Results 1 to 2 of 2

Thread: FNM Diesel Install

  1. #1
    Join Date
    May 2006

    Default FNM Diesel Install

    Pretty dang cold today which got me wishing and thinking about getting back out on the salt. I thought I would share with you my experience of putting a FNM HPEP 300hp Diesel in my 27 Seasport Navigator (W/Flybridge) that weighs in at roughly 6400 lbs dry. With full tanks (160 gal) water, food and people and a dog she's over 8000lbs. I've had a chance to pour over the numbers from last season and I think you will find them pretty impressive. The FNM 300 is approximately 100 lbs lighter than a standard Chevy 350 block and literally hundreds of lbs lighter than the Volvo 6 banger that came out. I'm running a Bravo 2 diesel outdrive.

    On average, in flat water with 1/2 tanks (approx 80 gal.) and 4 people (and a clean hull) I saw the following numbers:

    24 MPH@ 3300 RMP 58%
    26 MPH@ 3500 RMP, 65%
    30 MPH@ 3800 RPM, 75%
    34 MPH @ 4200 RPM, 100%

    I do not have a Floscan or fuel flow gauge, but I calculated it several times. Again, this is on average. At 26 MPH with the same circumstances I burned 7-7.5 gallons/hour or 3.4 MPG. I know, seems unreal but that's how she penciled out. I ran her at 80% a few times and the burn rate jumped up to about 10-11 GPH.

    I can tell you that this boat had never seen more than 24MPH prior to the install.

    Speaking of installs, the folks at Frontier Fabrication ( in Wasilla were top shelf. Mel is very personable and put up with the many questions I had before and well after the install. He knew that the key to performance would be the prop selection and he spent an entire evening with us after his shop doors closed to dial in the correct prop. I think we pulled the boat and replaced the prop at least 4 times before the numbers were ideal.

    I put almost 90 hours on the engine last summer without a single issue. I mean nothing. Not a drip, loose bolt, funky sound.....nothing.

    PM me if you have any questions. Happy to help.

  2. #2
    Charterboat Operator Abel's Avatar
    Join Date
    Apr 2011


    Those are good numbers and pretty close to what I saw in my previous boat. My 25 weighed in at 9000 empty, about 11000 loaded. At 25kts I was usually at 10.5-11gph with my Volvo D4260. Which Volvo did you have prior? 44P? It's amazing what common rail did for the newer diesels, no smoking, easier starting and a little better on fuel. Guys with my boat that had the KAD300's couldn't cruise at what my D4260 would.

    Any pics of install?
    Life's too short for an ugly boat

    Blaze N Abel Charters
    Kodiak, AK


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts