Random act of kindness...helping someone with 470 engine

[tmh]

OK, I am asking this question trying to help a person I don't even know who posted issues with his/her (I'll go with "her" so I feel even better helping) boat. I exchanged emails and feel she got screwed on a purchase so trying to help out.

Condensed story, bought a 1979 Sea Ray 192 (17.5') boat from marina because it was in great shape. Finds out the 470 engine is overheating, losing coolant (maybe from blowing off cap). Marina charges $300 to replace the impeller, doesn't fix problem. blah, blah, blah....

I only know what I've read on these engines so i DO know they have lots of expensive issues. Also could be impeller pieces stuck, etc. If I recall, a smaller heat exchanger was also used that far back.

She loves the boat ad has access to a somewhat newer (no details) 120 hp 4-cyl merc with outdrive. I am wondering if she's better off swapping in the "regular" 4-cyl engine and avoiding current and future 470 issues. Fresh water lake only so no salt issues.

1. CAN a 120 be straight swapped for the 470?

2. Could the existing drive be used? mods needed?

3. Would it need hull mods (transom), etc. to use 120 engine with it's drive (alpha one I presume)?

4. Is it a lost cause? I KNOW the boat really has min. value, but she owns it now and maybe can salvage the deal somewhat. maybe not.

Any other input helpful. If WE can get her up and going I'll report back with the success of iBoats forum's random act of kindness.....

 

[bruceb58]

Re: Random act of kindness...helping someone with 470 engine

I will help you with the first question. Don't bother with a 4 cylinder. The boat would be dreadfully underpowered.

 

[stonyloam]

Re: Random act of kindness...helping someone with 470 engine

You do need the 4" heat exchanger, but before you spend $ on that you have to determine the basic health of the engine, especially the head/head gasket. You need to do a engine compression test and a cooling system pressure test. You can borrow the tools from Autozone for free. The tests are easy ( if you can change sparkplugs you can do them). If the compression is low (especially 3 & 4) you may need a gasket/valve job. Let us know what you come up with. Loosing coolant is not a good sign. Seems like the marina should have some obligation to help here. Good luck

 

[tmh]

Re: Random act of kindness...helping someone with 470 engine

Thanks so far. Anyone know the technical answer to the engine swap questions? WOULD it fit/hook up? It's not a very big boat, just over 17' so I think a 120 hp 4-cyl would be OK for someone not wanting to win races or slalom ski.

 

[Don S]

Re: Random act of kindness...helping someone with 470 engine

You would have to find the proper exhaust Y for the 120. and a gear ratio change in the drive would be a must going to the smaller engine. After that, who knows, different years had different small changes. There are always little "Gotchas" in swaps like that.

 

[tmh]

Re: Random act of kindness...helping someone with 470 engine

Thanks, Don. Maybe too many "gotchas" to bother with, IMO.