Cooling fresh water ?

[Goldenusa]

I just recently purchased a 1982 marlin 16 foot boat, has the mercruiser 470 with a 170 H.P inboard motor. This engine has a what I would call a closed water sytem.. water and antifreeze . It takes raw lake water to cool the closed water in a 3" long tube with plugs in ends... My question, can I just disconnect this closed sytem and run raw lake water thru engine, in other words, get rid of this current sytem?? I will only be using this boat in lakes here in Oregon... no salt water. I also plan on changing the charging sytem to a belt drive with belt and pulley. I'm new to boating.. so take it easy on me .. Thanks for any help. Al

 

[HT32BSX115]

Re: Cooling fresh water ?

Howdy,


Well, aside from all the 470 problems that I'm sure you'll find out about in short order, is there something specifically wrong with THAT closed system?

(by the way I think 3" was too small for that engine and they went to a 4" heat exchanger later....it may be just fine in your COLD Oregon waters though!!)


Regards,


Rick

 

[DJ]

Re: Cooling fresh water ?

They put that "closed" system on there for a good reason. You have an aluminum block and a cast iron head. Even "fresh" water can cause corossion issues in a hurry.

The closed system also allows for more even heat, throughout the engine. Critical in a mixed alloy engine.

 

[Goldenusa]

Re: Cooling fresh water ?

Thanks.. thats makes since.. I do have an alum. block. Al

 

[Goldenusa]

Re: Cooling fresh water ?

Howdy,


Well, aside from all the 470 problems that I'm sure you'll find out about in short order, is there something specifically wrong with THAT closed system?

(by the way I think 3" was too small for that engine and they went to a 4" heat exchanger later....it may be just fine in your COLD Oregon waters though!!)


Regards,


Rick

Rick,
Is it the engine or outdrive?? or both, that I will fine out in short order ?? if its an engine, is there a different one I can be on the look out for ??... at this point I'm not in the this boat that much money... Al

 

[HT32BSX115]

470 problems

470 problems

Oh boy,

I didn't want to turn this into a 470 bashing contest. The 470 has several problems not the least of which included the alternator problem you mentioned. Your drive is not a problem. Do a search for 470 or 3.7L problems. You'll find out a lot that way.

If you're handy with a wrench you can fix most of the problems. There were some serious design problems with the 470 (which is why they discontinued them) that surface when they get some time on them. Hopefully yours won't have those problems.....

I don't think you want to try to run it raw water....most of the problems were not closed cooling related anyway.... There's several people here on this site with 3.7L engines that can tell you the specifics. They'll be along shortly....

I wouldn't put a lot of money in one though.... The inline 6 and 4.3L V-6 is an excellent replacement...

 

[abj87]

Re: 470 problems

Re: 470 problems

Upgrade to the 4in heat exhanger you can find them on ebay. They make kits to replace the charging system with a conventional alternator which is a nice upgrade when the water cooled reg quits. If you keep up with the maintaince its a great motor, Light powefull and fuel efficent. a good resorce for 470 info is www.breezeworks.net they have a fourm devoted to the 470

 

[Goldenusa]

Re: 470 problems

Re: 470 problems

Okay on the water sytem.. I will keep what I have... maybe a 4" heat exchanger and the charging sytem. Glad to hear the outdrive is not a problem also... I use to be very good with wrenches until my discharge from service.. I loss my left hand, but have great son's that want to help me along with friends... so shouldn't be a problem... Thanks for your info and big help to me... Al

 

[Goldenusa]

Re: 470 problems

Re: 470 problems

Thanks for the advice on heat exchanger.. I will look on ebay and charging sytem also. Right after this note to you I plan to go to that web site... thanks a great deal, Al