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454 carb to mpi

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bitsamonkey

New member
"Hi guys, this is my first pos

"Hi guys, this is my first post.
I've got a 1999 454xl 350hp in a 25' Whitewater center console. 1.52 velvet drive 16x18 4 blade with a medium cup. Rochester carb. Engine runs great, but I would love to improve my fuel consumption at cruise. Presently I cruise at about 28 mph at 3000 rpm and burn about 14 - 15 gph. I would definitely convert to mpi if it will improve on that. Any feedback from someone that's gone from carb to mpi? I was at the Miami boat show the other day and talked to a Crusader rep who claimed 20% improvement mpi to carb!"
 
"Welcome to the board!

If t

"Welcome to the board!

If that rep claimed a 20% improvement BEFORE you gave him the boat details - be wary.

You'll find it cost ineffective to go to MPI with new stuff. If you can find a complete "running takeout", maybe, but don't expect it to be a huge improvement.

I'd start by making sure the engine is tuned and is happy with the current prop. If that's all in line, you can probably make carb adjustments and get close to that 20% savings for a lot less $$$. The reality is that a given hull takes so much torque to spin its prop and that requires fuel to be burnt. You want to make sure that the fuel amount is adequate, not excess. Hoping for anything beyond that is wasted effort."
 
""you can probably make ca

""you can probably make carb adjustments and get close to that 20% savings for a lot less $$$. "

I'd agree. But first, how much throttle do you currently have left at cruise? OR, what is current WOT rpm? You're showing a pretty good cruise speed for a single engine in a deepV hull."
 
"Right! Funny thing about car

"Right! Funny thing about carbs: In a marine application they tend to run at one throttle setting most of the time and, properly set up, can get about the same economy as EFI. It's in the up and down throttle application of automotive use where EFI shines.

Jeff"
 
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