Replacing belts on a mercruiser

[pschauss]

The alternator belt on my port engine still slips even after I tightened it, so I am assuming that I need to replace it. Of course, I need to remove the one for the raw water pump in order to get at it, so I will be replacing both. The alternator belt adjusts just like one on a car, so that will be straight forward. Is there any trick to replacing/adjusting the raw water pump belt?

Is there anything special about these belts or can I just get one from an auto parts store?

Thanks,

[Donmystic1]

If you can reach down to the raw water pump with your camera phone, take several Picts at all angles. You will see where the adjustment can be made.

Good luck

[mike ohlstein]

Belts are belts. Nothing special.

The by slipping you mean squeaking, try a little talcum powder on them. Stops the squeal.

[Bruce]

While Mike as a whole is correct about belts being belts, there are subtle differences that can make a difference that some lazy drop out at an auto parts store, even NAPA these days, will create an issue.

First and foremost belt wear is normal. If there is excessive belt dust over the front of the engine, check for pulley alignment and rust in the v grooves. Those two will chew up belts quickly.

Belts come in different widths and angles. While they look close, most everything today are metric measurements which don't always cross over to matching specs. Too narrow an angle and the belt sits low in the grooves and will wear. Too wide and it will sit high in the groove wearing it premature. The same goes for width.

Find an auto parts store thats been around for a while and has someone older that 45 working in it. If you have a belt number and make, get the same thing. It doesn't always cross over proper to a different manufacture.

New belts will stretch some. Don't use a 5' pry bar to tighten. Use a belt tensioner if you can or tighten just enough to keep from slipping.

[pschauss]

Bruce,

Any suggestions for a tool to adjust the belts? I remember that J. C. Whitney used to sell something that pushed against the two pulleys and allowed you to adjust the tension by turning a nut on the threaded part. Most everything that shows up on Google seems to be designed for adjusting serpentine belts.

Thanks,

[Stephan]

Don't use a 5' pry bar to tighten...

I previously used a 3' pry bar. I now use an Irwin quick grip clamp https://www.lowes.com/pd/IRWIN-QUICK-GR ... 1000235515. The fixed end on the clamp can be swapped to the opposite end to make a spreader.
I tighten the top bolt (this is the pivot on my 454's alternators) fairly tight, then tension with the spreader between the main pulley and the alternator housing.
I use the same spreader for the raw water pump to get started however my raw water pump brackets were modified by welding a nut to the base and running an adjusting bolt through it to help hold tension on the water pump while I tighten the two water pump base bolts down. This shows the bracket without the tensioner modification.
I hope this helps-
Stephan

[MarkS]

NAPA has a line of belts called “Gold.” They are a bit more expensive and seem to last longer. I have not noticed much of a difference in automotive belts but on the snowmobile they made a huge difference! I just use them on everything and have not been disappointed. Just my $.02