Vintage 1986 170 4 cylinder mercruiser and drives - Help !

[4winnsskipper]

Im looking at a boat that has twin 1986 "170" 4 cylinder mercruiser engines and drives. the boat is pristine but has 1400 hours on it. questions are

a) anything i should be aware of that these engines may be notorious for?
b) what is the drive called? is it an alpha? or something else? are these drives "good" or solid?
c) the twin outdrives do not counter rotate - how big of a deal is that? it seems older boats generally don't have counter rotating props.
d) anything special to look for? i will for sure have a complete survey done, just wanted to check things out on my own before even getting that far on the purchase.


I know some have told me that this is not enough power for a 27' sea ray but according to sea ray archives the boat is only 6,050 lbs and i'm using it primarily for trolling a mile or two offshore.

Thanks

 

[Don S]

Re: Vintage 1986 170 4 cylinder mercruiser and drives - Help !

a) anything i should be aware of that these engines may be notorious for?

1. Aluminum block, open deck design. Guaranteed to blow the head gasket whenever you have an over heat.
2. Major parts of the engine are NLA from Mercruiser (Intake manifold, exhaust pipe from eng to drive.
3. Outboard type charging system with $400 stator, NLA rotor, $400 regulator. Most people end up buying a conversion kit to convert to alternator type charging system like all other IO engines.
4. Cam seals are noted for failure, most use speedy sleeves to patch the cam to keep antifreeze out of the crankcase oil.
5. This type engine is commonly knows as a 470. It's a 3.7L engine built by Mercruiser and never used in a car, but it does have a Ford 460 cast iron head.
6. 1989 was the last year the 470's were used.

b) what is the drive called? is it an alpha? or something else? are these drives "good" or solid?

Alpha I

c) the twin outdrives do not counter rotate - how big of a deal is that? it seems older boats generally don't have counter rotating props.

Just a counter rotating lower unit on the one outdrive.

d) anything special to look for? i will for sure have a complete survey done, just wanted to check things out on my own before even getting that far on the purchase.

You have to enjoy constantly working on the engines if you want to own a 470........ or two

When they run, the engines do have a lot of torque, but that is about the only good thing I can say about them

 

[Bondo]

Re: Vintage 1986 170 4 cylinder mercruiser and drives - Help !

Im looking at a boat that has twin 1986 "170" 4 cylinder mercruiser engines and drives. the boat is pristine but has 1400 hours on it. questions are

Ayuh,... The infamous Merc 470s,...
Mercruiser's red-headed b*stard step-child they've all but abandoned...
for Free, that boat ain't worth it....

 

[4winnsskipper]

Re: Vintage 1986 170 4 cylinder mercruiser and drives - Help !

other boat im looking at is another 1986 and a 1991 sea ray with twin 4.3 LX engines with alpha drives, what about those engines?