5 Most Common Ryobi 4 Cycle Trimmer Problems (Plus Solutions!)

Ryobi makes a range of tools one of which is trimmers. One of their trimmer models is the Ryobi 4 cycle trimmer. We shall be delving into common Ryobi 4 cycle trimmer problems. That will be accompanied by some remedies you can use.

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What Is A Ryobi 4 Cycle Trimmer?

The Ryobi 4 cycle trimmer is a hand-held grass trimmer. Its core uses are trimming grass edges and cutting grass situated at odd angles normally hard to reach for say, a lawn mower. The Ryobi 4 cycle trimmer can also be used to do final touches on grass cut by other means. There are some problems when using the Ryobi 4 cycle trimmer though.

Ryobi 4 Cycle Trimmer Problems

The Ryobi 4 cycle trimmer is a mix of several systems e.g. mechanical and electrical. No wonder sometimes complications may arise. Some of the common Ryobi 4 cycle trimmer problems are:

1. Trimmer Not Starting

It often occurs that your Ryobi 4 cycle trimmer may not start. Such a problem needs you to properly diagnose it in order to rectify it. Some of the probable causes are:

  • Spark plug may be dirty or worn out.
  • Engine could be flooded with fuel.
  • Fuel line could be blocked.
  • Air filter could be dirty or clogged.

Troubleshooting Trimmer Not Starting Problem

When your Ryobi 4 cycle trimmer fails to start, try again. If it repeatedly refuses to start then there is an issue. Do some checks especially around the fuel system. Some of the remedies to this problem are:

  • Cleaning or replacing spark plug.
  • Removing excess fuel.
  • Cleaning or replacing fuel line.
  • Cleaning or replacing air filter.

2. Trimmer Head Not Spinning

When you start your Ryobi 4 cycle trimmer it may switch on normally. However you may then notice that the trimmer head will not be spinning. Probable causes of this problem are:

  • Dirty and or worn out clutch assembly.
  • Drive shaft may be broken.
  • Trimmer head may be faulty or worn out.
  • Throttle cable could be broken.

Troubleshooting Trimmer Head Not Spinning Problem

Once you notice this problem on your Ryobi 4 cycle trimmer, conduct some checks on the trimmer head. Do this also for the immediate components connected to the trimmer head. Once you have an idea of the root cause then you can try out the following:

  • Clean or replace clutch assembly.
  • Replace drive shaft.
  • Fix or replace trimmer head.
  • Replace throttle cable.

3. Trimmer Is Stalling

When operating the Ryobi 4 cycle trimmer, it may start well. Then it can abruptly stall. This can continuously happen as you keep switching it on again. Your Ryobi 4 cycle trimmer stalling could be caused by:

  • Spark arrestor could be clogged.
  • Carburettor may be clogged.
  • Fuel filter may be clogged.
  • Air filter may be clogged.

Troubleshooting Trimmer Is Stalling Problem

This problem is overall mostly a function of accumulation of dirt in key components of your Ryobi 4 cycle trimmer. Major culprit is usually leaving fuel inside your trimmer for too long unused. Thus you need to find out which areas might need attention. The solutions to explore here are:

  • Clean the spark arrestor.
  • Clean the carburettor.
  • Clean air and or fuel filters.

4. Trimmer Does Not Reach Full Speed

When operating your Ryobi 4 cycle trimmer there will be times you need it to run on full speed. It may occur that the engine may not reach full speed. This is a common problem that can be caused by:

  • Dirty air filter screen.
  • Faulty or worn out spark plug.
  • Dirty spark arrestor screen.

Troubleshooting Trimmer Does Not Reach Full Speed Problem

Usually the problem of your Ryobi 4 cycle trimmer not reaching full speed tends to be linked to stalling as well. Regardless you have to thoroughly check where the issue could be coming from. Possible solutions to the problem are:

  • Clean or replace air filter screen.
  • Replace spark plug.
  • Clean spark arrestor screen; often gets dirty from soot build-up.

5. Line Is Not Advancing

This is yet another common Ryobi 4 cycle trimmer problem. When the line will not advance you must do some inspections mainly on the line. Probable causes of the problem may be:

  • Engine may be too slow.
  • Line could be welded to itself.
  • Line could be tangled on spool.
  • Line on spool may be too short.

Troubleshooting Line Is Not Advancing Problem

Do not be too ruffled when your Ryobi 4 cycle trimmer develops this problem. Just do your checks to figure out what the issue is. The possible solutions you can implement are:

  • Ensure engine speed is sufficient enough; full throttle preferably.
  • Replace the line.
  • Put more line.
  • Pull and or rewind the line.

How To Avoid Ryobi 4 Cycle Trimmer Problems

Ryobi 4 cycle trimmer problems can be effectively avoided by inspecting the trimmer before and after every use. That way you will immediately fix anything that needs attention. It is also important clean the trimmer after every use. Regular maintenance and servicing are central to keeping problems away from your Ryobi 4 cycle trimmer.

What Is The Difference Between 2-Cycle And 4-Cycle Trimmers?

For a 2-cycle (or 2-stroke) trimmer, rated power is produced by the piston moving twice. As for the 4-cyle (or 4-stroke) trimmer, rated power is produced when the piston undergoes 4 cycles. Piston cycles vary depending on design. As in, it may be laterally or vertically.

Should I Choose The 4-Cycle Or The 2-Cycle Trimmer?

Depends on your needs, power or durability? The 2-cycle engine is best in terms of power. 2-stroke engines depreciate sooner though. This is because they operate at higher RPMs. However, they are less sophisticated thus easier to fix when malfunctioning. The 4-cycle engine though less powerful has more durability since it operates at lower RPMs.


The Ryobi 4 cycle trimmer is a reliable hand-held grass trimmer. Make sure you internalize the user manual so that you use your trimmer responsibly. When you have any issues you are unsure of, engage professional technicians to assist.