1985 3.7L 470 170hp mercruiser

[OldDiesel]

I picked up this boat off the side of the road with both titles for Free!! The boat is a 7/10 and just needs some new plywood in the floor and some new carpet no biggie. I just did a head gasket and new lifters and push rods and top end gaskets, I also put in a new coil and sparkplugs. I fired the thing up for the first time since installing everything and discovered I have a milkshake machine.. I did some research and discovered that the water pump seals if bad dump coolant directly into the oil pan So I'm in need of a speedi sleeve and some new seals that will hold up!
I am unsure of the best place to order these parts, I would also like to know if there is anything else I need to watch out for? Thanks in advance!

 

[Scott Danforth]

Welcome aboard

Free boats are the most expensive

If the floor is rotten, the stringers and transom long ago rotted

If you didn't use a factory Mercruiser head gasket, that could also be an issue

 

[nola mike]

I picked up this boat off the side of the road with both titles for Free!! The boat is a 7/10 and just needs some new plywood in the floor and some new carpet no biggie. I just did a head gasket and new lifters and push rods and top end gaskets, I also put in a new coil and sparkplugs. I fired the thing up for the first time since installing everything and discovered I have a milkshake machine.. I did some research and discovered that the water pump seals if bad dump coolant directly into the oil pan So I'm in need of a speedi sleeve and some new seals that will hold up!
I am unsure of the best place to order these parts, I would also like to know if there is anything else I need to watch out for? Thanks in advance!

So much more to look out for in a neglected 470. But first is the structure. You need to pull up the floor, check the stringers, and drill some holes in the transom to check for rot before you sink any more money into this thing ...

 

[OldDiesel]

So much more to look out for in a neglected 470. But first is the structure. You need to pull up the floor, check the stringers, and drill some holes in the transom to check for rot before you sink any more money into this thing ...

The whole boat is fiberglass it takes 2 sheets of ply with carpet to renew, it has a gully with a channel for the fuel tank and below storage, it is a mercury mach 1, it is a sporty fishing rig but needs a little love!

 

[Eric 3.7LX Alpha 1]

See if the weep hole is clogged or not that is between the two seals, it should be clear, if the seal is causing your problem, the weep hole will show it. It should drip there to let you know the seal has failed.

These engines will usually blow a head gasket if they overheat at all. After you confirm you're going to get into this, before you dunk it in water, I'd pull the drive off and give it a full water pump kit including the base, not just the impeller in the drive.

If you do have to replace the cam seals and install speedi sleeves, your going to have to separate the bottom of the front cover from the oil pan. The gasket will get damaged. The job calls to drop the oil pan. You may get lucky and the gasket wont get damaged, or you could try to use a new pan gasket and cut out the section under the front cover and piece it in with some sealer in the corners, maybe you'll get lucky. You may be cheaper off getting a whole engine gasket set rather than individual gaskets here or there. It may work out cheaper.

Here is an older post someone wrote about the job on here:

Mercruiser 470 Leaking coolant...why??

I have a 1979 MErcruiser 470, just finished spring commissioning today on this one. Fired right up and ran as it should. Close inspection found coolant leaking from a weep hole?? On the water pump housing. This hole is near the mid/upper left front of the water pump housing looking straight...

forums.iboats.com

and check out this one:

Mercruiser 470 Coolant Leak

 

[Scott Danforth]

The whole boat is fiberglass it takes 2 sheets of ply with carpet to renew, it has a gully with a channel for the fuel tank and below storage, it is a mercury mach 1, it is a sporty fishing rig but needs a little love!

The boats that would have had wood stringers wrapped in fiberglass and woot transom wrapped in fiberglass

That wood rots long before the floor rots

Failure to fixing the rot, the boat will sink

 

[nola mike]

The whole boat is fiberglass

Very, very unlikely. Stringers and transom as well as floor are wood. Not sure if any boat if that era used composite