Merc 470 overheated and shut down on the water

[JJJZJ]

I just got my 82 century riviera 17'er back in the water after getting the ring gear on the flywheel replaced and got about 1/2 hour into my cruise when i looked at the temp gauge and noticed the engine was in the red. the oil gauge also showed it was on the low side in the red. I immediately turned it down to idle and got to within 100' feet of the dock when the engine quit and was smoking, i swam it into shore and let it cool down. I got it running tonight so nothing seized, but i noticed the oil gauge back to normal. I also noticed the bilge full of engine coolant. Does anyone have any clue as to what happened? Im new to boating and could use some help on this one. The shop did take out the motor, is this there fault in any way?

 

[Don S]

Re: Merc 470 overheated and shut down on the water

When was the last time the impeller in the drive was replaced?
Why was the engine out of the boat?
You really didn't give enough information to give any kind of guesses as to WHAT is wrong, let alone WHO is responsible.

 

[JJJZJ]

Re: Merc 470 overheated and shut down on the water

just recently bought the boat so i am not sure when the impeller on the drive was replaced.

I had the motor out so due to the fact that the ring gear on the flywheel got chewed up by seized starter

Im rather new to boating so that is part of the reason i got this starter boat to learn. What other kind of info can i give you guys to help me out? im a tad lost right now...:|

 

[Don S]

Re: Merc 470 overheated and shut down on the water

A starter boat is a NEW, boat with no options that allows non boaters to learn boating.
Buying a 25 year old boat with a 470 is about the most expensive way you could learn boating. What you will learn is why Mercruiser quit making the 470 style engines, and just how expensive it is to repair them.
If you want a starter boat to learn and enjoy boating, then buy a new boat, and hopefully you don't end up with a bunch of warranty problems. If you want a starter boat to learn how not to buy a boat or how to repair old boats and spend lots of money, then you have the perfect boat.

 

[bigbrownbuku]

Re: Merc 470 overheated and shut down on the water

so grim don. there is an element of truth to what don says.
the waterpump in the drive is where you should start.
the oil pressure on 470's was prone to dip low at times and forced merc to issue a bulletin on "acceptable" oil pressure at one time. coolant in the bilge is a sure sign of overheat. when the drive is being serviced have the cooling system on the engine tested also. find an old guy that cut his teeth on that engine or you will be getting a whole pile of grief from your ol' lady.

 

[rodbolt]

Re: Merc 470 overheated and shut down on the water

the 470 motors used a closed cooling very similar to your car, with coolant in the bilge either the overflow tank as to full and vented into the bilge,the overflow tank is missing or you have a coolant leak. the standard stant radiator presure tester can presurize the cooling sytem and check for leaks.
measure the diameter of your heat exchanger, make sure its the 4" one or overheating will be a common isue, that motor does not tolerate overheats well and is very very prone to headgasket failure.
its an open deck design block which is very poor for marine or industrial use.
buy the factory shop manual.
DO NOT let joe tool box look at it. IT IS NOT a car motor and most automotive techs do more harm than good when looking at the 470 series of MCM motors.
for a starter boat you picked almost the absolute worst you could pick.
but get the factory mercruiser manual and read read read then read it again, cover to cover. then open the engine box.
trust me that 470 has more curves than marilynn monroe.

 

[JJJZJ]

Re: Merc 470 overheated and shut down on the water

Well I will heed your guys advice on the cooling system and check it out. Perhaps i didnt pick the best boat, but I wanted to learn somehow. I may play around with it this winter or sell it off, we will see. I put a minimal amount of money into it, so i wont feel too bad letting it go.

 

[Don S]

Re: Merc 470 overheated and shut down on the water

Before you run off and buy something else, have a look at this thread.

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=24;gtid=1178542

 

[dry dock]

Re: Merc 470 overheated and shut down on the water

check the seals in the circulation pump on the engine. I have the same engine and replaced the seals this summer. it wasn't that hard but you will need the engine manual. good luck

 

[8AteEight]

Re: Merc 470 overheated and shut down on the water

Whoa, hold on everybody... Ive had experience with a 470 and a 170/470. They arent the greatest motors, and they are expensive. But Ive had lots of good experience with 'em too.

I know Im gonna be flamed for this opinion, but they are super easy to winterize, and AWESOME for the beginner boat.
First, the smart beginner doesnt go blow 10 large on a NEW hobby,
Also, the beginner doesnt usually know to winterize their boat, (the salesman wont bother to tell them anything that actually helps)

I got my (first) boat with the 170/470 for chump change. It had water in the oil (sat in there for at least 6 months) and wasnt winterized that winter, and it had water in it again after I changed the oil and warmed it up. I changed it the 2nd time, and havent had a single motor or water problem in 3 years now.

If this were an open water cooled system, Id be buying a new motor. I didnt even have to replace a thing, other than the oil filter.