FWC 165 Mercruiser IL6

[FreeBeeTony]

I am in the process of buying a FWC kit for my 165 IL6 Mercruiser. I have heard of possible problems using a fully closed system, cooling the block and manifold. Seems that because the manifold is so big, there may be a problem cooling it, thus possibly not being able to cool the block? I intend on using the water pump in the outdrive, I have also heard that the water supply may not be adequate from here. Has anyone had any experience installing one of these kits on an IL6 GM250 engine?

 

[WillyBWright]

Re: FWC 165 Mercruiser IL6

Is that a new replacement motor? If not, save your money. That block is already covered with rust inside. The coolant will never run clean, and the heat exchanger will clog with flakes of rust very quickly. You'll be having constant overheating problems as a result and no amount of flushing will remove all of the rust.<br /><br />As for the water pump, your only alternative would be to put a fitting thru the hull to grab the water with an engine mounted pump. The hose from the drive to the transom unit isn't nearly large enough to get proper amounts of water. Stick with the one in the drive. Rebuild it if it's more than a few years old.

 

[Bondo]

Re: FWC 165 Mercruiser IL6

I couldn't Disagree More.....<br />

The hose from the drive to the transom unit isn't nearly large enough to get proper amounts of water.

That is the Same hose that feeds the cooling needs of All the Mercruiser Engine/outdrives Up to the newest models..... The Mod.1/Alpha1 Raw water pump impeller will move Plenty of water.....<br /><br />Tony,<br />I remember you've had your drive apart... <br />But, Didn't you just Rebuild that Motor, Last winter ??? If so, What did the cooling passages Look like when you had it apart ??? <br />I'm Guessing that you want to run the Raw water, From the outdrive, to the heat exchanger,+ Then Dump it into the exhaust Risers...... I wouldn't do it Any Other Way.... Just buy your heat exchanger Accordly..... If you're concerned about it, Go to a Bigger Heat Exchanger.....<br />Even though I boat in Freshwater, My current project is going to be plumbed this way....... I'm doing it for Cabin Heat... I like to Start Early,+ Stay Late... Fishing anyway.....<br /><br />Make Sure of the condition of your engine mounted waterpump.. drop in a 180* T-stat,+ You're Boating...<br />Even If there was a rust Flake issue, heat exchangers are pretty easy to clean,+ Filters can be added.....<br />And, The Anti-freeze may not Stop the rust-thru, It'll Deffinetly Will Slow the prosess.....

 

[FreeBeeTony]

Re: FWC 165 Mercruiser IL6

Yes bondo, you remember correctly. The engine was rebuilt last winter and the block was "boiled-out". The water pump in the drive was replaced when I rebuilt the lower unit (remember that?).<br />The circulating pump on the engine is also new.<br /><br />I was going to plumb it just as you said, have the raw water enter the heat exchanger from the transom, then from the heat exchanger to the riser (which was also new). The manifold was going to be cooled by the anti-freeze.<br /><br />I was told that because the manifold is so big, the exchanger might have a difficult time keeping up with the heat using the water supply from the outdrive.<br /><br />Ever hear of a MST Flusher ? I was told that this might be an alternative to installing a FWC system, it allows the engine to be thoroughly flushed while the boat remanins in the water.

 

[Bondo]

Re: FWC 165 Mercruiser IL6

Tony,<br />Horsepower = BTUs...<br />Buy a Heat Exchanger for a V8 if you're Worried about it.....<br />You can Always use a heat exchanger that's too Big....(T-stat will take care of that)<br />But, if it's too small, you're SOL....<br />Plumb it to run from the exchanger to the block, Then then Manifold, back to the exchanger....<br />You might need a By-pass at the T-stat, to full flow the manifold.... You'll have to decide....<br />I see all of those Flush systems as "Better than Nothing".... Salt Leaches into the Iron when it's hot.... It's something that doesn't flush Easily.....But, It's No Doubt better than leaving your engine full of saltwater All the time.....

 

[FreeBeeTony]

Re: FWC 165 Mercruiser IL6

bondo, what do you mean by a bypass at the t-stat to full flow the manifold? Do you have a digram you could share with me?<br /><br />Thanks.....<br /><br />Tony

 

[Bondo]

Re: FWC 165 Mercruiser IL6

Tony, go here,<br /> http://www.marinemechanic.com/site/page130.html <br />It's a weird site, but I'm pretty sure there are Several Different plumbing Dia.s there...