Making new sea water pick up thru hull. Sundancer 300.. Rebuilding engine.

J

jenzemann

New Member
Jun 29, 2011
13
Norway
Boat Info
300 Sundancer 2003
Engines
Twin 5.0l Mercruiser 260 w/Bravo III
Rebuilding engine - New sea water thru hull pick up..

Hi, I had a problem with my port engine, the bravo 3 sea water cooling inlet corroded and shut down the water supply.

So I had to rebuild my engine, and in the same time I put fresh water cooling on the engine, and since the sea water pick up line from the Bravo were a problem ( and the potential for a new problem in the future) I decided to plug the hole from the drive and to install a new sea water inlet thru the hull..

Has anybody done the same thing and have some preference where the best place is to put it and also what size do you use?

Is there anything else to consider? I was planning to put some holes on the top of the drive so that the water can flow in the drive and cool it, maybe a drive shower is needed??

Thank you for any comments :)

Jens from Norway :):huh:
 
Jens,

I had a cooling problem as well. We installed a throughull that sits between the BIII and the water pump. My tech was told by Merc that a sea ray is considered a heavy boat and since the drive is out of the water at plane cooling of the drive was critical. So they did not recommend cutting the drive out of the cooling circuit.

Henry


Sent from my iPad using Tapatalk HD
 
Jens,

I think a through hull is the least of your worries. I replaced my entire transom assembly last year because the water line looked the same. Actually the aluminum casting rotted out and as well as the threaded sockets. Even if we had re tapped the sockets, the mounting flange was gone.



I'll post some pictures of the throughull later.

Henry

Sent from my iPad using Tapatalk HD
 
I made that modification to my boat just this year, so only have about 20 hours on it. So far so good with no more leaking. I cut and plugged the water line at the drive, but left the top of the drive open so water can circulate thru it. On the inside of the boat I clamped off the hose between the drive and the pump. I also have been running a drive shower the last couple of years and that also was a noticeable improvement, just by the color of the oil at the end of the season. My boat already had thru hulls.
 
This is how it looked when i took it apart :)


3.jpg
 
Thanks for the info, I think i order the shower anyway.. :) Do you have any pics of the hulls? Where you locate them?

Jens
 
Yes it can and has been done. A friend did a through hull on his Wellcraft Nova because the Alpha drive could not provide enough cooling for his slightly hopped up engine.

As to where, find a person with a similar inboard. The straighter the run to the RWC pump, the better.
 
You can not put closed cooling on that engine with out changing out the computer it will not run good it is a different program for closed cooling. Your option would be to get computer re done by racers in califorina they use them on baja dune bugys.
 
vandal said:
You can not put closed cooling on that engine with out changing out the computer it will not run good it is a different program for closed cooling. Your option would be to get computer re done by racers in califorina they use them on baja dune bugys.
Click to expand...

That sounds strange! I have checked with the supplier of the fresh water kit and they had newer heard of it.? Do you have any reference or more information?
 
Go to the Merc parts lists for your engine like Bam Marine and you will se two different ECM one for raw and one for closed cooling they are different. do you have MEFI 3 or 4 #3 are no longer avaliable my friend got a 4 and had it reflased to a 3 around $900.00 new MEFI replacment from Merc $2400.00 from Busters Marine in NYC.
 
vandal said:
Go to the Merc parts lists for your engine like Bam Marine and you will se two different ECM one for raw and one for closed cooling they are different. do you have MEFI 3 or 4 #3 are no longer avaliable my friend got a 4 and had it reflased to a 3 around $900.00 new MEFI replacment from Merc $2400.00 from Busters Marine in NYC.
Click to expand...

Sorry, but you miss the point. He is only changing the raw water source.

Henry


Sent from my iPad using Tapatalk HD
 
vandal said:
Go to the Merc parts lists for your engine like Bam Marine and you will se two different ECM one for raw and one for closed cooling they are different. do you have MEFI 3 or 4 #3 are no longer avaliable my friend got a 4 and had it reflased to a 3 around $900.00 new MEFI replacment from Merc $2400.00 from Busters Marine in NYC.
Click to expand...

Hi Vandal.
I checked with the supplier again, and they have delivered this system since 2004 without having any problems with ECM and engine alarms, neither that the engine didn't run as it should.
So hopefully in a weeks time I will know if they are right or you are right :)

But thanks anyway for the warning! :)

Jens
 
You must log in or register to reply here.

Forum statistics

Threads
113,172
Messages
1,427,857
Members
61,086
Latest member
MrWebster
Back
Top