AQ125 Volvo Timing belt slips

[Jimleopold]

I opened season and found timing belt had slipped and tore teeth badly. I replaced belt with new. Engine fired right up. Next day I realized belt had slipped. I re-installed it and made sure tensioner was tight. It seemed to run fine with muffs. Last night I put it in the water. It was very difficult to start. Once started I found it had no power and was back firing. I did a quick look at the belt and could see it had slipped. Arrrgh!
Is there anything that could be causing it to slip? The tensioner looks fine.
Thx

 

[Don S]

Re: AQ125 Volvo Timing belt slips

Rusty pulleys. Just like a grinding wheel on the belts.

 

[Mullin]

Re: AQ125 Volvo Timing belt slips

Yeah rust will mess things up. Not only the damage to the belt but also filling in the grooves with rust leaves less for the belt to hold onto, making it easier to slip. You could probably wire wheel and scrape the pulleys into pretty good condition though.

Also the timing belt tensioner spring is probably almost 30 years old. I followed the books guide to installing the belt (included tightening and then running and then re-tightening again, IIRC) but I helped out the tensioner pulley spring with a little push while re-tightening the pulley bolt. That seemed to help and it's held for a while, into the third season now.

 

[Jimleopold]

Re: AQ125 Volvo Timing belt slips

Thx guys. No rust at all. I also used a large screw driver to push tensioner to the right as i tightened it. It seems to slip on the cam. I cant imagine how cam could lock up. I will try again and push really hard. Had this boat 10 years and never slipped before.

 

[ajax5240]

Re: AQ125 Volvo Timing belt slips

I'd try and find a new spring for the tensioner. Should be cheap insurance.