are getting +/- 1800 Rpm's.