Last updated on February 17th, 2019 at 08:03 pm
Many pilots refuse to carry out maintenance on their paramotors. They may take them to their local mechanic, or even hand them over to the capable hands of a motorcycle repair shop. These options are OK, but they can get really expensive.
Paramotors are actually really simple to maintain. So in this post we'll look at everything you need to do to keep your machine running happily, without hiring the help of anybody else!
Paramotor maintenance: Servicing and maintaining the engine
Paramotor engines have a pretty good life. They're not highly stressed, they're breathing super clean air, and they're running at a fairly low RPM most of the time. This means that paramotor engines require very little maintenance, and most can be run for 25 hours between each service.
Paramotor servicing should happen at regular intervals, so the first thing you'll need to do is fit an hour meter to your engine. These are also handy to time your flights, or to keep track of how many hours you're putting on your wing.
Next, you should keep your engine clean by wiping away any dust or exhaust spooge. Do this after every flight so that you can easily see anything out of the ordinary, like leaking gaskets or cracks.
Every 20 - 25 hours
I like to change my spark plug every 20 hours. Although they'll usually last much longer, I did once have an engine that would suddenly eat spark plugs with no warning. The engine would be running perfectly, and then just suddenly cut out!
When you change your spark plug, be sure to check the colour of the centre and ground electrode. You will be aiming for a mid brown colour, this will indicate a perfect fuel/air mixture. A weak mixture will be indicated by a very light, and sometimes white colour; this needs correcting immediately, as it can lead to melted internals.
Before putting the new plug in, check that it has the same lettering as the one you took out. And also check that this code matches the manufacturers recommendation in your manual. These letters indicate things like the thread size, reach, and heat range of the plug. If you get this wrong, you could once again end up with a melted piston.
If your paramotor has a belt, then you should check the tension, and tighten it if necessary. If you let the belt get slack, you'll loose power as the belt slips. This could be very dangerous, especially during launch, as your climb rate will be reduced. A slipping belt will also wear out very quickly.
Be careful not to over-tighten the belt, as you'll put stress on the bearing. The correct belt tension for your specific paramotor will be found in the user manual.
Oil the throttle cable
A dry throttle cable will wear out and break much sooner, it's also more likely to stick. You'll want to do everything in your power to reduce the chance of a jammed throttle, as this is the cause of most prop injuries.
With the engine switched off, a few spots of regular motor oil on either side of the cable as you operate the throttle, should be enough to work the oil into the cable. If you find the oil doesn't travel inside the outer cable, you may wish to buy a cable oiler that will force the oil through.
Clean the air filter
Not all paramotors have an air filter, some have an empty air box, simply to silence the induction noise. But if your paramotor does have an air filter, you'll want to give it a clean during this service.
Most pilots won't find much dust in their filter, as most of the time the engine is sucking in very clean air. But you may find lots of bugs, and an oily goo that is thrown back out of the intake as the engine runs.
Simply clean the filter with filter cleaner, and apply filter oil before putting it back in. If you find that the filter is damaged or that it has lost its elasticity, then it should be replaced to prevent anything being sucked into the engine and causing damage.
You should already be checking nuts and bolts during your pre flight checks, but it's worth having a run over every bolt to check that none are vibrating loose.
As mentioned in my tips and tricks post, a great way of making these checks quicker is by marking your bolts. You'll need some Dykem Cross-Check (link to Amazon), and you simply put a blob across each nut and bolt, so that you can see if it's loosened. This means you'll be able to run a quick visual check, and you won't need to check each nut and bolt with a spanner.
Every 100 hours
2-stroke engines can have some very unique problems that may be hard to diagnose unless you know what to look for. Although an engine will last much longer than 100 hours, it's worth checking a few things at this stage.
Piston and rings
Due to their poor lubrication, 2-stroke pistons will need replacing frequently. Vittorazi make the Moster engine that I'm currently flying, and they recommend replacing your piston and rings every 100 hours. Although I do recommend following manufacturers advice if you're unsure, it's not always necessary.
My engine has passed the 130 hour mark and the piston and rings are fine. But how do you know if they need replacing? When a piston and rings are worn out, you will notice a drop in power, the engine will produce much more smoke than before, and the jetting will appear to be rich (black spark plug at 25 hour check, but not always a sign of worn piston and rings).
You will also need to test the compression of the engine with a compression tester. If you buy your paramotor brand new, it's worth testing it immediately before flight, so you know what a good reading is.
If you don't know what it should be, you should be able to find out from the manufacturer. But as a rough guide, 125 cc engines will usually read between 150 - 200 psi, and 200 cc engines will be around 175 - 200 psi. If the compression test reads anymore than 20 percent lower than the baseline, the piston and rings will need replacing.
Get yourself an accurate compression tester like the fantastic offering from motion pro, that you can check out on Amazon here > Compression tester.
Neglecting these tests and running a worn out piston and rings can lead to a catastrophic engine failure that will destroy your engine. Pistons can break, as can the rings! You can also cause unnecessary wear as the piston is forced to slap around inside the cylinder.
The sorry looking piston in the picture above was removed from one of my 2-stroke dirt bike engines (the same as a paramotor engine) many years back. I had changed the piston, but neglected to change the little end bearing (right). If you change your piston, change the little end bearing, and check for up and down play in the con rod.
The reed valves loose tension over time, so they should be replaced every 100 hours. At 50 hours, you should also check them for chips around the edges, and cracks across the petals.
If the reeds are broken the engine will be very hard to start, and the jetting will appear rich.
If any part of the exhaust is clogged with carbon, the engine will loose power and run rich. We discovered HERE that using cheap oil can cause carbon to build up super fast, but even premium oil will cause some carbon buildup.
So every 100 hours of use, decoke the expansion chamber and the exhaust port. You may also wish to remove the cylinder head and clean the combustion chamber, as carbon will also collect there. If you remove the cylinder head, bare in mind that you will need a new head gasket, as they can only be used once.
The silencer will also collect carbon, so remove the perforated centre tube and clean it. The packing (silencing material) will also get full of carbon, and should be replaced.
Making carburettor adjustments
Unfortunately, jetting a 2-stroke paramotor is not just a case of set it and forget it. To get the very best out of your engine you should learn the basics of jetting. Be very careful making carburettor adjustments, as a very small adjustment could mean the difference between the perfect setting, and a melted piston.
Another thing to be aware of is prop injuries. Pilots have made adjustments which have caused their engine to rev up on starting. This spins up the prop and flips the paramotor into the pilot, usually ending in serious injury.
If you make adjustments be very careful when starting the engine, and always fit a safety strap as explained HERE.
Maintaining the frame and harness
Paramotor maintenance doesn't stop at the engine. The frame and harness won't require much maintenance, but everything should be checked before each flight.
Frame and cage
- Check every millimetre of the frame, and look for hairline cracks, especially along the welds. Frames can be re-welded if you're competent with a welder, if not then take the frame to a qualified welder.
- Check all mounting points, and use Dykem crosscheck to mark the nuts and bolts to make these checks quicker, as with the engine.
- Keep cage netting in good order, and if it gets damaged don't fly until it's fixed. Most manufacturers will supply netting if you give them a call.
- Check all buckles for cracks, and make sure all click lock buckles fully latch, and stay locked with a good pull.
- Check the carabiners for damage and cracks, make sure they latch as they should, and replace them every 500 hours. If you use aluminium carabiners bare in mind that a scratch can easily turn into a crack, so replace them with safer stainless steel carabiners.
- Check the swingarms for cracks, and make sure the bolts are tight.
- Check all material and nylon webbing for wear, and check the stitching.
This covers a few of the checks that should be done before each flight. A full printable checklist is included in my eBook HERE.
These tips should help you to keep your paramotor running happily! Thanks for checking out paramotor maintenance. If you want to avoid some of the problems mentioned in this post, be sure to run a quality oil. Check out the pilots top oil choices, and an explanation of what to look for HERE.