belt tension

rasbury

I'm looking at belt tension gauges and see that I need to have the tension amount to get the proper gauge....350 mpi motor, 2005, anyone have that number?

frenchship

Here are the Infos two way to adjust the belt with the gauge $$$$$$ or by hand

rasbury

Can't really read on my phone and surprised there is little info on line. Gauges run from 15 buck to 115 bucks, or by hand about 1/4 inch play. I'm concerned to have it to tight and mess up the bearings in all the stuff that spins, perhaps I'm over thinking this one.

Handymans342

The belt will stretch before the bearings go out

planesailing

I have never used a tensioner gauge when changing or adjusting the belt. I just tighten it by feel and I just make sure it doesn't turn more than 90 degrees on the longest stretch on top. Always been fine with that method.

frenchship

 Raz,
It is not 1/4 inch but 1/2  inch 

rasbury

1/2 "? That sounds like a lot!

rasbury

Water pump does not have any sealer on it, just the rubber gasket ? Can't remember!

skennelly

Yeah I've always heard and followed the 1/4 rule.  1/2 sounds like it would be too sloppy.

frenchship

That is what is recommended by Mercruiser service manual as stated in the picture above.But you do whatever you think is best.

rasbury

How about the pump, dealer or just the rubber gasket?

skennelly

@frenchship I stand corrected.  1/2 seems slot though.

Black_Diamond

Depending on the belt, it will not stretch. You can easily overload the bearings on driven equipment. Best way to tension is with an ultrasonic meter. Just saying. 

rasbury

I have looked on line and they seem to be pretty sparse! I will tell you, the belt on there is not a mercruiser one- I did have a raw water pump failure couple years back at the ramp but thought I just broke a belt. I went around the corner to the auto parts store and found one of suitable length. I'm guessing that one was able to stretch! Also, I was spraying out the bilge from my waste tank disaster and although I was trying not to get the motor wet, I'm sure I got some water on the belt...so combination of wet, a little stretch to it maybe was all it needed to start slipping.  I sure did not want to take any chances of adjusting the belt (which I did not think of anyway) and pushing impeller through the rest of the cooling system so I did the right thing and took it home. I thought the gauge would be a fairly common item but I guess most motors today and the spring self adjusting tensioners. Would still think they would need to be checked/verified but none of the local auto parts stores seem to have them. Nor, with a quick google get the tension it was supposed to be either. Now that I'm off my phone and on the computer, I see above where it says to do aprx. 1/2" and then use gauge-but it does not say what the correct tension is, they can't all be the same? I see those gauges for sale anywhere from 50 to 100 bucks. Sounds like a good safe investment. I have a manual I believe on my desk top, perhaps that will have the tension amount. 

frenchship

Ras
You are making something easy complicated, just follow the instruction in the service manual
1/2 inch deflection at the longest stretch of the belt And keep the 50$ to 100$ for gaz

Cableguy Greg

I agree with @frenchship , adjust with a 1/2" deflection and save the money for gas. The raw water pump only has the rubber gasket.

rasbury

10-4, thanks for all of the input. Don't think I will get it put back together tonight since the temps may be below 75 by the time I get home and I can't do this stuff in those conditions!

Cableguy Greg

rasbury said:

10-4, thanks for all of the input. Don't think I will get it put back together tonight since the temps may be below 75 by the time I get home and I can't do this stuff in those conditions!

Say what?????? You can't work when temps are below 75? Florida weather must REALLY thin the blood.

rasbury

lol....have to poke the bear

reneechris14

Your fingers must be cold from the beer. 

rasbury

10-4 @reneechris14  !

rasbury

Now I remember why I needed a gasket material...i am using a modified impeller with shims - the large shim on the cover requires a gasket material , shim is stainless. Could not find any instruction or recommends on their web site, what should I use? There are so many types and they all seem to say they do the same job...i don't think the impeller was broken in operation but from me yanking on it with pliers.....i have an extra one that looks like a match in height and was pleased to see the shims showed little wear.