Anyone know the length of the serpentine belt for a 97 5.7L Alpha - serial= 0K026165 ? I'm seeing around 86 inches. I can't take the old belt off to measure because it was destroyed and discarded by PO.

You take a string and follow it around your belt exactly then cut the string - lay the string out perfectly and measure that. Also Mercruiser lists their belts in mm lengths and so do a lot of belt manu's like Gates, Dayco, Goodyear and so on.

Question on the same vane..when doing the measurement can a alternate belt be used if it say 1/8 to 1/2 shorter than the oem belt. Is there a allowable tolerance?

The new mercruiser belt for that application comes with a new ps pulley. The old pulley was composite. New one is metal and a little different size so old belt number has veen change.

Yes, there can be a small variance...that slack will be taken up by the tensioner pulley; as long as it isn't maxed out.

Any idea on why they switched the PS pulley?

Probably so they can charge more for the kit and discontinue the old belt...lol... Tap on yours and see if it is composite... IE Plastic....lol... I tried matching up the old belt at autozone and the autozone belt was just not as good. We take our boat to the Bahamas so I wanted the best I could get so I bought the merc one that came with the new pulley. I rented the pulley puller from anvanced auto parts. Took about 20 min to pull and replace with ps pump still mounted to the motor.I am sure it is my imagination but boat steering seems easier now.

Chris

No the plastic composite pully's the bearings wore out faster as the composite surroundings are not a stable as the metal ones for the bearing support especially a motor turning 4 to 5 k rpms all the darn time. Man we have changed a ton of the Volvo composite pully's as well, a very common problem.

Now I will ask how do you think we find a bad bearing(s) in the pully's as the motor is running - sometimes it can sound like its coming from the valve train. Some are slight tick noises to louder more constant noises.. Also some are almost locked up after you pull the belt to check them.

My pulley is composite, but spins easy. Back to the belt: I got the 86-inch measurement using the string method, I was just looking to confirm if anyone could find or knew the proper size. Any confirmations on that length?

Do not put Autzone or What ever generic discount auto crap oarts store junk belts on whatever you do . If you can't buy a Merc belt buy a Gates brand at the very least.

I know I answered in this post before to help and I have to say wow you posted your model and serial # along with telling what outdrive you had. Unreal. So that makes it easy for someone who sells marine parts and or works on boats not a guessing game as to what you really have so you can get the correct parts and the correct service procedures for your app.

See here is the fact on your motor if you had the alpha outdrive your belt is one length and different part # than if you had a bravo outdrive. The bravo outdrive sea water pump makes the belt longer. No guessing game as you gave out all the info needed.

YOUR BELT SIZE IS 2197 mm. Like I said they go by mm not inches as that goes the same for Gates, Dayco, Merc, Volvo, OMC and so on. You can convert the mm into inches if you need to. Thank you for making this so easy.