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EFI vs. Throttle Body Fuel Injected

AjskierAjskier Posts: 95 Baller
Hello All,

I hoping that you can part some of your infinite wisdom on me. I am looking at 02 Nautique that has the 5.0 motor in. In talking with the owner he told me that it was not EFI, but Throttle Body Fuel Injected. I am not sure what the difference is and was hoping that someone could explain this to me. Would there be much difference in maintenance vs if it was EFI, what are the biggest differences between those two set ups? Do you think that there would be an issue using this set up on a short lake and skiing 36 mph? Any other information that you think I might need and I am not asking, please pass it along. I really appreciate everyones help in advance.


  • WishWish Posts: 8,142 ★★★Triple Panda Award Recipient ★★★
    bottom line.... if it does not have a MPI GT-40... just walk away and keep lookn.
    >>> 11.25..a different kettle of fish. <<<
  • AjskierAjskier Posts: 95 Baller
    I didn't think the 02's had the GT-40. I thought the EFI motors were the Excalibur ones.
  • bigtallweedbigtallweed Posts: 131 Baller
    Throttle body injection is an EfI or electronic fuel injection. It is less efficient than direct port injection which has injectors in each intake runner verses a throttle body with is more like computer controlled carburetor. A 5 liter will be down on power to a 5.7 or 5.8
  • thagerthager Posts: 5,049 Mega Baller
    02 was a mix of GT-40 and Excaliber engines. Have only seen a few SNs with the 5.0 liter in them and they seem to stay on the for sale lists forever.
    Stir vigorously then leave!
  • TallSkinnyGuyTallSkinnyGuy Posts: 550 Crazy Baller
    My '97 MC Prostar 190 is EFI (electronic fuel injection) with a Chevy 350 TBI (throttle body injected). My understanding is that TBI is the simplest form of EFI. Rather than using a carburetor it has injectors sitting above the throttle body squirting fuel into the engine as needed. That fuel squirting is controlled electronically, thus it is a form of EFI.
  • Bookm_danoBookm_dano Posts: 98 Baller
    I have a '98 Mastercraft (Sportstar) with a 5.0 liter and throttle body injection. I've been very happy with it; no issues in the 400+ hours I've had it. As @bigtallweed says, it is probably a little less efficient than a multi-port set up.
    As far as engine size goes, bigger is probably better on a short lake. I'm on a large public use lake so acceleration time is not as important. Seems to have a good hole shot but I would need to time it to speed with a big skier to really know.
  • rabrab Posts: 71 Baller
    In response to your question about maintenance. The throttle body injection should be as maintenance free as port injection if not even more maintenance free. There are hardly any parts involved with a TBI compared to other fuel systems. However, if you had two identical engines one with TBI and the other with port injection the port injection would use gas more efficiently. Both in power and fuel efficiency.
  • Jody_SealJody_Seal Posts: 3,051 Mega Baller
    edited May 2015
    The Throttle body 5.0 is actually a potent package until top end. The throttle body is a EFI engine but more like a electronic carburetor. If the price is right keep the motor in the boat for a season and then re-power with a Excalibur 343 very easy swap. Not to be afraid of the little 305 if you are pulling 34 MPH or less. I would be more afraid of the GT-40 package as a lot of the replacement components are becoming NLA! Again if the price is right and it fits in your needs for a boat by all means don't be afraid of the package. and yes the GT-40 was available in 2002 however it was the last year.
    Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.

  • alex38alex38 Posts: 511 Baller
    I have one of those 02 with 5.0 it's great, I love it. It is a smaller engine yes. I ski it a lot, and have pulled thru 38 at 36 easily. It tops out at 40 mph with 1 passenger. Great price, super affordable (for me) boat.
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