pair of 7.4l tbi in boat - new to forum

[gjpslp]

New to the forum and very excited about what i have been reading. i am gathering parts to convert my carbs to tbi in the boat. The boat already has the electronic ignition system used with the '90 tbi system. i plan on using the 1227747 computers and want to incorporate the knock sensors, o2 sensors, temp sensors and even the maf if i can.
Has anyone out there done this already?
Any suggestions?
Am i crazy or off track with what i want to do?
good computer to start with?


I want to lean these big guys out as much as possible without increasing my exhaust gas temps to a valve burning level and will ultimately be looking at adding water injection to cool the burn and prevent knock. i have done that in the past on a boat with natural aspiration and it was amazing.


thanks for any help and looking forward to documenting this process as i make the conversions.

Gordy

[EagleMark]

The 7747 has been used to do marine TBI. It is not a waterproof ECM so mounting location or protection has to be considered. Long harness are made to run ECM under the helm. Waterproof boxs are used elsewhere.

Also need a Park/Drive wire hooked up to throttle to get good solid low idle in gear, usually can tie off the throttle blip switch for a smooth transition into gear.

Not much knock issue on boats, most BB chips/bin don't even come with a knock sensor. But they do have a mild/safe timing table. BB bins also have Burst Knock enabled, burst knock is an anticipated knock. Knock sensors and ESC are not that hard to implement.

Running boats lean is not a good thing for power or fuel economy as they are always under load/running uphill. All the old ones I've seen are set to Open Loop and run rich. MAP sensor does do some barometric adjustments depending on altitude of the lake.

O2 sensors were not used till much newer systems and the wet/water cooled exhaust manifolds had some work done to allow for there use. Then the ones I saw wier only one cylinder, not a blend of four like in a car. It works fine if you know the mechanical of engine are in order. Reading all 8 plugs is a must on boats like this.

To be legal and safe there are many Coast Guard rules as to parts like the fuel pressure regulator is a specail unit that if it does leak will only do so into a throttle bore. Fuel lines and external pumps are a main concern. Remember gasoline fumes go down in hull and stay there! Not so much an issue on a car. Forgetting to open the engine cover and inspecting for fumes and running the blower can cause BIG BOOMS!

AFI in Michigan used to build systems for marine so give them a call.

So if you have a 90 small cap EFI distributor what controls timing with no ECM?