Yanmar 6BY2-260 Crankshaft Pulley

T

Tugetherness

New member
Joined
Nov 10, 2011
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4
Fluid Motion Model
C-288 C
Vessel Name
Tugetherness
I am getting myself an education on our Ranger 29, learning to do as much maintenance as I can so as to be more self sufficient out on the water, and this site has been invaluable!

One thing I tackled was replacing the raw water impeller, and I found a lot of posts regarding that job, which really helped. I have hit a snag in completing it, because Yanmar apparently changed the design at some point! After replacing the impeller and reattaching the pulley, the directions on this site talked about using a 22mm socket to turn the crankshaft pulley by hand to work the belt back on. The center of my crankshaft pulley doesn't have a big bolt, but rather 4 small torx bolts or something (I would post an image, but I'm not sure how!). Has anyone had to deal with this issue to get their water pump belt back on?

Thanks
Bill
Tugetherness - R29

 
Bill,
I am familiar with the configuration you are talking about. The only thought I have is to make up a special adapter out of a piece of 1/4 inch steel. You would have to make a round disk and drill four holes that the bolts would slide through. Then In the center I would drill and tap a hole to receive a large conventional bolt. Tighten that down and then weld it on the opposite side to fix it in place so you could then turn clockwise or counter clockwise. There may be an outside chance that you could purchase such a tool from a Yanmar distributor like Mack Boring or Mastry engine, which is in FL.
 
When changing impeller, my mechanic has me just slightly crank engine without starting and this enables him to sucessfully install belt. Hope this helps. Jerry Geisenheimer
 
Thanks for the replies! I think I will try to make a tool to turn it by hand so I can change it when alone, but cranking it sounds like a good trick - I wouldn't have been brave enough to try it.

Thanks,
Bill
Tugetherness - R29
 
For safety reasons, I would make sure you can disable the engine from starting before I would "tap to crank".
 
I have changed the impeller on my engine a couple of times. I bought one of those torx sockets you were talking about. (I am not sure exactly on the size as I am not near my tool box right now) I think I got the socket at a NAPA autoparts store. You just put the socket on one of the 4 bolts and even though it is off center it was fairly easy to turn the crankshaft with a wrench attached to the socket. By turning the crankshaft a half turn of so the belt went back on the pully without too much trouble.
 
Hi Bill.
I have a 2010 R-29 - the Circle T - and this is the procedure which I developed over time for changing the impeller on our Yanmar 6BY2-260. I long ago wrote this procedure in our maintenance book -- the dullest pencil is better than my memory so I write everything down.. and have copied it here FYI. I've learned the hard way how not to do this, but have by now done this successfully several times using this procedure so know it works on our boat. Hope it helps you.

PROCEDURE for Changing Engine Impeller
1. Close engine’s through-hull valve !!!!
2. Using 1/2” socket, remove the 3 nuts holding the engine cover on.
3. Remove pulley belt. Use plastic cake frosting spatula or flat wooden piece (like a paint stirrer stick) to pry belt from right (as you face it) wheel first. Have a second person quickly kick the starter motor with the key (on-off quickly) while putting downward pressure on the spatula/belt as it enters the drive wheel. (Do not use a screw driver as this will scratch the wheel, which will then rust.)
4. Recheck through-hull closed !!
5. Using 6mm Hex head on small socket wrench with extension, remove the 4 bolts holding the Water Pump together. Turn wheel as required to allow access to all 4 bolts.
6. If impeller needs changing, the impeller will come out with the cover plate if you turn the wheel clockwise as you simultaneously pull the cover plate slowly toward the bow of the boat. Unit turns clockwise as you’re facing it, so install new impeller with blades bent to turn in that direction.
7. Reinstall water pump cover with 4 bolts.
8. Reinstall belt. Start by putting around right hand wheel, and feed on to bottom of left hand wheel as much as possible. Bump starter on then off quickly to set pulley fully on both wheels.
9. Make sure that the grooves of the two wheels line up exactly. (The large wheel has more grooves so it is possible to misalign.) If the grooves do misalign, use the plastic spatula again to put pressure on the belt while a second person kicks the starter.
10. Open through-hull and run engine to check for function and leaks.
11. Reinstall cover.
 
This is my first year winterizing my R27. It has 200 hrs, so I will change the impeller. In the Yanmar book, it shows a tensioner. Just like I would expect. Any serpentine belt needs a tensioner. Why would you not back off the tensioner, like on a car, with a wrench to remove the belt? Just seems like the wrong way to remove a belt.
 
There are two belts on the BY2 Yanmars. One of them is for the coolant pump and alternator. This is a serpentine routed ribbed belt and has a spring loaded tensioner. You do not remove this belt when changing the impeller.

The second is the raw water pump belt that must be removed to change the impeller. It is stretch fit, no tensioner. It is also routed conventionally, not in a serpentine manner. Technically it is a ribbed belt, not a serpentine belt.

Howard
 
I will try the torx socket idea - never occurred to me that using one of the four offset to turn it would work! I started making an tool to put on a breaker bar that would mate with the hub of the crankshaft, but don't quite have the geometry right.

I'm somewhat chicken to try to get the belt on while my wife hits the starter, with my hands down there. Is there an easy way to insure that the engine doesn't kick on?

I found a set of little tools that are for installing and removing stretch belts, I thought I'd try them for reinstalling the belt on the pulley.

Many thanks for the replies!

Bill
Tugetherness - R29
 
I believe the mechanic used a little set of tools to replace my belt this past year.
 
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