Timing belt advise - F115 EFI

tomyoud · 13 May 2019, 11:17

Hi all.

Bit of advise from anyone - I've changed the timing belt on our Mariner F115 EFI 4 stroke.

I've followed everything using the workshop manual down to a T. I've turned the engine over so many times by hand to make sure the marks still line up...and they do.

When the engine is running, the tensioned side of the belt (opposite the tensioner) has a little bit of vibration (if that's the word) between the intake cam and the crankshaft.

I stopped the engine and checked all the marks and it's all still lining up, when I turn the engine by hand and push gently on the belt it's not slack at all.

Is this normal? I've never ran the engine with the flywheel cover off before so I never noticed it.

beamishken · 13 May 2019, 16:09

Assuming the tension is correct then your probably fine, is the tensioner spring loaded or locked off once tension is on the belt? Did you turn the engine to put all the slack at the tensioner side before locking off the tensioner? Some belts with long runs will flap a little but as long as its correctly tensioned and not hitting anything then I'd stop worrying

tomyoud · 13 May 2019, 16:24

Thanks for the reply - so I made sure all the slack was on the tensioner side and inserted the tensioner and spring. Then let the spring take the load and torqued the tensioner down to 40NM. Once I did that, I turned the engine over by hand.

Is it worth me backing off the bolt again and letting it settle on the spring again?

To be honest it is a fairly long run from the intake cam to the crankshaft and it's not touching/hitting anything....maybe I'm over thinking it.

beamishken · 13 May 2019, 16:42

Wouldnt harm to recheck now its been run tbh

tomyoud · 13 May 2019, 16:46

Great, I'll give it a go at the weekend and just leave it there.

Thanks again

Fenlander · 13 May 2019, 17:25

As advice above just allow the spring to re-tension at the correct place in the firing cycle as per the advice you followed to do the job.

Many car belts are set up for tension then the engine turned two full turns and the tensioner allowed a second chance to settle before finally tightening.

As you say above you'd never seen it run with the cover off before. Rarely do folks get to see a car belt mid section... some flap alarmingly even when set 100% correctly.

tomyoud · 14 May 2019, 08:13

Thanks Fenlander, I'll give that a go this weekend.