7.4l Throwing Belts..... Help.....

[sailsmanship]

Have a 94, 7.4L Mercruiser that has stripped teeth and broke the fresh water/fuel pump belt three times in the last 18 months. Never the other two belts. Had the alignment checked, tensioner replaced, and water pump re-built all in that time frame, still ruins the belts. Since this is the only belt that serpintines around pulleys, could this be a heat related problem do to excessive flexing. The belts that stripped teeth had no glazing on the back, but did have a few cracks in the tooth gullets around the belt, even though they average six months old. I purchased the Gates green line which is supposed to be a premium belt, No luck. Is there a better one out there?. This happens at cruising RPM. I rarely jump on it hard.

 

[johnkc]

Re: 7.4l Throwing Belts..... Help.....

i replaced one of these belts once with a non oem belt and it shredded in about 15 hrs. put a mercruiser belt on and it has been 2 years now on this belt .

 

[Elk Chaser]

Re: 7.4l Throwing Belts..... Help.....

The water pump was rebuilt, was the pulley replaced or even checked?<br /><br />I've seen pulleys (sheaves technically) that had small defects that would eat belts no matter what belt you bought. Granted, the alignment is just as important but you could be off slightly and not eat belts. The other thing to look at is the the use of the proper size belt that fits in the groove of the sheave (all sheaves) and has good clean contact along the entire side of the belt (cross sectionally) on both sides of the V and it should not sit but slightly outside (or above) the sheave. <br /><br />Only close examination will tell you if the sheaves have a problem, all the pulleys in that serpentine need to be checked while spinning slow. Even just a slight change in the width of the groove, a slight wobble or even a slight burr or rough spot in the groove can cause what you described. <br /><br />I do not think it is a belt quality problem at all, if everything is lined up and in good condition then the belt should last many hours of operation at any RPM as they were all designed to do this.<br /><br />Personally I never liked the cogged belts and stay with the smooth. Not sure what the Gates green line is but the last belts I put on my 7.4L were purchased at Schucks and they were the top of the line with slight cogs on the outside (top) edge to increase the life of the belt.

 

[sailsmanship]

Re: 7.4l Throwing Belts..... Help.....

I talked to our local merc. distributor and he said when he orders merc. belts from merc they come in with gm automotive part#'s on them. Is there a difference in marine? I am willing to pay premimum for anything that might help... And, will solid belts flex enough around a idler/tensioiner without creating weakness?

 

[KaGee]

Re: 7.4l Throwing Belts..... Help.....

Originally posted by myklskc1:<br /> I talked to our local merc. distributor and he said when he orders merc. belts from merc they come in with gm automotive part#'s on them. Is there a difference in marine?

Not if it has a GM part #.<br /><br />But someone may want to check the "Regulations". (inside joke here)

 

[Elk Chaser]

Re: 7.4l Throwing Belts..... Help.....

The solid belts should be fine as long as everything is in good order as stated above. That I am aware of there is no special design for Marine Belts..... Bt then again every time I say that someone tells me otherwise.<br /><br />KaGee