HP500 EXCESSIVE FUEL USE IN 28' DECKBOAT

[Outofgas]

HEY GUYS, NEW HERE AND I'M LOOKING FOR SOME FEEDBACK. I HAVE A NEW 28' MAGIG DECKBOAT, 12HRS,
WITH THE HP500, XR DRIVE, ALL THE GOODIES.
WE ARE BURNING THROUGH THE PETROL!!!!?
WE BURN A FULL TANK, ONE SIDE, FROM BRIDGE TO DAM AND BACK:JUST CRUISING @ 4000 RPM.WE ARE NOT OVERLOADED; FOUR ADULTS, A PAIR OF KIDS.
LOOKING FOR HELP? WHEN I RE-FILL THE TANK, I CAN ONLY GET 20 GALLONS MAX INTO THE EMPTY TANK.
FRUSTRATED! :confused:

[Keith E. Sayre]

Something isn't right. Take it back and have
Mark or Clue check the overflow hose to the tank
to make sure that it's working right. You could
have a pressure problem if it isn't bleeding the
air properly as the gas is filling it up? That
same problem could create suction when draining
the tank and could stop the flow of gas to the
motor which could make you think it was empty?
That's one possibility? Good luck. FYI--the HP500 won't use too much more gas in a day than
the 496 packages would. Good luck.
Keith Sayre
Conquest Boats
Lake Havasu City
928-680-1400

[mike37]

HP500 gas hog
496 ho not a gas hog

[Jrocket]

I've got an HP500 in my Mach26 and it does ok on gas,especially for the way I drive. :D You also have alot of boat there(28foot).How much trim are you running at those rpm's? Is the boat packing air under it or plowing the water?

[riverliver]

Outofgas:
WHEN I RE-FILL THE TANK, I CAN ONLY GET 20 GALLONS MAX INTO THE EMPTY TANK.
FRUSTRATED! :confused: May be the tank is not empty and it is reading empty.
Iam runnins a blown 502 with 2 850s 0n top of a 871 and can run from havasu springs to topoc and back on a 1/2 tank or so if iam not running to hard.

[Trash]

As a reference mark, you should be getting about 2-2.5 mpg at that rpm with that motor. Like Keith said, check the tanks, then get a GPS and run a certain distance with a topped off tank, fill it up again, note distance and calculate mileage. I usually get around 3 mpg with a 350 Mag/EFI MP in a 21' that weighs around 3800-4000 lbs loaded. BTW that's at 3000 rpm.

[Sandbar Mike]

My 29 cat w/540ci will run from the London Bridge to Havasu Spring and back on half of one of the tanks, I guess that means about 22.5 Gallons.
Thats at 4600rpm @ low 70's mph
I'll bet you have a bad sending unit in one of the tanks,
2cents

[OC-PARTYCAT]

I have the same problem with my partycat. The guage is reading empty but only about 20 gallons will go in. The problem is, the tank is only half empty (or full) :p . The sender in the tank isnt long enough.

[Keith E. Sayre]

OC-Partycat just made a valid point. Most deckboats have very long and thin gas tanks
which makes it difficult for the senders to
measure the gas accurately. A half inch
vertically is alot of gas yet doesn't change
much at the senders position.
Keith Sayre
Conquest Boats
Lake Havasu City
928-680-1400

[MKE - POWER]

OUTOFGAS is a friend of mine. His problem is that he is actually running out of gas, no more go.
It has happened three time on the lake, and last
week when he was putting it on the trailer.
He has only been able to fill it with 20 gals.
I don't mean to to step on his post, but I don't know if he has been in town recently.
Anyway, we think that maybe they put smaller tanks
in by accicent, or therre is a pick-up problem.
We talked to the salesman at the L.A. show, and he wasn't sure of the tank sizes, maybe 25 a side.

[Jrocket]

MKE - POWER:
OUTOFGAS is a friend of mine. His problem is that he is actually running out of gas, no more go.
It has happened three time on the lake, and last
week when he was putting it on the trailer.
He has only been able to fill it with 20 gals.
I don't mean to to step on his post, but I don't know if he has been in town recently.
Anyway, we think that maybe they put smaller tanks
in by accicent, or therre is a pick-up problem.
We talked to the salesman at the L.A. show, and he wasn't sure of the tank sizes, maybe 25 a side. If hes running out of gas then its either the pick up tube has a hole in it half way up or the tank is not vented and its vapor locking the system... :)

[MKE - POWER]

Jrocket
Thanks, we are looking at all possibilities before
he takes it back to the Mfgr and it sits....... there. The salesman thought the tanks were each @
25 gals. Could this be possible with such a large boat? they should be at least 40 or 50 each?

[BoatFloating]

MKE - POWER:
Jrocket
Thanks, we are looking at all possibilities before
he takes it back to the Mfgr and it sits....... there. The salesman thought the tanks were each @
25 gals. Could this be possible with such a large boat? they should be at least 40 or 50 each? I would say they should be 40 gallons each. 50 gallons total on that size boat would be small, but if you are saying no more go and only putting in 20 gallons that's still 5 gallons short. I would say most gauges aren't that accurate, but 5 gallons are a little high, I would say 2 to 3 gallons is likely.

[MKE - POWER]

We are headed out to LHC on Thursday for some riding and boating. We plan to record accurately how much fuel it takes. The tank on one side is supposed to be empty, because it ran out and died
loading on the ramp last time out.

[MKE - POWER]

We are headed out to LHC on Thursday for some riding and boating. We plan to record accurately how much fuel it takes. The tank on one side is supposed to be empty, because it ran out and died
loading on the ramp last time out.

[DogHouse]

I have the cat version (same tanks as far as I know) and they definitely hold 40+ each. This weekend we made several trips between the marina and our camp at Pilot Rock, a run down past Havasu Palms, a trip to Sandbar including some high speed passes through Speed Alley, and another trip up past Park Moabi. Still was reading 1/4 tank on one side and about 1/3 on the other. That's with a motor that's much more thirsty than a 500hp. Definitely take yours in and have them check the tanks and plumbing.
-brian

[Jrocket]

MKE - POWER:
The salesman thought the tanks were each @
25 gals. I would think that a 28FT boat would have bigger tanks than that.Theres no way you could get anywhere with that small of tanks... :confused:

[Jrocket]

Heres straight from the web sight....
28' Deck Boat
Specifications:
Length: 28'
Beam: 8'6"
Approximate Weight: 4200 lbs
Fuel Capacity: 72 gallons

[Havasu Cig]

Like others are saying, something is not right. The 500 EFI's im my Cig get great mielage. I burned much more fuel in my Mach 26 with a blown 510 than my Cig with twin 500's.
I ran from Dana point to Catalina to Newport and back to Dana point at WOT most of the way on about 100 gallons of gas during a Poker Run. I think the course was about 86 miles. I was very suprised at the low amount of fuel that was burned.

[STGP]

OK, I think I finally figured out how to post a picture. Took the boat out 2 weeks ago for the first time. Ran awsome- 65 with full tanks and 2 in the boat. [img]http://www.***boat.com/image_center/data/520/598P1010081-med.JPG[img]

[Jrocket]

Well what happened on the fuel usage?
BTW,no picture... http://www.***boat.com/image_center/data/520/598P1010081-med.JPG
[ May 15, 2003, 06:00 PM: Message edited by: Jrocket ]

[DogHouse]

Not sure if you ever solved the fuel problem, but I thought I'd let you know what I just found with the tanks in my Magic... I'm converting all the plumbing for EFI and made some new high flow pickup tubes. The old ones were about 1.5" off the bottom of the tank and cut at an angle so that the lowest depth that they could draw from would be closer to 2" off the bottom. That's a lot of wasted fuel in a tank that's only 10" tall to start with. It's clear that whoever builds the stock pickups isn't very careful. I'm not surprised after looking at some of the wiring in the engine compartment, what a mess. Looks like it was all done by a high school auto shop dropout. I have cleaned it up some but I have to say that if I ever buy another Magic, I will never let them rig the boat.
-brian

[Infomaniac]

Wow !!
http://www.***boat.com/image_center/data/520/598P1010081-med.JPG
[ May 31, 2003, 07:35 PM: Message edited by: Infomaniac ]

[MKE - POWER]

DogHouse
We discovered the same thing, sort of.
We decided to troubleshoot it ourselves.After pulling seats and stuff, we discovered the fuel fill and overflow are very close together. The problem is that the tanks are very long but also every shallow,as you undoubtedly know. If the boat is not elevated at front when filling, the fuel will back out the overflow before tanks reach capacity. Beware of that overflow vent, placed right in front of your face. Poor design.
Also don't know how deep the overflow tube penetrated the tank.
As a result, we have to fill at a station where the boat is headed up hill. Don't try this at a water level fuel dock.
Thanks for your help on this.
Mark.

[STGP]

Outofgas, as Iposted on my deck boat thread, after two days of running fairly hard I used approx. 10 gals. per hour-hope this helps.
P.S.
I have a 496 HO in the boat pictured

[Eric455]

Infomaniac:
Wow !!
http://www.***boat.com/image_center/data/520/598P1010081-med.JPG you can say that again!!! man thats a purty boat. hey info what speed will this boat do with that twinwipple motor??
eric

[Well Done]

Hey Eric......you mean this one!!!
http://www.***boat.com/image_center/data/500/213211Rear_View_In_boat-med.jpg