Crusader 350XL fuel burn question

[EX-YANK]

I am still getting acquanted with my new boat , and trying to measure my fuel burn.

Now I wondering if I have a problem with my hour meters or if these engines aren't that bad at guzzling fuel if you keep it to 3000 RPMs maximum.

When I last filled I wrote down the hour meter readings. Since my last fill I have put on about 18.5 hours. I am running it in a river at a tops of 3000 RPMs which pushed it between 14-16 knots dependeding if I am traveling with or against the tide. There are no swells or chops to work against.

The boat holds 184 gallons. It will probably have 19 hours when I do the next fill up. Let's say it is bone dry after nineteen hours , then that equates to 9.68 gallons/HR. 184g/19hrs.

Does this seem right or could I have a problem with my hour meters. I have not kept track of the amount of time I have been running the boat each time I have taken it out with a seperate watch since the last fill up to validate the accuracy of the boat hour meters.

These engines are 1996 Model Crusader 350XL with four barrel carburetors.

[katman2860]

That sounds not to far off on that engine at those rpms because you are not really using the 4 barrels if you are talking of a single engine application
If you are talking twins it would be twice that as they seem to only get .75mpg on most boats at 3000rpms

[EX-YANK]

I am talking twin 350XL burning combined at just under 10ga/hgr at 3000 RPM maximum. Doing the math is 1.75 MPG. Does that seem right?

[BUDC]

Nope, it does't sound possible to me.

I have a 24 Albe with a single 350 - 4 barrel. It cruises -on the primary 2 barrels - at 22-24 kts at 3200 rpms, burns 14.5 gph and gets 1.666 N-mpg. For you to use 10gph (4.5gph less) for 2 engines doesn't sound feasible to me.
If you are doing that well, I need a new engine for sure!!
Keep us updated.
Thanks,
budc

[EX-YANK]

I agree it doesn't make sense. I'll have to test my hour gauge against someother time keeping device.

[EX-YANK]

Well I filled up yesterday, and I think I might have inaccurate hour meters. The boat took 155 gallons, and the hours meters had advanced 20 hours since my last fill up. That's 7.75 GPH. Even if I throw out five hours for time spent at trolling speed ( 1000 RPM) and fifteen minutes of warm up idle time before each trip that is still under 11 GPH. I would believe that for a single but not twins. However this is not a very heavy boat either. It is a Phoenix 29SFX that supposedly wieghs 9500 lbs dry.

I'm going to measure my hours gauges this weekend aginst elapsed time of my GPS to see if they match.

[EX-YANK]

I ran the boat for one hour per the time display on my GPS,and exactly one hour elapsed of my Engine hour meters during this time.

It appears these enegines don't start guzzling fuel until you push them past 3000 RPMs. Of course I'm only doing about 13-15 kts at this RPM.

[BUDC]

Unless someone can tell you, take a knowledgeable friend to watch your carbs while you're running for the opening of the other 2 barrels. If you can get a good cruise just below that RPM you've got a good setup. A flow meter will do it better and more often, but friends are pretty reliable and economical for a one shot effort.
My single does 22-24 kts at 3200 rpm -- about 300 rpm below the secondaries. It is a Quadra-Jet, so when the secondaries open, Katy-bar-the-door on fuel consumption and not that much more speed!!
Sounds like you may have a pretty good setup but I wonder if you could use more prop. What is your Wide Open Throttle rpm's??
budc

[Grady23]

Because there are so many variables that affect fuel consumption, I would SERIOUSLY consider installing a Flo-Scan system. That takes all the guesswork out of the equation. I have the Yamamha fuel management system and I depend on it more then ANYTHING else on the boat for fuel situations.

[EX-YANK]

The flo scan is definetly on my list of add on, and my previous boat had the yamaha fuel management , and was what I relied upon also.

WOT is/was 4400 RPM, sa recommended by crusader. Now I do have a bent prop on the port engine. ( hit some unknown object on the river recently) One of the reasons among other why I keep it under 3000 RPM. It will be fixed soon.