Engine Mounts

updated August 2, 2022

The rubber engine mounts on all paramotors are normal, perishable items.  That is, they have a limited life and will fail after so many hours, usually around (50) hours, depending on the size of the engine.  Some mounts may only last about (10) hours which is why it is a good idea to watch them.

If pilots replace these mounts with the heavy duty Viking PPG Poly Motor Mounts, they must be certain that the new mounts do not touch any parts on the engine.

The following Polini Thor 130 suffered a catastrophic failure of the hand starter where it separated from the motor while the pilot was in the air.

What had happened was that the pilot had installed the Viking mounts but did not check the clearance from one of the mounts to one of the starter mounting tabs.  The severe vibration of the motor caused the starter tab to start wearing down the mount.  But after a while, the forces were so great that it caused the starter screws to shear where they entered the screw holes on the engine.  Two screws sheared off and the third had its threads stripped.

The front of the Thor 130 with the starter removed showing the lower right Viking Poly PPG motor mount that had rubbed against one of the starter mounting screws.

On the Polini engines, pilots must grind down the lower left mount so that it does not touch the starter mounting tabs.  A 1/4 inch clearance should be sufficient.

Modifications to engines, in general, must be thoroughly reviewed and checked for potential problems like this one.

One thing is common to all paramotors:  They all vibrate severely, especially the larger engines.  As a result, motor mounts should be checked routinely and replaced promptly. 

Installing safety straps for the upper motor mounts is a good idea if your engine does not have them.  Walmart sells black nylon 1” belt webbing in the sewing department that can be used to make a loop that can be installed under each end of the motor mount.  Use a heated knife to cut it and a heated rod or Phillips screwdriver to burn (2) holes in it.  Attach it under each end of the mount so that it makes a loop.  The loop should be just long enough to not restrict any movement.   Pilots can also use heavy duty extra long 1/4" nylon zip ties to prevent the engine from moving away from the frame if an upper mount breaks.  The zip ties can be wrapped around a frame member and then attached to any part of the engine where they will not slip off.