290 Fuel Efficiency- Gas

[Anthony]

Hi,
I'm getting serious about making an offer on a '95 290 Open with the Marine Pwr engines. Can someone give me a good idea from real experience as to what kind of fuel burn I can expect? I don't mean at WOT, just at a moderate to moderately low cruise. I'm not into speed, I just need to stay on plane. I'm OK with 15-17 knots cruise if that's going to save significantly on fuel.

Here's what I know and don't know to help give me some estimates:
- One engine completely rebuilt, the other had major "service". Engine hours are unknown, but the reuild was less than 3 years ago and there's been minimal usage since then.
- I don't know the prop pitch.
- Assume clean bottom and clean running gear.

I know it's hard to give accurate estimates, but I need to get some basic idea.

Thanks!

[George L]

I posted the #'s, go to my post on 3-7-10

[Anthony]

Thanks a lot for this George. I guess the only question I have now is, are you on plane on some of those lower RPMs? i.e. between 2800 and 3400? Like I said, I'm NOT interested in speed, but rather the best fuel economy at plane.

With proper trim tab adjustment can I plane at 2900-3000 going somewhere in the 14-16 knot range?

Thanks again for your help. The whole fuel burn issue is what has me sitting on the fence with this purchase. I know I can do better with diesels, but I'm trying to be realistic in weighing the cost and upkeep of diesels vs. the number of times I'd actually do trips in the 50 - 70 mile range. For the most part, fishing near the coast here adds up to 15-30 miles total, round trip. It's the island trips that begin at 50 and can go upwards to 150 round trip and you don't do those every weekend.

Thanks again!

[George L]

Your welcome Anthony. You get the best bang for the buck at 3200-3400 rpms. Anything below 3000 just doesn't feel right. I always run the motors at 3800, so I don't have much experience down that low. I can tell you that no trim at all gives you the best speed/rpm and any trim adjustment is only used to balance the ride. The slower you go the more your balancing if people are moving around on the boat. The faster you go the less your balancing. If your up above 4000 rpms (24-25 kt) then people can move around without the boat leaning to much. The 15% or so upward thrust of the props has taken over at those rpms and it's not the buoyancy of the hull so much that is keeping the ride stable.

[Keepin' It Reel]

If I could put my 2 cents in???? I have a 95 32' Convertible with Marine Power MPI 454's (the boat was repowered in 1999 for my previous owner) I bought Her in November '07 and brought Her home from Kent Island Maryland, I was told that the "sweet" spot to run was @ 3400 rpm's, and I cruise at roughly 21 to 24 mph's, sometimes as high as 26mph depending on fuel level, conditions etc, and for the ride home with 5 guys, gear, and in the ocean with a solid 3 foot sea, I burnt 24 gph combined. I do want to install flow scans for a real accurate reading, but probably won't do that till next year. Hope I was able to help, I know the boats are not the same size, but any information can help....

[Anthony]

Thanks for that. That's actually very valuable info. for me since your set up is a somewhat more worse condition than mine. I'm convinced now that the fuel burn is not going to be the biggest factor in my decision.

[Keepin' It Reel]

"for me since your set up is a somewhat more worse condition than mine." Not really sure what your reply is?

[tkane545]

The average fuel burn is going to be 30+ gallons per hour ( 15 - 17 per engine) depending on conditions.

[Anthony]

tkane545:
Wow!, that's significantly more than the guy with the 32' and 454's is burning.
How does that add up?

[tkane545]

You can get information right off the Luhrs web page. They list past models and if you goto the Boating article on the boat it has the performance numbers for the Marine Power, Yanmar 170's, and Volvo engine options.

The stats for the Marine Power 454 are there, 3000 RPM 15.4 knots at 17.4 gph, 3500 rpm 20.4 knots at 23.6 gph, 4000 rpm 24.5 knots at 38 gph, 4400 rpm (wot) 28.5 knots at 47.8 gph.

I think you'll find the numbers are fairly close.