Electric Outboard – Petrol/Diesel Outboard Comparison

This is a guide for people looking at the 2 main options for outboards, including the pros and cons for each option and what to consider before buying. Please note we see this very much as an individual choice as there is no right or wrong for either solution.

Pros – Electric Outboards / Pod drives etc

  • No need to service
  • Far more reliable
  • Silent
  • No smell of fuel
  • No pull starts
  • Better for watching wildlife
  • No emissions
  • No concerns about bad fuel
  • No moving parts apart from the propeller
  • No impeller so no worries about overheating
  • Easy to use and far easier to start 

Cons – Electric Outboards / Pod drives etc

  • Up front investment is higher
  • Lack of bigger engines (over 15hp)
  • Not as many brand options
  • Range (depending on brand and budget)
  • Fewer dealers to speak to for advice
  • Some engines require heavy external batteries
  • Most don’t give a high top end speed

Best for – Electric Outboards

  • Tenders / cruising
  • Sailing boats up to 6 tons to reduce tacking and getting in/out of marinas 
  • Crossover boats such as the Xcape 4.0 kayak/ tender
  • Fishing in lochs, lakes or rivers
  • Work boats as far less to go wrong
  • Hire boats due to ease of use and no gearbox worries
  • Where the range needed is sub 30 miles for tenders, sub 120 miles yachts 
  • Backup engines due to reliability
  • Most sailors like silent running so often used along with sails

Watch for – Electric Outboards

Due to the length of time you will own it, the 2 main considerations are:

  1. Power so that you can push against the tide and/ or currents
  2. Range so that you can go further / recharge less often

It is strongly recommended that you use a minimum of 3hp and 1kw or higher as this will give over 20 miles in a tender or push a 1 ton boat between 6-9 nm so it is perfect for a backup outboard and cruising in your SIB.

When buying an electric engine most people use them far more due to ease of use and reliability. They last far longer than a petrol engine so our advice would be to buy the best you can as you will own it for the rest of your life or at least until you retire from boating.

Pros – Petrol engines / diesel inboards

  • Greater choice of HP available
  • No need to recharge
  • Far better for speed and longer trips
  • Fuel tank can be refilled quicker than charging
  • Some people love the smell of 2 strokes
  • Big 2nd hand market
  • Far more dealers to speak to
  • Less upfront cost
  • Currently the only practical solution for very heavy boats

Cons – Petrol engines / diesel inboards

  • Noisy compared to electric engines
  • Reliability
  • Often hard to start especially pull start versions 
  • Concerns over E10 fuel
  • Servicing costs and time taken to get it done
  • Not great if not used for a long time
  • The need to throw old fuel away or add stabiliser
  • Cost of petrol
  • Need to wait before going from forward to reverse or you damage the gearbox
  • Have an impeller and failure of this is costly

Best for – Petrol engines / diesel inboards

  • Boats that need a higher speed than 15 knots
  • Very heavy boats
  • Where charging can be an issue and hydrogeneration is not enough
  • For longer range – this is very dependent on the boat and solution so worth checking if electric will work
  • Where a 2nd hand engine is an option

Watch for – Petrol engines / diesel inboards

  • Some engines have bad power to weight ratio such as the 8-10hp –  they are as heavy as 15-20hp so are hard to lift.
  • Check if the engine can be used where you plan to have your boat as many inland waters have or will be banning combustion engines.
  • Engines that have not been serviced. It is amazing how many engines have been fully serviced but the owner can’t produce any receipts even for parts.
  • Where possible add a water separator and don’t use the E10 fuel. Though most manufactures say on the newer engines it is fine, the petrol does go off quicker hence adding to expense and hassle for some owners.
  • Reliability is never going to be as good as an electric engine but copies of leading brands are far worse.
  • It is strongly recommended to stay with brands like Yamaha, Honda, Suzuki, Mercury / Mariner, Tohatsu, Selva, ie proven and hold the value far better than cheap copies that also have limited dealer support. 

 

Now the really interesting bit – the torque

Let’s talk a little bit about how electric motors and petrol or diesel engines send power to the wheels. The main difference is immediate power and torque. An outboard / inboard manufacturer can say that one of their engines has 50 horsepower, but that’s actually peak horsepower. That number is the highest amount of power the engine can deliver at a certain number of revolutions per minute (RPM), and that number is usually pretty high on the tachometer.

The downside of petrol/diesel inboard and outboard engines is that they must build RPMs through acceleration until they reach their maximum power and torque. Not very efficient when you think about it! This also necessitates transmissions with several gears that optimise power output at different engine speeds.

In contrast, switching on an electric outboard or pod drive is similar to turning on a light bulb. A bulb turns on immediately when you flick a switch; it doesn’t need time to build up power. The peak power of an EV is always at zero RPMs, i.e. as soon as you turn / push the accelerator.

How we use petrol outboards / inboards compared to electric outboards and pod engines

Due to the way torque is delivered, the way we operate the engines is very different.

For many users of petrol engines, we rev the engine and then throttle back to get the boat moving. This is good for a petrol engine when it starts as it gets the fuel flowing through the system and small partials or rubbish in the fuel get flushed through. For carbed / injection engines it is also a good test that it is working well i.e. that it is not suffering fuel or cooling problems like partially blocked carbs or injectors, leaky fuel lines (we do believe the E10 scare stories are by far exaggerated), the fuel has gone off, there is a good stream of water etc.

With an electric outboard/ pod drive we do the opposite – we simply apply a bit of throttle and the boat moves. For many people this is far simpler and much less hassle. As mentioned though, electric outboards are not currently suited for boats over 6 tons or where a high constant speed is needed for a number of hours.

In Summary

Though the solutions work in different ways, both options have pros and cons and no one solution is right for everyone.

Petrol and diesel engines still have strong reasons in powering larger boats but at the other end of the scale, electric outboards offer a very strong viable option for sub 6 ton boats.

Both solutions suffer from cheap copies where reliability, build quality and, range (for electrics) is compromised.

Feedback on this page is welcome so please let us know what we should add/ remove / clarify and we will do our best to keep it updated.