Trying to use an outboard motor other than gas? In this article, I wrote, what are the major differences between electric and propane outboard motors, and the comparison with a gas outboard motor.
Both of them are very good, there is some difference between electric outboard motor and propane outboard motors, and the differences are based on price, performance, speed, etc.
- Price – propane is cheaper than electric.
- Weight – electric is lighter than propane.
- Noise – propane is louder than electric.
- Top speed – both are almost the same.
- Running time – it differs from the capacity.
But, speed and running time will differ depending on the size of the boat and the weight in the boat. These outboard motors are good compared to the gas outboard motor in many ways.
1. Price – propane is cheaper than electric ones
- When it comes to the price propane is much cheaper than electric outboard motors. Because in propane outboard motor we are using propane gas as fuel.
- We are using the same process of converting fuel to rotate the propeller (propulsion system). The process of conversion is not expensive when compared to the electric motor.
- In an electric motor, we are using the stored electricity or generating electricity(with solar panels). The electric motor comes with less noise, no need for maintenance (some of them can last for 20,000 hours without maintenance), and lightweight.
- With all these benefits, the cost will increase rapidly. That is the reason why an electric outboard motor is more expensive than a propane outboard motors.
2. Weight – electric is lighter than propane
- The electric outboard motors are lighter than propane outboard motor. However, there is no big difference between them when it comes to low horsepower outboard motors (around 5 hp or less).
- These electric motors are very light and easy to handle, especially when you are tilting the motor. You can say goodbye for the back pain you will get while tilting the gas outboard motor.
- The propane outboard motors are a bit heavier than the electric motors. Check the tables below on weight comparisons between electric and propane outboard motors.
Comparison of 5 hp outboard motor weights
| Brand | Type | HP | Weight |
| Torqeedo | electric | 5 | 38.5 lbs |
| E-propulsion | electric | 6 | 49.6 lbs |
| Lehr 5.0hp | propane | 5 | 48.4 lbs |
Comparison of 9.9 hp outboard motor weights
| Brand | Type | HP | Weight |
| Torqeedo | electric | 9.9 | 40.3 lbs |
| E-propulsion | electric | 9.9 | 61 lbs |
| Lehr 9.9 hp | propane | 9.9 | 88 lbs |
In the case of 5 hp, there is only less difference between the weights. But, in the case of 9.9 hp, there is a more difference between the weights.
3. Noise – propane is louder than electric
- When it comes to the noise, an electric outboard motor is very calm compared to the propane outboard motor. 33 dB is the sound of the Torqeedo outboard motor. E-propulsion in a bit higher than Torqeedo.
- The electric outboard motor is very silent compared to all other outboard motors. It is quiet because there is no gearbox, and there are very few moving parts, which will cut down friction noise among them.
- The electric outboard motor is way quieter than 4-stroke and 2-stroke gas outboard motors. The propane outboard motor is louder but not equivalent to a gas outboard motor.
4. Top speed – both are almost the same
- Whereas in terms of speed, both the electric outboard motor and propane outboard motor are almost the same. When it comes to the range, it depends on the capacity.
Speed Comparison of 5 hp outboard motors
| Brand | type | Hp | speed (RPM) |
| Torqeedo Cruise 2.0 TS | electric | 5 | 1300 |
| E-propulsion NAVY 3.0 | electric | 6 | 2300 |
| Lehr 5.0hp | propane | 5 | 4500-5500 |
Speed Comparison of 9.9 hp outboard motors
| Brand | type | Hp | speed (RPM) |
| Torqeedo Cruise 4.0 TS | electric | 9.9 | 1300 |
| E-propulsion NAVY 6.0 | electric | 9.9 | 1550 |
| Lehr 9.9 hp | propane | 9.9 | 4500-5500 |
Although there is a difference in RPM’s, there is no much speed difference among the speed. So, both of them are almost the same in terms of speed and running time. Still, if you buy a bigger outboard motor (high horsepower), you will get more speed.
5. Running time – it differs from the capacity
I compared the running time for the outboards in the range of 5 hp to 20 hp.
Running time of 5 HP propane outboard motor
| Fuel tank capacity | Time (at maximum rpm) |
| 16.4 oz | 30 min |
| 11 lbs | 5 hrs |
| 20 lb | 10 hrs |
Running time of 5 HP electric outboard motor at max speed (with a full charge)
- Torqeedo – 01:45 hr
- E-propulsion – 01:00 hr (6 hp motor)
Running time of 15 HP propane outboard motor
| Fuel tank capacity | Time (at maximum rpm) |
| 11 lbs | 01:40 hrs |
| 20 lb | 03:20 hrs |
Running time of 20 Hp electric outboard motor at max speed (with a full charge)
- Torqeedo – 01:00 hr
Comparison between propane outboard motor and gas outboard motor
There are only a few differences between propane outboard motor and gas outboard motor.
The main difference between propane outboard motor and gas outboard motor is efficiency. The efficiency of a propane outboard motor can be comparable to gasoline motors. Each pound of propane will perform roughly the same as a gallon of gas providing similar power and range.
- There are claims that propane outboard motor can be as much as 14% more efficient than gas, but at the very least, the performance of the motors is comparable to any 2.5 and 5 horsepower gas outboard. Physical specifications are also comparable.
- Apart from the oil in their crankcase and the disposable tanks (which are 100% steel and can be recycled) propane outboard motor emissions make these truly green engines.
- The octane rating of propane is about 110, which provides for a high compression ratio (about 15.5:1, compared with about 14.7:1 in a gasoline outboard). This delivers power more efficiently to the crankshaft.
- Propane gas outboard motors are easy to start. If you left the propane outboard motor for years also nothing will happen, it will start quickly than a gas outboard motor.
Check this Wikipedia page for octane rating click here (don’t worry, it will open in new tab).
Check this popular mechanics website on the working of propane outboard motor click here (don’t worry, it will open in new tab).
Propane outboard motor: Are they worth the cost?
Let’s find out whether the propane outboard motors worth the cost or not.
Propane is similar to a gas outboard motor (for both, we need to carry fuel tanks). The propane price is almost equal to or less than the price of petrol. Even you can take propane gas from your home. Propane motors cost less and good for the environment. So, it is worth buying them.
Again, if you want high-performance stuff, then you need to go for a gas outboard motor. From the price perspective, it is worth buying them because propane outboard motors have almost the same price as a gas outboard motor. In the long run, you will get benefitted by using a propane outboard motor (propane is a bit cheaper than gas).
Comparison between electric outboard motor and gas outboard motor
- For a gas outboard motor, you need to bring an extra gas tank. But, in the electric case, it is different, because for the electric motor you can bring an extra battery (smaller in size compared to a gas tank) or you can charge it while boating with the help of a solar panel.
- If you have a solar panel, then you need to allocate some space for it on the boat for charging. That is the only problem with an electric outboard motor.
- Whereas for a gas motor we can use an extra gas tank instantly and we can go. The electronic outboard motor is very quiet when running, and of course, does not have the issues of fuel tanks like gas outboard motors.
Electric outboard motor: Are they worth the cost?
Let’s find out whether the electric outboard motors worth the cost or not.
The gas outboard motors are cheaper than the electric ones. But, electric motors are better than the gas because, in the long run, you will get benefited from it. For an electric motor, we need to charge them (it will cost less than petrol). Whereas, for gas ones, we need to buy gas every time.
- Electric outboard motors are very calm and very light. The only problem with them is ‘charge’. All these electric motors are benefited in the long run.
- You can use these electric outboard motors where you cant use a gas-electric motor. Whenever you are using them, you should bring some power source or solar panel along with it.
Check my article on Best 3 hp electric outboard motors: Are they worth the cost? (don’t worry, it will open in new tab).
From the price perspective
When it comes to the price, the gas outboard motors are way cheaper than the electric ones. But, the electric ones are far better than the gas ones because, in the long run, you will get benefited from it.
Okay, now let’s do the math. Consider the electric motor price is around 2000 dollars, for a 3 hp motor (a good outboard motor). For that same price, we will see what all gas outboard motors will come.
| Brand | model name | price | HP |
| Yamaha | F6LMHA 4-stroke | $1700 | 6 hp |
| Honda | 2020 HONDA 5 HP BF5DHLHNA | $1733 | 5 hp |
| Mercury | MERCURY MARINE–8hp 4-Stroke | $2070 | 8 hp |
| Tohatsu | MFS6CSPROUL Sail Pro 4-stroke | $1980 | 6 hp |
| Suzuki | Suzuki 6 HP DF6ASW2 | $1565 | 6 hp |
Four cycle engines(four-stroke engines) are now boasting of even better gas consumption. Many burn gas according to the formula:
Gas consumption per hour= horsepower/15 gallons/hour.
| Brand | model name | HP | consumption |
| Yamaha | F6LMHA 4-stroke | 6 hp | 0.4 gallons per hour 1.5 liters per hour |
| Honda | 2020 HONDA 5 HP BF5DHLHNA | 5 hp | 0.33 gallons per hour 1.2 liters per hour |
| Mercury | MERCURY MARINE–8hp 4-Stroke | 8 hp | 0.53 gallons per hour 2.01 liters per hour |
| Tohatsu | MFS6CSPROUL Sail Pro 4-stroke | 6 hp | 0.4 gallons per hour 1.5 liters per hour |
| Suzuki | Suzuki 6 HP DF6ASW2 | 6 hp | 0.4 gallons per hour 1.5 liters per hour |
On average outboard motor above are consuming = 1.542 liters per hour.
Assume that in one month you will use 15 liters of gas for your outboard motor. Then the total cost will be $30 per month (1-liter petrol = $2).
Then, each year you will be spending around $350 for gas on the outboard motor. And for 2 years it is $700. You can avoid this if you use an electric motor. The electric motors are good for health and to the earth.
Conclusion
Both the electric outboard motor and the propane outboard motor are good for the environment. In the future, they might take the place of a gas outboard motor. Both of them are good but, you will get a bit less performance than a gas outboard motors.
Check this website for information on propane and electric outboard motor click here (don’t worry, it will open in new tab).
Related questions
1. What fuel do outboard motors use?
These are the basic fuels, used by an outboard motor
- Gas outboard motor – Petrol
- Propane outboard motor – Propane
- Electric outboard motor – Electricity
2. Which fuel delivers power more efficiently to the outboard motor? Petrol or propane?
The octane rating of propane is about 110, which provides for a high compression ratio (about 15.5:1, compared with about 14.7:1 in a gasoline outboard). This delivers power more efficiently to the crankshaft.
3. Which outboard motor will start quickly? Petrol or propane?
The propane outboard motor will start quickly because propane will not drain like gas.
