school me merc 470 1977

[magnumdeke]

Looking at a project boat with a merc 470, no nothing about the merc motor, I work as a mechanic so fairly knowledgeable, just no experience with this unit. Give me the low down, motor, charging system, cooling system, lower unit/outdrive. Are these worth working with and what kind of power? Heres the kicker it is in a 26' tinny, sure to underpowered but guessing pretty good on fuel? Schools in help me decide weather to tackle or not!!!!!!!!

 

[Bondo]

Re: school me merc 470 1977

Looking at a project boat with a merc 470, no nothing about the merc motor,

Ayuh,.... Keep lookin',... You Don't want it...
To see Why, search 470 on this forum...

 

[jerryjerry05]

Re: school me merc 470 1977

Some people hate them.I think they are good as long as you maintain them.
They have a ****ty charging system(stator) that you can replace if it goes bad.Lot's have been redone.My brothers boat has the original and it works fine.
The drive is the standard Mercruiser drive as long as you take care of it and keep the oil changed it will last a LONG time.Put in the resivoir system.
They aren't too hard on fuel.
Good power to weight.165-170horses is good for a 4cyl.
The cooling is usually good. In Michigan the water is usually cooler so the heat exchanger is no problem.Some came with a 3" it worked ok.Later they switched to a 4".Much better.
Check the compression and the gear oil and then if they are good.Buy.J

 

[dubs283]

Re: school me merc 470 1977

listen to bond-o

find another project boat

 

[magnumdeke]

Re: school me merc 470 1977

I like the closed cooling system, does the seawater side drain itself? I would like to be able to run in the cold as a duck tender rig and wonder how well the deal with freezing? can drain valve be installed to drain exchanger or will lower freeze. only plus I see to motor is what I read as its weakness, the cooling system

 

[stonyloam]

Re: school me merc 470 1977

If you are a mechanic, I see no reason why you would not be able to get it running and have a good reliable engine. It is hard on head gaskets, especially in the # 3 & 4 holes. You will want to do a compression check, and a cooling system pressure test, to see where it is to start with. A 4 inch heat exchanger is a good idea. The charging system is not the best, but if it is working OK, just keep it and plan on replacing with an alternator kit if it craps out. Just did mine for $299 (a lot less if you can fabricate your own mounts). The waterpump cam seals will leak eventually, but can be replaced in a long afternoon (read this: http://www.sterndrives.com/470information/470coolantleakrepair.html). Now the good stuff: It was designed as a marine engine, so the bottom end is pretty sturdy, light weight and good on gas. As for draining the seawater side, all you have to do is pull the aft plug on the heart exchanger, and check that the power steering cooler drains (if it has one). It seems like it would be pretty easy to put drain valves in both. When I pull my boat for the winter, I just pull the boat drain plug and the exchanger plug and drain it right on the ramp. Takes 5 minutes. My opinion is that if you are comfortable changing a head gasket, then you should be able to handle a 470. Just go in with your eyes open. Good luck.

 

[magnumdeke]

Re: school me merc 470 1977

so could put valve on the exchanger to dump on ramp how bout the steering cooler? seems like I could work with it!!!!!!! would gut boat and pull motor too so i can do transom, might as well do head gasket then and know what I have, what should compression be? want to check it next time I look at boat

 

[davemoore]

Re: school me merc 470 1977

For what it's worth, I have a 1983 Mercruiser 470 that I bought last year, and am quite pleased with overall... I know there are a lot of folks out there who are anti-470, but I think it's a great little motor - lots of torque, the cooling system works great, but the charging system (regulator) is pretty crappy. I'm getting ready to convert mine to an alternator. It's great on fuel, and runs quite strong. Just keep it maintained and don't run it hot.

 

[stonyloam]

Re: school me merc 470 1977

so could put valve on the exchanger to dump on ramp how bout the steering cooler? seems like I could work with it!!!!!!! would gut boat and pull motor too so i can do transom, might as well do head gasket then and know what I have, what should compression be? want to check it next time I look at boat

To tell the truth, I have never drained my PS cooler, seems to drain OK when I drain my exchanger (otherwise open the drain or pop off the hose to drain). Compression? Maybe 120-150 depending on how you measure it. Look for a low reading on #3 or 4. If you change out the head gasket make sure that you get a manual and follow the directions EXACTLY, and use a OEM Mercruiser head gasket. Good luck.