Old Mercruiser 470, any love out there?

[Bendie]

I have bought an old boat, because it has a (now) functioning engine and out drive. Did not run when I got it, a bit of tinkering at it fired up. Compression test was OK, 140, 110, 120, 130, engine warm. Outdrive, pre Alpha, shifts and sounds quiet. The boat's interior is trashed.
I have very little invested.
The thought:
I have seen some decent 18' 470 powered boats, with engine problems, go for very little, $500 to $700, tempting.
Am I crazy to think about running this thing? There must be a lot of these engines operating. That's the positive.
All I have seen posted up here would indicate I should try to sell some parts off and run away from this turkey.
Any opinions?

 

[Eric 3.7LX Alpha 1]

Re: Old Mercruiser 470, any love out there?

Looks like from the pics the charging issue has already been taken care of.

If the impeller history is unknown, I'd plan on replacing it this off season.

Never let it overheat, make sure your temp gauge is working and is accurate,
and just do regular maintenance and should not be any problems.

 

[gettin'even]

Re: Old Mercruiser 470, any love out there?

Is the heat exchanger a 3". If it is, I would look into upgrading to a 4".

 

[Bifflefan]

Re: Old Mercruiser 470, any love out there?

Compression test was OK, 140, 110, 120, 130

Thats not terrible. It may equal out some after running for awhile.

I like these motors. Mine is in a 21' and runs fine. Average about 5 gals of gas on the lake per day of use. Its no speed demon, but im not either. Thats what the racecars are for.

They are a bit of trouble to find parts for, but if you look they are there. I found 6 4" heat exchangers for 200.00 each, and a new fuel pump for about half the going price at a local auto parts store. And yes its a marine pump as there is no car equivelant.

I say keep it and enjoy.

 

[Bendie]

Re: Old Mercruiser 470, any love out there?

If I run this, new impellers would be a must, thanks.

Yes, it is the 3" heat exchanger. Leaks at the front, it will have to be replace.

Good input, thanks.

 

[natemoore]

Re: Old Mercruiser 470, any love out there?

You need to read up on the water pump and know what to look for regarding seal failure. Don't want antifreeze getting into your block. Like Eric said, overheat means blown head gasket due to aluminum block and cast iron head. Do you have the 4" diameter heat exchanger? Lots of info on this forum.

I rebuilt mine completely last year and am pleased with the it.

 

[EddiePetty]

Re: Old Mercruiser 470, any love out there?

Looks like from the pics the charging issue has already been taken care of......

.

...though the heat exchanger appears to be of the smaller 3" variety. If so, an upgrade to the 4" exchanger will enhance the cooling potential.

The starter wiring looks kinda hookie with that Ford type solenoid hangin' in the wind...makes me wonder where your 3.7 is getting ignition voltage while cranking.

That compression on #2 is a bit off but could just be an ill-seating valve or the pre-runner to a blowing head gasket.

My vote...for a minimum investment...GO FOR IT !!! I would.

 

[stonyloam]

Re: Old Mercruiser 470, any love out there?

No crazier than the rest of us. I assume you don't want to put a lot of money into this, so the main thing you want to watch is the engine temperature. With that ol 3" exchanger you will have marginal cooling. Gettin is right a 4" exchanger would be best, however if you decide to stick with the 3" it is imperative that you change the impeller to maximize raw water flow. It would also be a good idea to remove the end caps and clean and inspect the exchanger. Make absolutely sure that the temperature gauge is working, and keep an eye on it. Other than that keep an eye out for coolant leaking from the waterpump weep hole. Toss er in the water and have fun. You might find that it is not so crazy to like that old engine.

 

[gettin'even]

Re: Old Mercruiser 470, any love out there?

Lots of good info posted here. Also, alot of the engine internals are run-of-the-mill big block ford parts (pistons, rings, bearings,connecting rods, lifters and the cylinder head). Hopefully you won't have to rebuild it, but if you do, the parts I listed are readily available and are reasonably priced.

 

[stonyloam]

Re: Old Mercruiser 470, any love out there?

The starter wiring looks kinda hookie with that Ford type solenoid hangin' in the wind...makes me wonder where your 3.7 is getting ignition voltage while cranking.

That wiring does appear to be a little suspect. I don't see any slave solenoid either.

 

[Bendie]

Re: Old Mercruiser 470, any love out there?

Great input. Seems like I have only been seeing the negative comments on these engines.

 

[Bendie]

Re: Old Mercruiser 470, any love out there?

Terry, the start circuit is a total mess. Looking for a boat with a decent interior, and broke drive train, to put this in.

 

[gettin'even]

Re: Old Mercruiser 470, any love out there?

Great input. Seems like I have only been seeing the negative comments on these engines.

Don't worry...they will come...lol

 

[boltonranger]

Re: Old Mercruiser 470, any love out there?

Great input. Seems like I have only been seeing the negative comments on these engines.

Yes they are a much maligned powerplant.
I did not have the advantage of this forum when I bought mine;
but am a shadetree mechanic and I liked the looks of the "big-four" when I lifted the engine cover. It hasn't given me much trouble; I rebuilt the carb one summer and I did just replace the cam seals which had a fair learning curve; but all in all I'm glad I learned how to do it. Made me very unafraid of my engine.

It has a nice amount of torque; I can reach everything* (compared to bending over the hood of a car); I like the points ignition and the carburetion. It's old school but so am I.

So I guess you could say there is some "love" out there.
-br

*I should note that my engine sits in the stern with nothing in the way of the front of it; but you did say it was going in a different boat so I imagine no worries since you can do whatever when it's out of the boat OR put it in a boat with good access.

btw- this forums is fantastic for info and help with your boat - the guys always help out.