2000 islandia using 1 gallon of gas for every mile

[mike's islandia]

I have a 2000 islandia with a new powerhead from obr (threw a rod thru the block last summer) The new engine has about 12 hours on it, the boat is running great engine wise, pulling kids on tubes and the holeshot is fine. The problem is that the amount of gas i am going thru is WAY out of the ordinary, I am now mixing my fuel 50-1 and it is eating it up,it did the same thing when the oil pump was hooked up, I drove 9 miles and used 12 gallons of gas, i cant figure it out, the linkage seems to b ok.any help would be great i dont wanna blow another one up.I cant afford to use the boat with gas being 4$ a gallon

 

[Dr Honda]

I bought an Islandia with a thrown rod, and I'm just tarting on the project now. BUT... it's my understanding that the best fuel economy is at about 27mph... and it's only 1.8 mpg. This is very typical for a jet boat. Unfortunately... if you want good economy, you need a small engine, and a prop.

With that said... high clearance in the jet pump can show up as poor fuel economy. Have you checked the impeller, and ring lately.

 

[mike's islandia]

That would mean towing my kids for about 10 min (and we all know that happens 20 times a day)at 20 miles an hour is about $10 not counting oil, I dont expect fuel economy but i am not sure i could dump gas out of the gas can that fast, where did you get the figure of 1.8 miles per gallons? with a full 50 gallon tank i have to plan for how far i can go in a 3 hour trip counting stoping at all sand bars on the way

 

[El Toro 33809]

Fuel info:



Test Power: 1 x 240-hp Mercury M2 EFI Jetdrive
* Range *
RPM MPH Knots Total GPH MPG NMPG Stat. Mile NM** KM*** KPH*** LPH*** KPL** dBA
2000 6.1 5.3 3.4 1.78 1.55 88 77 142 9.8 12.87 0.76 77
2500 6.8 5.9 4.5 1.51 1.31 75 65 121 10.9 17.03 0.64 82
3000 7.5 6.5 5.7 1.31 1.14 65 56 105 12.1 21.58 0.56 82
3500 8.6 7.4 7.7 1.11 0.97 55 48 89 13.8 29.15 0.47 80
4000 18.5 16.1 9.5 1.95 1.69 96 84 154 29.8 35.96 0.83 83
4500 26.8 23.3 13.5 1.98 1.72 98 85 158 43.1 51.1 0.84 84
5000 33.0 28.7 18.7 1.76 1.53 87 76 140 53.1 70.79 0.75 89
5500 36.8 32.0 23.8 1.55 1.34 77 67 124 59.2 90.09 0.66 93
5800 40.5 35.2 26.7 1.52 1.32 75 65 121 65.2 101.07 0.65 97

http://www.boattest.com/boats/boat_video.aspx?id=130#Test-Result

 

[johnhibbs]

I noticed an improvement in my gas mileage after I replaced the temperature sensor on the engine (Passenger side). It also starts better when the engine is warm. That was the problem I was trying to solve but it also increased the gas mileage after I replaced it. It think it controls the air-gas mixture ratio via the ECU. I'm going to try a fuel additive called Startron this summer to see if that helps too.

 

[El Toro 33809]

John, it looks like we both have the same boat. Do you know the part number for he temp sensor and where did you get it?

Thanks

 

[johnhibbs]

The PN is 13536A14 and I got it at my local Mercury Parts Dealer. You will also need some thermal heat sink compound when you install it. Radio Shack has the compound. The manual says that the temp sensor can increase the fuel mixture by 40%. I think the sensor costs around $25 or $30. I took my old sensor apart and found out the the insulation on the wires is not nylon but probably low temp PVC and that the insulation had melted and one of the wires was touching the inside of the case. I posted photos on this web site.