Opinion on Mercruiser 470

[Mach2]

OK, I know this is not a performance engine, but we all have to have our other toys too, right? ;)

I have a line on a mid 80s deck boat powered with a Mercruiser 470 engine and an Alpha drive. The boat itself looks to be in good shape for its age. The trim on the drive works, although half of the skeg is missing and the aluminum prop is damaged (prop shaft is still straight).

What is the opinion of this engine. I respect the opinion of the experts we have on this board. In doing some research here is what I found out:

The 470 was rated at 170 hp w/ 2 bbl carb or 190 w/ a 4 bbl
Is uses an aluminum block with a cast iron Ford 460 head and a closed cooling system
Known issues: cam driven water pump has seal issues, alternator needs conversion to belt drive
Engine runs best below 4200 rpm and has good power to weight ratio

Opinions on other boards are split-90% bash the motor, 10% love it. There must be something different about this motor since boat manufacturers were installing them as twins in boats up to 27'.

For the price they are asking for the boat I can rebuild the 470 and still come out ahead.

Any first hand feedback on the 470 would be appreciated.

[Riverman]

If I remember correctly, the alternator is fine as it is, as long as it works. A friend of mine has em in a 10' wide 28' cruiser. They run well, boat scoots along nice.

[bahamatrama]

We have 2 of them in our 30 foot searay. great till there is a problem. parts are hard to find and most people do not know very much about them. late models are much better but still no 350 chevy. part are also $$$ and when the cam surface is gone new block or machine in cam bearings

[delawarerick]

Is that the model with the stator as opposed to an alternator. If so that can be a pain in the a$$ you can add a alternator kit. I have a 140 86 model with 4400 hrs its the old iron duke and I think thats the best of the 4 cyclinder models. Rick.02

[viper15]

There good little motors. The stator models are a pain in the a--. The problem with them is they make high hp for a 4 cyl and the boat manufacturers put them in to large of a boat. When they lugged down the are prone to being short lived. They also DO NOT like to be overheated because of the aluminim block and cast iron head which expand and contract differently and blow head gaskets and warp the block. Over all well treated can live a long life. My friend has one in a 1977 19ft fiberform and other than the stator problems which were cured with and alt kit. It has never been apart.

[hsbob]

i was talking to my marine dealer last month about this very motor. bahamatrama is right get that latest model. the early models had vibration and over heating problems. find a dealer that has worked on them and ge his recommendation on how to fix the early model.

[Mach2]

Thanks for the quick responses guys. I will probably be picking the boat up this week-end. Will need to sell something in the spring as that will make 3 boats in the back yard. :cool:

[RBT]

Fooled with a lot of them over the years, they are not as bad as people claim. The earily stator motors did have some issues, They also at the same time had smaller heat exchangers. Once both are updated and you don't rev them they are a great little motor.
Don't be scared of one that has an alternator.

RT

[optimax135]

avoid it like the plaque!!!!!!

[inspectorlance]

I had great luck with mine. 1978 , The alternator conversion is not cheap if you have to do it, also your dog house might not fit right after the conversion. I hear that the water cooled voltage regulator is rare, and expensive if it goes out. I have been told that the 470 Merc was a resolution for for high gas prices of the 70's and a scare that V-8 motors were being phased out in that era. The mfg needed something good on gas that had good power. The 470 fit the bill. Another good thing about the motor is the light wieght compared to a V-8, Keeps the boat well ballanced.

Lance