Changing timing belt on 1972 Mercury 1150...

[DVTO2]

So when removing my carbs to clean them I noticed the timing belt was cracked in numerous places and ordered a new belt along with the carb parts. I got the flywheel off and the top of the distributor gear for the belt but I am unsure of the best way to get the belt off and then back on the main part of the motor. There is a curved plate on top of the timing belt that blocks my pulling it off, though it slides a bit and I can kind of start one side off, but it doesn't slide as much to the other side. Do I need to further disassemble the top of the drive shaft and is it tricky to do? From looking at my manual it seems like I might need a special tool.

The pen is pointing to the plate I am referring to which blocks the belt from being removed. The part I am wondering if I have to remove is above the plate.

 

[Bob_VT]

Re: Changing timing belt on 1972 Mercury 1150...

So when removing my carbs to clean them I noticed the timing belt was cracked in numerous places and ordered a new belt along with the carb parts. I got the flywheel off and the top of the distributor gear for the belt but I am unsure of the best way to get the belt off and then back on the main part of the motor. There is a curved plate on top of the timing belt that blocks my pulling it off, though it slides a bit and I can kind of start one side off, but it doesn't slide as much to the other side. Do I need to further disassemble the top of the drive shaft and is it tricky to do? From looking at my manual it seems like I might need a special tool.
View attachment 163754
The pen is pointing to the plate I am referring to which blocks the belt from being removed. The part I am wondering if I have to remove is above the plate.

Yup you have to go deeper I have done it with a puller and air tools. It's just another layer. I do not know if Mercury had a special tool?

 

[DVTO2]

Re: Changing timing belt on 1972 Mercury 1150...

Yup you have to go deeper I have done it with a puller and air tools. It's just another layer. I do not know if Mercury had a special tool?

Could you give a little more detail about the steps.

 

[DVTO2]

Re: Changing timing belt on 1972 Mercury 1150...

And what's a puller?

 

[merc850]

Re: Changing timing belt on 1972 Mercury 1150...

You have to undo the large nut that holds the flywheel hub to the crankshaft then use a puller to pull the hub off (there is a special puller that threads into the threads in the hub and they're available on ebay http://www.ebay.com/itm/FLYWHEEL-PU..._Accessories_Gear&hash=item3ca130898d&vxp=mtr). The pulley for the timing belt is attached to the hub and will come off with it, that will allow you to remove the belt and replace it. Since you have taken the flywheel apart you will need instructions on how to assemble it because the timing marks are on it.

 

[DVTO2]

Re: Changing timing belt on 1972 Mercury 1150...

You have to undo the large nut that holds the flywheel hub to the crankshaft then use a puller to pull the hub off (there is a special puller that threads into the threads in the hub and they're available on ebay http://www.ebay.com/itm/FLYWHEEL-PU..._Accessories_Gear&hash=item3ca130898d&vxp=mtr). The pulley for the timing belt is attached to the hub and will come off with it, that will allow you to remove the belt and replace it. Since you have taken the flywheel apart you will need instructions on how to assemble it because the timing marks are on it.

Would this work?

http://www.amazon.com/Mercury-Marin...TF8&colid=2HQPGOHJZUTI7&coliid=I275H5U4KKC7Z7

 

[merc850]

Re: Changing timing belt on 1972 Mercury 1150...

Yes, make sure the little cap is greased and on top of the crankshaft end and that the puller is threaded all the way into the hub.

 

[DVTO2]

Re: Changing timing belt on 1972 Mercury 1150...

So I got a tool and reattached the flywheel - it was marked so I think I got it on correctly. I could use some help with the steps on this..

1) it looks like I need to block the flywheel with something to get the nut off - any suggestions?
2) remove the nut.
3) I am not sure what to do from here.

 

[merc850]

Re: Changing timing belt on 1972 Mercury 1150...

Torque those flywheel bolts to 20 ft.lbs. and use blue Loctite on the threads.
1: Wedge a screwdriver upright between the starter drive and the FW to stop it from turning while you undo the nut.
3: Thread the puller into the FW with the little cap on the end, turn the center bolt down until FW pops off.
Remove the timing belt from the distributor pulley first then pull FW off.

 

[DVTO2]

Re: Changing timing belt on 1972 Mercury 1150...

OK, Thanks, I'll give it a go.

 

[DVTO2]

Re: Changing timing belt on 1972 Mercury 1150...

Torque those flywheel bolts to 20 ft.lbs. and use blue Loctite on the threads.
1: Wedge a screwdriver upright between the starter drive and the FW to stop it from turning while you undo the nut.
3: Thread the puller into the FW with the little cap on the end, turn the center bolt down until FW pops off.
Remove the timing belt from the distributor pulley first then pull FW off.

Are there any other suggestions for how to hold the flywheel, because:
1) I already have the distributor off because I am cleaning the carbs (and waiting for parts) and the distributer isn't that easy to get back in (the nut under the flywheel is giving me trouble), and
2) I am a little worried about what the pressure of removing the flywheel will do to the starter.

 

[Chris1956]

Re: Changing timing belt on 1972 Mercury 1150...

I always stuck a screwdriver into the ring gear and found part of the block to stick the end of the screwdriver into. I would be afraid of bending the Bendix on the starter. A strap wrench around the flywheel may work as well. I have used a stillson wrench on pulleys in the past, with good results.

The flywheel and crankshaft have a W-shaped groove rather than a traditional woodruff key. Put some penetrating oil on the flywheel-to-crankshaft joint. You can probably use a harmonic balancer puller to pull the flywheel. You would need some long 5/16" fine thread bolts and nuts to attach it to the flywheel.

 

[DVTO2]

Re: Changing timing belt on 1972 Mercury 1150...

I could not find a good place to wedge a screw driver so I tried wrapping a band clamp around the flywheel but it stretched too much. I decided to try a plastic coated cable I had laying around - I think it was something I bought to lock sailboards to the roof rack which I haven't used for a good 25 years. By attaching this to the flywheel and then over the side of the boat to the trailer bracket on hte back of the boat, I was able to torque the nut off.

I will say that it was a bit frustrating trying to get flywheel back on without jamming up the timing belt, but I finally managed. I am just hoping that I kept good enough track of where everything was lined up.

The one question I have is that there was a small tab on the bottom of the distributor pulley that did not line up exactly with the small tab on the distributor IF I lined up the arrow on the distributor pulley with the mark on the flywheel - the tabs were offset just a little bit. But that's what I did - we'll see what happens when I get my carbs put back together.
Thanks for all the help!