350 v8 mercrusier raw water cooling

[flashback]

just wondered if any of you folks ever added an addional belt driven raw water pump, or maybe even removed the stock pump in the outdrive in favor of a belt driven one that is easier to work on? also while were on the subject, is there any advantage to piping the exhaust thru the transom instead of thru the outdrive other than it sounds good.......

 

[Bob_VT]

Re: 350 v8 mercrusier raw water cooling

Thru the hull exhaust is a few extra HP points. As for the sound well that depends on where you go with the boat. Noise polution gets to be a key item on many lakes now.<br /><br />Not sure of your pump idea.<br /><br />Bob

 

[Trent]

Re: 350 v8 mercrusier raw water cooling

No problems doing it. You will need to remove the impeller in the lower unit if you do this.<br />This is also sort of pricie to do. Pump and brackets, seawater pickup and seacock valve.

 

[flashback]

Re: 350 v8 mercrusier raw water cooling

Thanks for the thoughts. I guess my main objective is to make my boat as simple to work on as possible. I figured if I stocked and extra impeller and belt on the boat it would be easy to repair while on the water..I guess the next thing is to figure out how much water I need if i make this change.. I kinda like the way these go fast boats look like they have a fire hose spraying out the back end, kinda gives me a good feeling to see that much water going thru the system, but on the other hand, the bigger the pump, the more HP it takes to turn it.........?????

 

[amtsst]

Re: 350 v8 mercrusier raw water cooling

Here's your solution!<br /><br /> http://www.homefirepump.com/specs.html <br /><br />5 horse Briggs and a 120gpm pump. keep that sucker nice and cool.<br /><br />

 

[BigBabyLou]

Re: 350 v8 mercrusier raw water cooling

Flashback, to answer your question about the exhaust: as Bob said, you gain HP by not forcing the exhaust gasses through the outdrive. Sometimes you need the extra HP, sometimes you want a quiet ride, but which one to choose? Should you stay with your existing setup or repipe the exhaust through the transom?<br /><br />Which way to go? Tough question. But now you can go both ways. I've seen a system called "Captain's Call" and it's actually an addition to your exhaust which can send gasses either through the transom or the quieter way. You just flip a switch and a flap in your exhaust system can route the gasses the way you choose. <br /><br />I've been thinking about this for a very long time but am waiting for the prices to drop a bit more. It's a pretty new thing on the market but I'm not ready to pay a grand for it.<br /><br />Anyone on this forum with this setup?<br /><br />Lou

 

[denniz]

Re: 350 v8 mercrusier raw water cooling

Ive installed alot of captains call systems, theyve been around for a few years.Made by Corsa performance. 1/2 the price of Mercruisers version. Pretty simple installation after youve done a few. Dont look for a speed/horsepower gain though, unless you have a restriction in the factory system. Ive learned alot of tips on installation, if your going to do one let me know.

 

[flashback]

Re: 350 v8 mercrusier raw water cooling

well I made up my mind regarding the exahaust, it would mean 2 exta holes in the hull and thats an addional risk I don,t want.. as far as the external pump goes, it would be one extra hole, unless I can use the outdrive as the intake, which may be OK. The whole point is to be able to repair the system on the water....and make it simple.......thanks for the info

 

[denniz]

Re: 350 v8 mercrusier raw water cooling

Why dont you want to pull the boat out of the water and replace the impeller? If you have a impellar go bad the blades usually break and end up restricting water flow at some point. If you bolt a belt driven seawater pump on, how do you know the hoses to it are clear? If you use a thru hull water inlet, How are you going to install it in the water?

 

[flashback]

Re: 350 v8 mercrusier raw water cooling

Rod-knocking, I don,t have a problem pulling the boat out of the water, shoot, its on a trailer most of the time unfortunatly, no, what Im talking about is if the pump quits 10 miles from where my trailer is, I can fix it on the water and get back to my trailer. I do like that captains call deal tho, It seems much like an exhaust system I used to have on a 1963 ford galaxy with a 406ci ........sounded great on the freeway but got a lot of tickets..

 

[denniz]

Re: 350 v8 mercrusier raw water cooling

I see what your trying to do, Might be a good fix. Ive got a 390 amx that sounds about the same.

 

[scottmech]

Re: 350 v8 mercrusier raw water cooling

About putting a sea water pump on the engine to make it easier to work on....<br /><br />Have it set up that way on mine...a real pain in the behind to get at. If you change the one in the drive at the beginning of each season you should have nothing to worry about. My brother had the same one in his for about 5 years before it went. And thats was with him starting it OUT of the water every time we launched.

 

[denniz]

Re: 350 v8 mercrusier raw water cooling

agree with scott, maintence=no problems