Yanmar 3ym30 belt tension

[choppy]

Greetings all,
The impeller belt on pump housing once I have correct tension looks ok but rapidly starts to pivot - just will not lock (Hence belt degrades fast)
Tightened to the point where must be getting close to stripping.
Taken a look at the blow up parts catalog and all looks to be present & in place
Any ideas or experience please ?
Cheers

 

[RichardS]

The water pump belts on both my 3YM30s are slackened off as far as the slider will go, so that the belts are extremely loose. This means that the bearings in the pumps and the belts themselves will probably last forever. It's a very low stress job turning the pump and not comparable to an alternator drive belt.

How tight are you trying to do the belt is the obvious question? If not too tight, then maybe the thread in the tensioner nut is already partially stripped or you need to use a spring/locking washer or nyloc?

Richard

 

[vyv_cox]

Greetings all,
The impeller belt on pump housing once I have correct tension looks ok but rapidly starts to pivot - just will not lock (Hence belt degrades fast)
Tightened to the point where must be getting close to stripping.
Taken a look at the blow up parts catalog and all looks to be present & in place
Any ideas or experience please ?
Cheers

Are the two pulleys in line correctly? Not got a washer the wrong side to misalign the pump? As Richard says, the pump belt does not need to be very tight.

 

[[3889]]

Greetings all,
The impeller belt on pump housing once I have correct tension looks ok but rapidly starts to pivot - just will not lock (Hence belt degrades fast)
Tightened to the point where must be getting close to stripping.
Taken a look at the blow up parts catalog and all looks to be present & in place
Any ideas or experience please ?
Cheers

Have you had a leak in the impeller seal? This will damage the shaft bearings and make the pulley stiff. Whizz off belt and see if you can turn the impeller pulley by hand.