Flying Pulley

[Sandero]

I was motor sailing and the wind picked up and I turned the engine off. I went below and smelled some antifreeze. Checked the engine and the pulley on the FW cooling pump had come off, with it the belt and the engine had just over heated and lost less than a quart of coolant.

I retrieved the pulley from below the engine, pushed it on and the hit it with a mallet to get it to align with the flywheel pulley. Seemed tight and pump rotated with no friction. Put the belt on, tensioned it, topped up the coolant and ran the engine and she ran fine at correct temp. Cooled down very quickly.

My questions are:

Is this a normal way for a pulley to be attached... no set set screw or other means of securing. I suppose if the shaft is tappered a bit and it might be tight enough ...but seems odd.

Should I change the belt?

What caused this... after 24 years and 4200 hrs?

Volvo Penta MD17D w/ fresh water cooling add on kit.

[mesquaukee]

It is not unusual to have pulleys press fitted onto a shaft. I had a similar occurance on an Volvo car years and years ago. It slid off when it was 40 below in Manitoba.
Press fit pulleys and bearings was and is typically done on a lot of assembleys.
Why it should suddenly slid off who knows. You might want to replace the assembly. In a pinch to secure it a hole can be drilled and tapped for a set screw.

[GordMay]

Does your CW Circulation Pump look like this?
➥ CIRCULATION PUMP WITH INSTALLATION COMPONENTS - Volvo Penta

If so, it has a “circlip” locking ring (#9), which fits into the shaft groove.

Some Volvo Penta Manuals, as posted here
http://www.cruisersforum.com/forums/...ls-8758-3.html

Goto:
➥ http://www.bluemoment.com/manuals/Vo...0-20-30-40.pdf

or
➥ Volvo Penta

[Sandero]

Here is a pic taken after I resembled the pulley on the pump. It's run now several hours (4) and all seems OK.

Bizarre since I don't know why it happened... after 24 yrs...

[mesquaukee]

Take a scratch awl or large needle amd scratch around the end of the shaft. You should find a goove about 1/16" wide and 1/8" deep that's full of rust. It may be very hard to find as when the wheel slid off it would "polish" the rust. If not the wheel (pulley)may have to be pressed on further.
Before you hammered the wheel on did you notice a shoulder on the shaft to limit how far the wheel could be pressed on. Was there a circlip?

It is not reccomended practise to hammer a wheel on. The bearings in a water pump are small and can be damaged with heavy hammering. This can lead to failure as small dents or flat spot occure on the bearing race and/or on the balls or rollers.

[Sandero]

I tapped the pulley with a mallet and very didn't pound it very hard. I'll look for a groove, but didn't notice one, nor see evidence of one. It might have corroded off, if it was there a while ago and only now for some unexplained reason the pulley worked its way off.

I'll measure the shaft and look for a replacement circlip and scratch around for the groove.

I couldn't find an exploded diagram of the assembly so I am not certain about the circlip... but it makes sense.

The pulley is aligned as best I can tell and I don't want to be pounding the thing for fear of damaging it.

Thanks to everyone for their help

[boden36]

I have a workshop manual or one of these motors on the Australian eBay at the moment. Regards, Richard.