Mercruiser 470

Just bought a FourWinns satara 204 21' cuddy cabin with an early model mercruiser 470. Got what I think is a good deal. Seller didn't know if it ran or anything about it. I stole it from him(I hope) for $900 with a double axle trailer with disc brakes. This is my first boat and im tryin to learn as much as I can. I changed all the fluids and checked voltages before starting and it fired right up. However, the 3" heat exchanger is leaking bad out of the end cap closest to the transome. The boat ran for about 5min and started to over heat so I shut it off. Hope I didnt damage anything. I Went to take the end cap off and without useing a wrench the whole end came off including the part that is threaded for the cap to bolt to. It looks like this peice was sodered on or something. I was wondering if this can be resodered or if its junk? Even if i can temporarily fix it so I can find out if the boat needs more work then its worth.

Has closed system cooling and no belt driven alternator.

Any info will be greatly appreciated. Most of what I learned so far has been from this site.

motor#5656298
outdrive# 5696159

Re: Mercruiser 470

Seller didn't know if it ran or anything about it. I stole it from him(I hope) for $900

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Howdy,

I would say that the seller knew ALL about it.

Do a search for "3.7L Mercruiser 470" here and out on the web and you'll find out exactly why you got a "steal" at $900.


Sorry about that....



Rick

Re: Mercruiser 470

Hopefully this poor fellar can re-power with a 3.0 or some like type motor, man what a deal alright.
I would assess the engine and what its going to take to make it right before buying any parts for it, especially spendy parts.

Re: Mercruiser 470

well I had the motor running seemed to run fine. No milky oil or anything. After doing some research the biggest problem seems to be overheating. Many people say with regular maintenence and a couple upgrade kits (alternator and 4" heat exchanger)it will be fine. I hope thier right. If I get it running good might just put it for sale. I'm sure I can get my money back out of it if I dont do the upgrades, just get it runnin.

As for the previous owner. He said his uncle gave him the boat 2 years ago and he never started it and didnt know anything about it except it needed an alternator. It doesnt even have an alternator so he was probably pretty clueless.

No anwswers as to if I can solder the heat exchanger though. Would like to know just so I can see what else might need fixed before putting any money into it.

Re: Mercruiser 470

You may or may not have gotten a OK deal. Sounds like it was not properly winterized, and the fresh water was not drained from the exchanger and it froze and pushed the end cap out. No milky oil is good, but the 470's don't crack very often because they have antifreeze in the block. You have to determine the condition of the motor itself. Do a compression test to determine the cylinder health. If the compression is OK you should be pretty good shape enginewise. Forget the 3" exchanger, don't put a nickel into it, Was junk to start with, get a 4" exchanger. The alternator is part of the harmonic balancer on the front of the engine, it probably has a bad voltage regulator ($$), go with a aftermarket alternator kit eg, "breezeworks". When you get it running check the weep hole on the circulating pump for leakage. If it is leaking there should be enough room in the Fourwinns to fix it with the engine in the boat. As for a repower, don't think a 3.0 would cut it with that size boat, go with a 4.3 V6. You might just have gotten lucky, Good luck.

Re: Mercruiser 470

Bubba1235 said:

Strictly a personal point of view, but I would not put so much as a penny into a 470 engine. Sorry...

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Having lived with one for 18 years, I can't argue with that advice. Here's the deal, the compression check costs $0. If all is OK (in the 140-150 range) and all are close to the same (if any are even 10# low, especially 3 or 4 you have problems) you have make some $ decisions. If you try to fix the 3" exchanger you are doomed, $300-450 for a 4". Alternator kit $300. Plugs, wires, oil change, points, antifreeze etc. another $150. Best case you will have another $700-900 in it (if you do it all yourself). Or you can sell it as is. When they say there is no such thing as a cheap boat, they mean it.
OH and I did not even get into the outdrive: oil, impeller, bellows etc. etc.$$

Re: Mercruiser 470

Well for what I paid for it I expect to put money some money into it. Plus it's almost 30 yrs old. Im not afraid to do the work myself but I dont want to get into much internal engin problems. If thats the case then I'm not even going to start. If you had one for 18 yrs there must be something you liked about it.

Re: Mercruiser 470

If the charging system on the engine works properly should I replace it anyway? Is it unreliable or ineficient?

Re: Mercruiser 470

Playakvn said:

If you had one for 18 yrs there must be something you liked about it.

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It came with the boat in '91' and I can do almost all of my own work. It has great power, and when it runs right it is a fine engine. I have learned to live with (and like) it. The problem is the iron head on the aluminum block can cause problems when overheated. If it is overheated you can cause the head gasket to leak, either between cylinders, or water leaks, or both. That is where the compression test can give you some very important information. In the 140-150 range and very close in values you probably have a sound engine and can work from there. Bad numbers and you have trouble, need to pull the head for new gasket and a valve job at the least. BTY pulling the head is not a really bad job on that engine. Once you determine if the heart of the beast is sound you can make your other decisions from there. As for the charging system, if it is working (~14+volts out) don't worry about it. The regulator is what usually fails, and it is very expen$ive, when it goes do the alternator conversion. I kind of ran on here, but it comes down to: You might just have a very fine boat there that you can have fun with for years, or not, but you gotta find out where you stand so you can make informed decisions. Good luck,

Re: Mercruiser 470

I bought a boat 4 years ago with the "dreaded" 470. It overheated something fierce when I test drove it (before I bought it) and it wasn't charging. Needless to say, I replaced the exhaust myself, and had the cam seal spedi sleeved and new seals as well as a new voltage regulator installed by a mertified mechanic. (Not all 470's have room for the alternator in the doghouse, especially if you have power steering.) In total I probably spent $1500 in parts and repairs, but ever since then I have had a great running, great starting boat. Excellent torque and good fuel economy. I couldn't help but to have a smile on my face after this past Friday. I finally took my boat out of storage. I put the raw water plug back in the heat exchanger, installed the battery, and put it on a set of muffs and turned on the water. It started in a matter of seconds! Made me have second thoughts about getting rid of it and upgrading.

My point is, when well maintained, and certain quirks of the 470 are taken care of, it can be a great little engine. Do the compression checks as stated, but if they look good, ask yourself how much you are willing to spend on fixing up your 470. I'm really glad I spent the money on mine. BTW, I do have the 4" heat exchanger.

Re: Mercruiser 470

I agree. I have the 3" exchanger and still no heat issues. as long as shes kept up on shes fine.

Re: Mercruiser 470

I have the same boat - A 1983

I am serious when I say it averaged 100.00 a week in maintenance parts alone. The problem is that every parts health is related. You overheat it and it melts a seal, a pump or broils a cable....

Last summer the 470 went to heaven when I overheated it.
Getting a more reliable and updated engine will be cheaper.
The systems on the 470 are obsolete, and at its age the parts are like working on a piece of peanut brittle.

If you do keep the 470 I would recommend a kicker. I averaged 4 tow homes a summer.

I now have a 350 with electronic ignition and an electric fuel pump.