470's without heat exchangers, in fresh water only....Possible?

[Fordiesel69]

I am stuck with twin 470's that possibly overheat and the PO redid the water system all the way to the head gaskets. Oil in engines look old but great with no water intrusion, antifreeze looks good to. HX's are the 3" ones that are undersized, can I rip them off and use raw water cooling as long as it is fresh water?

If not is there a way to revive the 3" barrles as im sure they worked decent when new or merc would have been forced to replace them.

 

[solar7647]

Re: 470's without heat exchangers, in fresh water only....Possible?

No, the engine has an open face aluminum block, with an iron head so you need to keep the closed system. What you can do is upgrade to the 4in heat ex. The 3in ones just don't have enough flow to cool it as good as it needs.

Did he also change the water pumps in the drive?

Have you run it? Why do you say possibly over heat?

 

[Don S]

Re: 470's without heat exchangers, in fresh water only....Possible?

Even if corrosion wasn't a problem (which it is) you don't have a thermostat housing that can deliver sufficient water to the exhaust elbow to prevent burrning of the rubber hoses, and still leave enough water to cool the engine at the same time.

 

[Fordiesel69]

Re: 470's without heat exchangers, in fresh water only....Possible?

Boat was purchased by mistake at a car auction, if you leave and not pay, you are banned forever........ Owner states it did overheat but it is fixed now.... yeah sure it is, then why is it for sale at an auction and not CL?

Price was too good to be true and lots of stuff needs done before sea trial. I see the small heat exchangers and see only one engine with an external alternator. So it has been worked on. I have a feeling the dreaded 470 overheat I read about each year is going to plague one or both of these engines.

I know 4" HX's are the way to go for better heat removal, but I plan to roll this boat and just want it to run good and be safe.

 

[Bt Doctur]

Re: 470's without heat exchangers, in fresh water only....Possible?

Maybe the riser.elbow is clogged up some.Were they replaced?

 

[stonyloam]

Re: 470's without heat exchangers, in fresh water only....Possible?

IMHO, what you need to do is remove the end caps and thoroughly clean out both exchangers (as recommended by Mercruiser) to maximize their efficiency. Then change the impellers (and housings if need be) in both outdrives. Make sure your riser gaskets are OK and that both thermostats are functioning correctly. If you can maximize the efficiency of the three inchers you might just be OK, and if you decide to keep the boat, add some four inchers down the road. In the meantime make sure your temp gauges are working and keep an eye on them. Good luck.

 

[dubs283]

Re: 470's without heat exchangers, in fresh water only....Possible?

Price was too good to be true and lots of stuff needs done before sea trial

usually a bad sign

get rid of the boat however you can

 

[solar7647]

Re: 470's without heat exchangers, in fresh water only....Possible?

Well if just want to get rid of it you may do better on your profit if you just exchange the engine with some good running 4.3l. It's a pretty simple swap if they are alpha drives witch depends on the year. You can pick the engine up for around 2k that seems to be the going rate that I have been seeing on eBay.

Then you can recoup a lot of the money spent on the motors by parting out the 470s. Since they don't make 90% of the parts any more people pay almost anything for the parts. You could get at least $200 a peace for the manifolds.

I say this cause anyone who knows about 470s or looks them up online will end up staying far away from your sale. At least every person who comes on hear and says " looking at buying a boat it has a 470 can you tell me what to look for" everyone tells them to RUN!

 

[stonyloam]

Re: 470's without heat exchangers, in fresh water only....Possible?

Well if just want to get rid of it you may do better on your profit if you just exchange the engine with some good running 4.3l.

Well OK.... except he needs TWO of them :facepalm: LOL. If you want to get rid of it, just get rid of it, but if you can get it running and staying cool it will be a much easier sell, with little extra cost. Good luck.

 

[dubs283]

Re: 470's without heat exchangers, in fresh water only....Possible?

At least every person who comes on hear and says " looking at buying a boat it has a 470 can you tell me what to look for" everyone tells them to RUN!

but on the other hand, i do still see posts like, "i just bought my first boat, got a sweet deal on it, it has the 470 motor with closed cooling which i thought was a good thing for a boat engine, how do i start getting this thing ready for the water??"

so, there are a lot of people out there who will buy things with knowing nothing about em!!

 

[Fordiesel69]

Re: 470's without heat exchangers, in fresh water only....Possible?

My plan is to goto the marina very late, like 11:30PM and power them up on the trailer. Ramps are cement for a very long way into the water so washout does not seeem to occur here. Not to mention people have power loaded here so many times!!! Will check temps and make sure they operate correctly before launching.

Have a little wiring stuff to figure out, and will give it a try.

 

[solar7647]

Re: 470's without heat exchangers, in fresh water only....Possible?

but on the other hand, i do still see posts like, "i just bought my first boat, got a sweet deal on it, it has the 470 motor with closed cooling which i thought was a good thing for a boat engine, how do i start getting this thing ready for the water??"

so, there are a lot of people out there who will buy things with knowing nothing about em!!

Yes very tru...lol and they still buy them after being told not too. Lol

 

[Fordiesel69]

Re: 470's without heat exchangers, in fresh water only....Possible?

Rain all f$^%#$ week. Looks like I won;t even know how they run until sat.

 

[Bamaman1]

Re: 470's without heat exchangers, in fresh water only....Possible?

I have a 470 in a 16' v hull boat that's always been a good performer--economical and fast on top end. I never had any kind of overheating problem, and winterizing was always a breeze with the heat exchangers.

The heat exchangers are very simple things. If you have any doubts about them, pull'em off the boat, drop the caps out of the ends and you can visually inspect the tubes inside for clogs, etc.

I suggest getting a water cuff at WalMart, start the engines and run them for awhile to see if they overheat. Then, go to the lake.

As an experienced boater: Any time I purchased any used boat, the first thing I would do is change the fuel filters, water pump impellers, the lower end grease and spark plugs. If it was an inboard or inboard outboard, I'd also change oil and filter in the engines (looking for any oil contamination). If the boat didn't run perfectly, I'd either rebuild the carb's or clean'em (if 2 strokes).

 

[Fordiesel69]

Re: 470's without heat exchangers, in fresh water only....Possible?

This rain is making my blood boil. Cannot even put batteries in them to see if they run. Maybe sat we will get a break.

Will definatly take the time to do the HX's as im sure they need doen anyways.

 

[jopes]

Re: 470's without heat exchangers, in fresh water only....Possible?

Yes very tru...lol and they still buy them after being told not too. Lol

But, I got a killer deal on it and the interior is in mint condition.