I am considering building a fuel injection system for my 525SC. I am a novice on EFI systems in general, but have a basic understanding of them. The motivating factor is my boat uses twice the fuel and has half the HP of my friends EFI equipped boat.
-Will the Merc distributor work?
-Where would be the best place to inject fuel? (the area between the intercooler and head is only about 1 inch.
-I would only consider a MEFI controller. Should it be a 3 or 4?
Comments or first hand knowlege appreciated.

consider this instead..

http://www.professional-products.com/EFI_3.php

mefi 4A AT crateenginedepot for $600is w/ harness. Great buy! Mefiburn software and you can tune yourself.

I have a MEFI 4A complete that I will be installing on my car. I plan to buy the MEFIBURN software thats why I am stuck on the MEFI. That Professional Products set up looks great though..

525SC's are thirsty and I doubt that making them EFI will help more than about 10%-15% in fuel economy.

They are set up rich and if you tune it with an O2 sensor and lean out the jetting, it will help some also.

[QUOTE=Old Navy;3482599]I am considering building a fuel injection system for my 525SC. I am a novice on EFI systems in general, but have a basic understanding of them. The motivating factor is my boat uses twice the fuel and has half the HP of my friends EFI equipped boat.
-Will the Merc distributor work?

With the mefi a mid 1980's to 1995 chevy truck tbi twin coil distributer works plug and play, yours won't
-Where would be the best place to inject fuel? (the area between the intercooler and head is only about 1 inch.

Wherever you can.
-I would only consider a MEFI controller. Should it be a 3 or 4?

You own a mefi 4 controller, it controls fuel a little better past 100 map/boost over the early ones, use it.


Hmmm!

"The motivating factor is my boat uses twice the fuel and has half the HP of my friends EFI equipped boat."

Maybe if you took your blower belt off you could beat your "friends" boat

am i the only one here that thinks that if you have to ask these questions that there is no way on earth you have the necessary skill set to do this job ? i mean... you have a motor that is sensitive to combustion chamber temps to the point of disaster and you are going to cobble up some home built efi ?

i am really looking forward to reading this thread as this project evolves... the entertainment factor will be priceless...

Oldnavy isn't quite as dumb as he sounds in his post although he will not gain the mileage his "friends" efi boat gets because his "friends" efi boat is lighter and is turning a procharger which has signifigantly less parasitic loss than his little, tiny , itty bitty, baby jesus, roots style blower motor (my phone will be ringing in 15 minutes).
As far as the efi conversion he could probably seek qualified help and advice from his "friend" with the efi boat that gets better mileage (when its not broken) than his.
Stevexsm, I am currently finishing a efi project using a mefi4a and ramjet 502 harness on a Pontiac 455 , it will be going to dyno soon and starts and runs pretty good so far, I will send you some pics when done as I know you were involved with some Pontiac projects in the past, Smitty

This is a tech forum. If you want to be such an azz, take it to the Bilge. It really makes me want to post here.....