Mercruiser 485/185HP Questions

[Michael]

I recently received a 23' chris-craft boat free of charge from my uncle. The hull is in great shape however the motor has some issues. The motor sat under the cover with 2 sparkplugs out of the head. The pistons seemed to be seized to the walls of the block. The problem im having is that on the ID plate on the valve cover it says its a Mercuiser 485/185HP . When i try to run the serial number it comes back blank. When i run the CID # or hp it gets confusing. Some searches come back that its a 3.7 liter 170 hp or 190 hp but it clearly says on the ID plate that it is a 185hp. Any idea of who would rebuild this motor ? Or who sells remaned motors like this one ? Also what type of upgrade could i do for this ? I would like to keep this HP because to me this is a big boat and needs a decent motor to push her. I have enclosed a few attachment pics with the ID plate and also showing the block condition after i removed the head. I put marvel oil in thats what u see soaking in the pistons. Any help is greatly appreciated. Thanks  

 

[Michael]

Sorry ID plate pic is upside down !!

[lost a lure]

Try this.

http://www.boats.net/parts/search/Merc2/Mercruiser/485%20-%20%282BBL%20Merc%20224CID%203.7L%20I4%29/5685394%20THRU%206218036%20%281980-1982%29/parts.html

[Michael]

Thank you lost a lure , but after search says serial number not found. Thanks again for the help. 

[L&M]

Check for a metal tag normally near the rear of the engine where it mates to the bell housing.  Often times the # on the valve cover is not the correct one. But being a 3.7/185hp it has to be a mid 80's boat.

[Michael]

Thank You L & M appreciate the help.

[Xxx]

Judging by the starter it appears to be a 470, if you can't find a alternator anywhere, then it's a 470 they have an enclosed alternator. I have a starter & alt rebuild shop, and I was able to see the starter. It appears to be a 4cyl. correct?

[lost a lure]

Thank you lost a lure , but after search says serial number not found. Thanks again for the help. 

That's in your serial number range.

[Michael]

Yes that is correct Pap , it is a 4 cylinder, and thank you again Lost a Lure that is the serial number range for my motor. Thanks Guys.

[Xxx]

I typed in Mercruiser 485 and it came up as a Big 4" 485/470 lots of info about the motor, not the best motor Mercruiser ever used but a buddy of mine has one in his boat and he likes it. Easy on fuel and a great trolling motor he can get under 1mph with it. I guess it's half of a 460 ford engine with a 428cid head. It seems like either you hate them or love them, I would guess the guys that hate them have the well known over heating problems and something about a cam seal that fails and the low out put alternator they have, then there's my buddy who loves the motor. I know he gets way better fuel mileage than I do with a 350 merc. Good luck with it!!

[UpGrady]

I have a pair of 1986 vintage 470's in my Grady... engines have many hours on them trolling and running and outside of some of the well documented issues with the engines I cannot complain about them one bit... www.breezeworks.net is a forum dedicated to 470 enthusiasts that can help answer most any question you may have with this engine. I imagine that Hank (L&M) on here has plenty of experience with them. I use Bill Zahn here on Irondequoit Bay to service mine. There are some parts that are obsoleted and difficult to find now, but work arounds can be found especially with the help of the forum. Remanned engines/blocks are available all over the internet for replacement as well. Reconfiguring your compartment to house a 4.3 V6 would be a good option too and give you much more power for your boat but would be much costlier than dropping in a new/used 185 or 190 version of this engine.

[Raymond Marshall]

Hello, Have acquired a mercruiser 485, and was wondering if any one has experience / knowledge about fitting a velvet drive gear box to one of these. Looking for a bell housing and related bits to make it work.

Cheers

[Bozeman Bob]

7 year old post , you should start a new one with your issue. 

On 9/8/2021 at 9:08 AM, Raymond Marshall said:

Hello, Have acquired a mercruiser 485, and was wondering if any one has experience / knowledge about fitting a velvet drive gear box to one of these. Looking for a bell housing and related bits to make it work.

Cheers