Carborator Conversion

firstpft

Cadet
Joined
Jul 6, 2017
Messages
11
I have twin 270hp Crusaders. 2007 with 4 barrel carbs. I'm am curious about converting it to a throttle body fuel injection system, mainly for fuel efficiency reasons. What are the pros and cons? A mechanic told me it would cost about $10,000 but I've seen kits for between $800 and $2,000. Sounds like a lot for labor. Is there a difference between kits for marine applications or would an automotive kit work?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
Messages
47,307
there is no fuel efficiency on EFI over a properly tuned carb.

Automotive kits do not work and are not SAE J1171 compliant. you need to have a proper marine fuel and ignition system (to keep you from blowing your boat up)

none of the sub-4000 kits work reliably on cars either. they work ok, however systems such as the bolt-on FI-Tech, FAST, and the holley end up in the trash after a year or so as they fail.

your mechanic was talking MPI or Multi-Port fuel injection and not TBI which is a glorified carburetor. MPI requires a new intake, fuel module, plumbing, injectors, ECU, harness, etc. and yes, to buy all that stuff for two motors is about $8k. the rest would be labor.

If you want fuel efficiency in a boat, buy one with oars, paddles or a sail.
 

alldodge

Moderator
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Mar 8, 2009
Messages
40,582
You might gain a tad on efficiency but pretty sure your not going to notice. If you have inboards really doubt you would see anything extra. The marine stuff cost more, and do not recommend using the auto stuff.

Maybe sell your motors and buy reman motors, but still going to be expensive
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
Using the Auto stuff in a boat is not even legal

Mercury does offer complete engines, with the ECM, complete EFI, ready to drop in. The cost isn't as bad as you would think.
 
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