4.3L OMC sterndrive eating belts

[mikelosey]

I have a 95 chris craft 18 c0ncept with a 4.3L OMC sterndrive. IN the past 2 months I have replaced all of the belts multiple times. the alternator belt belt is especiaaly bothersome because all of the belts have to come off to replace this one. I have replaced this one at least 3 times in the last 2 months. I get the belts tight and after a few minutes of running they are loose again. can anyone tell me what is going on?

 

[Bifflefan]

Re: 4.3L OMC sterndrive eating belts

are the pullies bent? or have some kind of corosion in them?

As for the getting loose, try using a center punch and putting a couple dings in the mount where the 2 surfaces meet. that should give it some traction and not let them slip.

 

[cr2k]

Re: 4.3L OMC sterndrive eating belts

You can over tighten belts and have them come off too. Also over tightening will eat the bearings in your...Circulation pump, alternator, PS pump, etc.

Make sure the pulleys are clean and not worn, the sides should be straight not rippled or warn. The belt should NOT ride on the bottom of the groove.

Sounds like the pulleys could be rough, rusted or just bad and wearing the belt so it rides lower and becomes loose.

 

[River's Revenge]

Re: 4.3L OMC sterndrive eating belts

Belts will generally fail due to a few things. 1. Miss alignment= if the pulleys are not lined up, tension, heat, wear, all start to add up and finally failure occurs.
2. The wrong belt. some belts have more of a "V" then others. or like a serp. grooves. If the pulley is not cut to the right belt or vice versa well, you once again have unwanted tension, heat, wear, slipage, ect.
3. Also tightness, some systems need a real tight belt, others not so much. Generally by taking your thumb and pressing on the belt you should have somewhere near an inch deflection. If you get slippage just tighten slightly.

My best guess... is alignment. but check the book on type and legth of belt. you might be using the wrong belt.

 

[mikelosey]

Re: 4.3L OMC sterndrive eating belts

All of the pulleys are rusty and show corrosion> i dont think i over tightened the belts>i bought the boat from someone who only ran the boat in saltwater> i run it in both

 

[Bifflefan]

Re: 4.3L OMC sterndrive eating belts

All of the pulleys are rusty and show corrosion>

Well there's your problem......

when the belts are tight, find the longest space between 2 pullies and push on the belt with your thumb. It should deflect about the thickness of your thumb with light to moderate pressure.
In other words, the belt only needs to be tight enough to keep the pullies from slipping under most conditions.

A belt that goes 1/2 way around a pully does not need to be as tight as one that goes 1/4 way around the pully.

That should be enough to add to your confusion.

 

[cr2k]

Re: 4.3L OMC sterndrive eating belts

Rusty, corroded pulleys will wear the sides of the belt and it will run lower in the pulley and get loose. Clean the rust/corrosion and try again.

 

[mikelosey]

Re: 4.3L OMC sterndrive eating belts

I have done a thorough inspection on the pulleys and the circulation pump pulley is rusted all of the way thru in one spot for about 1 1/2 inches. I ordered a new pulley and it came in but it is like 1/2 the diameter of the one that is on there and 1/2 inch hole vs 5/8. However the other holes match up perfectly. I think the one on there was changed out by the former owner to put a less expensive automotive water pump on there. Does anyone have any suggestions? I could punch out the center hole of the new pulley to meet the 5/8 shaft size. Or I could get another water pump, marine version, and replace that as well. The one on there is working fine and I hate to replace a part i dont need to.