Best fuel efficiency from carbed 2 cycles

[fishingdan]

What fuel efficiency suggestions do you have for those that have older, good condition, 2-stroke outboards? I have a 1990 Merc 150 that is in great condition. I can't justify spending the money for a new efficient engine, but I do want to run this thing in an efficient manner?

 

[LubeDude]

Re: Best fuel efficiency from carbed 2 cycles

Keep it tuned up, run it at about 3,500-4,000 RPM, Change to a synthetic lower unit lube, make sure you are set up correctly as far as the hight of the engine and the prop, make sure your prop is in good shape, and I think that the use of a synthetic outboard oil makes a very slight difference.

 

[JB]

Re: Best fuel efficiency from carbed 2 cycles

Yeah. What LD said, plus:<br /><br />Move the boat at idle or on plane at all times. The less water you push, the less fuel you burn.<br /><br />Keep the hull meticulously clean to minimize drag.<br /><br />Fine tune the rigging. . . .engine height (DHadley's "X" dimension), and engine trim for minimum throttle to maintain a given speed.

 

[JasonJ]

Re: Best fuel efficiency from carbed 2 cycles

Also run some trim tabs if the wallet allows. If you can get on plane more quickly, or can plane at a slower speed and are willing to take more time going from point A to Point B, you will use less fuel. Also, look at the big picture. Do not carry any more load on the boat than you need, weight is the enemy. If you know your trip will only be a certain distance, and you have a good working knowledge of how much fuel you use to accomplish this distance, then only carry the fuel you need. For example, I try not to run with a full tank. My fishing routine is very predictable, and I know I can get to where I need to and back on a quarter tank of fuel, so I generally fill it only halfway. If I think I might need to go somewhere else, I'll fill it up just in case. You just have to know the boat and know how you are going to use it. I get decent economy out of a 36 year old motor practicing these steps. And remember, you will never get your money back in fuel savings over the massive cost of a new outboard. You are better off with your good running PAID FOR motor, unless you just want a new motor. Good luck...

 

[bossee]

Re: Best fuel efficiency from carbed 2 cycles

Hi,<br />A fuel flow meter (fuel management, FM) could be a nice thing to invest in. Then You will see with Your own eyes how much gas the outboard consume at various speeds.<br />Navman Fuel 2100 is not that expensive.<br />I use the more expensive Navman Fuel 3100 that can be interfaced to GPS so it can show fuel economy also - Nautical mile per liter(or gal) in addition to liter(or gal) per hour.<br /><br />Up to 4-5 knots OR planing speed (18-20 knots and up to best economy speed, probably around 4000-4500 rpm) is a good rule of thumb to have reasonable fuel burn.

 

[fishingdan]

Re: Best fuel efficiency from carbed 2 cycles

Thanks for the suggestions. <br /><br />I agree with you JasonJ. If an old engine is running very well, it simply doesn't make sense to replace the engine (at least for a typical recreational boater) with a new engine given the costs.

 

[WillyBWright]

Re: Best fuel efficiency from carbed 2 cycles

Keep in mind that the bigger the wave you produce, the more gas you use to make it. Avoid full throttle except to get out of the hole, then back off to 3/4 to 7/8 throttle.