Why is my timing belt slipping and smoking?

[PriceTR24speed]

2006 mercury 15hp 4 stroke - Last time out I had a couple of occasions where I thought I smelled rubber burning. The engine was running great and I couldn’t find anything wrong with it but the smell seem to come from the timing belt. What would cause this to happen? Could it just be an old belt or is there an adjustment I need to do, could it be something more major?
Any advice appreciated.

 

[FuzzyGrub]

If it was actually slipping, you would have bent some valves or at a minimum, run like crap. I'd look to see if a tensioner is freezing up or something else is making contact with it. They do have recommended inspection intervals for tensioning, and replacement. I don't know your engines specifics, though.

 

[Crazyboat]

What Fuzzy said, if that belt slips you've got bigger problems then what you are smelling, be thankful it isn't slipping. Get her inspected and quick.

 

[thill]

If it has a tensioner roller, the bearing may be going bad in the roller.
Sorry, not familiar with that motor.

 

[RaisedByWolves]

What Fuzzy said, if that belt slips you've got bigger problems then what you are smelling, be thankful it isn't slipping. Get her inspected and quick.

Depends if it is an interference motor or not.

Some motors you can shred the belt and nothing will hit, others will bend valves if you talk about the belt skipping a tooth.

 

[FuzzyGrub]

Depends if it is an interference motor or not.

Some motors you can shred the belt and nothing will hit, others will bend valves if you talk about the belt skipping a tooth.

Yep, that is why I had: "or at a minimum, run like crap"

Many of the new, mid-size and larger outboards are interferance. Being an older, small displacement, I suspect it is not. If it was mine, I wouldn't want to try to prove it was or wasn't.

 

[LaqueRatt]

If it's anything like the tensioner on a car, it'll get noisy before anything else. If you take the tension off of it and spin it by hand you'll know right away. It should be quiet and not have any slop in it. Just tossing that out there. Pretty much a boat noob, I'm here to learn. Feel free to set me straight if I'm wrong.

 

[Tall Tiller]

I have this same issue, that burning rubber smell, but it's on the wife's vacuum cleaner.
Thankfully my 1975 15hp 2 stroke Evinrude, emits a wonderful smell!

 

[FuzzyGrub]

Nothing like the smell of a two stroke in the morning!