Mercruiser 470 3.7 Harmonic Balancer/Pulley removal

[AgentSBond]

Hi guys, this is my first post here so please be gentle.
I have a Mercruiser 190hp 3.7 (470?)
I'm trying to remove the Harmonic Balancer to get to the Circulation Pump case behind, I've tried using a puller with the three bolts in place and socket torque wrench won't budge. Are there any hidden bolts I cant see to find or another tool I should use? I mean I'm putting all my might into this and there's no movement.

I hope for any advise.
Thanks
Simon

 

[Eric 3.7LX Alpha 1]

Welcome to the forum.
I have the page attached below from service manual #8 that covers removal and installation. I've used a standard harmonic balancer puller in the past without touching my front engine mount.. was not necessary. I do screw the bolt back in some and pull the rotor off against the bolt head rather than pushing on the front of the crank shaft and risk damaging the threads there. What's the reason to get to the circulation water pump?

 

[jhamblett]

Use a impact , it will come. Just did my 470. Standard harmonic balancer....to install I used a 1/2 fine thread rod and nut with the harmonic balancer pushing flywheel back on

 

[AgentSBond]

Welcome to the forum.
I have the page attached below from service manual #8 that covers removal and installation. I've used a standard harmonic balancer puller in the past without touching my front engine mount.. was not necessary. I do screw the bolt back in some and pull the rotor off against the bolt head rather than pushing on the front of the crank shaft and risk damaging the threads there. What's the reason to get to the circulation water pump?

Hi Eric,
That's the exact manual page I was searching for thank you.
I guess I need to persevere. The reason I need to get to the circulation pump is that I have coolant pouring into my oil pan which I've ascertained it could be the timing chain cover seal (gasket). So I'm going to replace the gaskets which look to be bodged with gasket maker at the moment. I'm currently flushing the oil to get the water/coolant mix out. Thanks for your message, it shows me that i'm on the right track

One thing I cant work out, it why the weep hole on the circulation pump always has a bolt in it. I thought the purpose of the weep hole was to check for leaks, is it bolted to use as a drain off?

Cheers
Si

 

[AgentSBond]

Use a impact , it will come. Just did my 470. Standard harmonic balancer....to install I used a 1/2 fine thread rod and nut with the harmonic balancer pushing flywheel back on

Thanks for that Jhamblett.. I'll get the impact driver out the box
Si

 

[Eric 3.7LX Alpha 1]

Hi Eric,
That's the exact manual page I was searching for thank you.
I guess I need to persevere. The reason I need to get to the circulation pump is that I have coolant pouring into my oil pan which I've ascertained it could be the timing chain cover seal (gasket). So I'm going to replace the gaskets which look to be bodged with gasket maker at the moment. I'm currently flushing the oil to get the water/coolant mix out. Thanks for your message, it shows me that i'm on the right track

One thing I cant work out, it why the weep hole on the circulation pump always has a bolt in it. I thought the purpose of the weep hole was to check for leaks, is it bolted to use as a drain off?

Cheers
Si

Your weep hole should be open like in this picture. If there is a plug in it, remove it, poke the hole with a wire to make sure the passage way is not blocked and confirm whether or not the seals are worn before you get into a job you may not have to do. Has the motor ran hot at all? Overheating these motors can easily blow the head gasket and can also put water on top of the pistons and in the crankcase. Did you check for water on top of any of the pistons by removing the plugs and cranking the engine over, see if any water comes out the plug hole? Read this write up about the 470 weep hole leak if you haven't seen it yet. It explains the job: https://www.sterndrives.com/470information/470coolantleakrepair.html

See the attached pdf file:

 

[AgentSBond]

Your weep hole should be open like in this picture. If there is a plug in it, remove it, poke the hole with a wire to make sure the passage way is not blocked and confirm whether or not the seals are worn before you get into a job you may not have to do. Has the motor ran hot at all? Overheating these motors can easily blow the head gasket and can also put water on top of the pistons and in the crankcase. Did you check for water on top of any of the pistons by removing the plugs and cranking the engine over, see if any water comes out the plug hole? Read this write up about the 470 weep hole leak if you haven't seen it yet. It explains the job: https://www.sterndrives.com/470information/470coolantleakrepair.html

See the attached pdf file:

Bit of an odd scenario, but a mate of mine who is an engineer but not familiar with Mercruiser's serviced my sterns, and when testing the portside engine, he put a pressure hose in the water inlet with sterns off without cranking the engine. Flooded the engine with water and then cranked it with sparks removed, breaking my Starter motor nose and pressure popped the lid off the coolant and water came out the spark plug hole #3 which I've been told is a sacrificial cylinder that will allow water through in extreme overpressure situations such as hydrolock, so not to crack or blow gaskets etc. but i do now have coolant in my oil, which I'm not ready to remove the head yet until I've changed the circulation pump gaskets. After all that happened I found the bolts were loose on the timing cover and gasket was wet.

Thanks for the image that wasnt what I thought was the weephole. I'll get to the boat tonight and check now that I've seen that. This is the model timing cover I have:

Cheers,
Si

 

[AgentSBond]

I think you're right I'll check for the weep hole later and see if it's blocked up with gunk. The engine cranks nicely now I've changed the starter motor.. and I've checked for water in the spark plugs after cranking and there's no water in them now but the boat is now on the mooring so I'm reluctant to crank now incase it is the head gasket, until I've changed the timing/pump gaskets and got the contaminated oil looking clean first.

 

[Tonyboyscarbz]

Sorry to revive an old thread but curious how you got the harmonic balancer back on the cam shaft? Did you use a tool or the old wood and hammer method?

 

[jhamblett]

Crank shaft and....its a threaded rod(forgot pitch) with harmonic balancer tool and some sockets for Spacing. Works great

 

[Tonyboyscarbz]

Crank shaft and....its a threaded rod(forgot pitch) with harmonic balancer tool and some sockets for Spacing. Works great

Sorry yes, crank shaft. Thanks for sharing. Is this a home made solution or the appropriate tool designed for this?

 

[achris]

Sorry guys. Old thread (more than 90 days), please start a new thread of your own.