motor swap from 3.0 140 merc to a 3.7 470 motor

[mikeypereira]

i am removing a 3.0 and installing a 3.7. that motor mount bolts on the bell housing of the 3.0 are 10 inches apart and the on the 3.7 they are 15 inches apart. i suppose i have to install a different inner transom piece. will i have to reseal the outter transom piece. can someone tell me how its done.

 

[Bondo]

Re: motor swap from 3.0 140 merc to a 3.7 470 motor

Ayuh,... Welcome Aboard....
Your 3.0l is set up for an Alpha transom assembley,...
The 470 is set up for a Model 1...
Getting the later model flywheel cover for the 470 is the Easiest way out...
The 470 was used with the Alpha, so the part is out there...

Why are you going from the 3.0l, which parts are everywhere,+ reasonably Cheap,..??
To the 470, that's been Out of Production for Years,+ Parts are sometimes Impossible to buy,..??

It's a serious step Backwards....

 

[mikeypereira]

Re: motor swap from 3.0 140 merc to a 3.7 470 motor

i wanted a fresh water cooled motor cause im in saltwater all the time. what will have to be done for me to remove that inner transom piece cause i found one for a 3.7 470 and i am hoping it bolts up to my merc alpha 1 outdrive.

 

[Utahboatnut]

Re: motor swap from 3.0 140 merc to a 3.7 470 motor

I would replace the 3.0 10 times before I would go the 470. Thats just me though the 3.0 is twice the motor, easy to work on AND get parts for. Why not just make the 3.0 a closed cooling system? Don't mean to sound like a jerk but man those 470's were problematic to say the least, they have an outboard charging system on them for crying out loud.

 

[mikeypereira]

Re: motor swap from 3.0 140 merc to a 3.7 470 motor

i am too deep into it now cause i bought the motor on ebay and got it in my posession. i found an inner transom plate that will mount this motor but i am wondering if i will have to reseal the outter part if i remove the inner plate.

 

[Bondo]

Re: motor swap from 3.0 140 merc to a 3.7 470 motor

but i am wondering if i will have to reseal the outter part if i remove the inner plate.

Yes...

 

[q5ka]

Re: motor swap from 3.0 140 merc to a 3.7 470 motor

Does the 3.7 have the 4" heat exchanger? Has the electrical been converted to alternator instead of generator? Has the water pump seals ever been fixed/replaced?
As an owner of this motor, I would suggest that you do a quick search about that motor before continuing if any of those questions are answered no or unknown. The time and expense from any of those jobs can justify not putting this motor in. You can possibly sell your motor on EBay for what you got in it and pickup a reman 3.0L and no changing stuff over.
On same note, if you do go with the 3.7L, I would still suggest reading here about 470 and 3.7L, go to the adults section at top of this forum to get the manual, and check out breezeworks.net. Breezeworks is dedicated to the 470/3.7L. Both forums will be very helpful when it comes to working on it.

 

[mikeypereira]

Re: motor swap from 3.0 140 merc to a 3.7 470 motor

ok thanks guys