noticed I was not discharging water on my gen set---1981 6.5 onan. purchased a new impeller, but when looking at the set up it looks like the carb has to come out to remove the plate. Am I correct? Any easy way? Water pump is behind the carb.
Need advise---
impeller on 6.5 onan generator
Moderators: BeaconMarineBob, Moderator, BeaconMarineDon
Job complete. The old impeller was worn, but not broken, Took me over two hours but I left my manuals at home. I had to remove the pump (I’m sure that’s the only way) and had to figure that out. Of course I dropped a wrench, socket, allen wrench and nut at various times, but found a screwdriver under the genny from the previous owner. Not too often I end up with more tools than I started with :.
If anyone is looking to do this job, here it is in a nutshell
1. Disconnect genset from battery
2. Remove SW hoses from SW pump
3. Remove belt cover (on my boat I couldn't)get it completely out of the way, but had it off the mounts
4. Loosen Allen screw on pump belt pulley
5. Remove pulley from pump shaft
6. Remove pump mounting nuts with 7/16" open end wrench. Do not drop lock washers and nuts into bilge. A flexible shaft nut driver and socket are helpful here as well.
7. Get nut and socket out of bilge because you didn't listen to step 6
8. Remove bolts from back of pump mounting holes
9. Remove pump. I found it easiest to rotate it 90 degrees and pull the pump head up past the spark arrestor.
10. Pick up the spacer plate out of bilge
11. Remove 4 screws and pump cover. You may have to tap the sides lightly to get it to loosen up
12. .Remove old impeller. Note the direction of the vanes when removing
13. Clean pump housing
14. Remove old gasket material
15. Apply Low Temp grease to inside of housing , shaft and impeller
16. Install new impeller with vanes matching previous orientation.
17. Place new gasket in housing
18. Replace pump cover and screws
19. Guide pump and spacer plate back into place
20. Put bolts through from back of mounting block and finger tighten nuts and lock washers
21. Replace pulley on pump shaft
22. Tighten Allen screw on pulley
23. Replace belt on pulleys
24. Pull the pump upwards to get the belt tight. Then tighten the pump mounting nuts. I found the right one had easier access
25. Tighten remaining mounting nut
26. Check belt tension. Repeats steps to get it tight
27. Replace SW inlet and outlet hoses and tighten clamps
28. replace belt cover
29. Reconnect GenSet to battery
30. Run Gen set and check for water flow
If anyone is looking to do this job, here it is in a nutshell
1. Disconnect genset from battery
2. Remove SW hoses from SW pump
3. Remove belt cover (on my boat I couldn't)get it completely out of the way, but had it off the mounts
4. Loosen Allen screw on pump belt pulley
5. Remove pulley from pump shaft
6. Remove pump mounting nuts with 7/16" open end wrench. Do not drop lock washers and nuts into bilge. A flexible shaft nut driver and socket are helpful here as well.
7. Get nut and socket out of bilge because you didn't listen to step 6
8. Remove bolts from back of pump mounting holes
9. Remove pump. I found it easiest to rotate it 90 degrees and pull the pump head up past the spark arrestor.
10. Pick up the spacer plate out of bilge
11. Remove 4 screws and pump cover. You may have to tap the sides lightly to get it to loosen up
12. .Remove old impeller. Note the direction of the vanes when removing
13. Clean pump housing
14. Remove old gasket material
15. Apply Low Temp grease to inside of housing , shaft and impeller
16. Install new impeller with vanes matching previous orientation.
17. Place new gasket in housing
18. Replace pump cover and screws
19. Guide pump and spacer plate back into place
20. Put bolts through from back of mounting block and finger tighten nuts and lock washers
21. Replace pulley on pump shaft
22. Tighten Allen screw on pulley
23. Replace belt on pulleys
24. Pull the pump upwards to get the belt tight. Then tighten the pump mounting nuts. I found the right one had easier access
25. Tighten remaining mounting nut
26. Check belt tension. Repeats steps to get it tight
27. Replace SW inlet and outlet hoses and tighten clamps
28. replace belt cover
29. Reconnect GenSet to battery
30. Run Gen set and check for water flow
31. Fire Genny up (where's Forest?)
32. Turn AC on
33. Make sandwich
34. Turn TV on
34. Enjoy sandwich and cold beer in cool salon watching the ball game
35. Reply to group about successful rebuild
32. Turn AC on
33. Make sandwich
34. Turn TV on
34. Enjoy sandwich and cold beer in cool salon watching the ball game
35. Reply to group about successful rebuild
Last edited by rossjo on Wed Jun 17, 2009 10:49 pm, edited 2 times in total.
Captain Ross, 2009 Trojan Boater of the Year
"Viva Mahia" F32 Cummins 6BTA diesels,
"Mack Attack" Chaparral 244 Fish, SeaPro 180, McKee 14, Montauk-17
"Viva Mahia" F32 Cummins 6BTA diesels,
"Mack Attack" Chaparral 244 Fish, SeaPro 180, McKee 14, Montauk-17
^^^^^^That's pretty specific. 
For future Onan Generator help you should go here
SmokStak forums
http://www.smokstak.com/forum/forumdisp ... b20708&f=1
My electronic ignition DIY is on there and there is a ton of people with great knowledge of these things. Bill on there is a former Onan Tech with tons of know how....
For future Onan Generator help you should go here
SmokStak forums
http://www.smokstak.com/forum/forumdisp ... b20708&f=1
My electronic ignition DIY is on there and there is a ton of people with great knowledge of these things. Bill on there is a former Onan Tech with tons of know how....
79' Carver 28' Mariner
I want another Trojan, preferably a Tri Cabin
I want another Trojan, preferably a Tri Cabin
I saved this from a post a while ago when I had to do it. AFter the first time, I didn't get the pump tight on the shaft and pulled the impeller and chacked it. I had the removal down to under 15 minutes the second time.