Engine will not go to high speed fuel oil mist blows out .checked spark arrestor ,muffler,exaust ports.

Check the air filter and clean or replace if needed. Clean or replace the spark plug. Check the in-tank filter as well (located in the tank attached to a freely moving fuel line) Also, the Stihl 2-stroke machines have a spark arrestor screen located at the outflow port of the muffler, either in the form of a bolt nozzle, or screen plate. Remove that screen and clean it or replace it if its dirty. Clogged exaust is a typical problem! All of these things are VERY easy to do, good luck!

This sounds very much like a blocked spark arrestor in the muffler outlet, or the exhaust port is blocked with carbon, remove the muffler and look up the open exhaust port for signs of carbon build up, somewhere in the muffler there will be a mesh gauze ( spark arrestor ) either clean this or remove it completley.

One of two things is happening here. One thing for sure is, the engine is NOT completely combusting the fuel/oil mixture in the engine. Your mix may have too much oil in it, the rings on the piston may be leaking, letting fuel by to the exhaust port. I would first pull and clean or replace the spark plug. If oil is coming out the exhaust, a partially fouled plug is probably part of the problem now. Check that your fue/oil mix is at the proper ratio. I would also remove and clean the spark arrestor in the exhaust port and the muffler itself if you want to keep it running.

Hi,

Great explanation, You have a blocked exaust. Either the spark arrestor is blocked, or the muffler is plugged, or you have a plugged exaust port.

The best way to figue this out is to take the muffler off and shine a flashlight into the exaust port and look for carbon build up. You should see the piston go up and down, the whole port should be open. If it is blocked, clean it out with a scrapper. Make sure the piston is in the up position before you start scrapping( to keep the carbon out of the cylinder), Then wash the carbon out with spray carburetor cleaner. Then start the engine and it should run like normal ( loud but normal). The next thing is to clean the spark arestor screen, Hold it with pliers or a vise and use a torch to burn the carbon off. Once the screen gets red hot it will cook the carbon right off.

Hope this helps

If you need further help, I’m available over the phone at https://www.6ya.com/expert/matt_8dbc24bf722649ac

Smokey 2 cycle oil will cause the exhaust ports to carbon up and plug the spark arrestor.
Remove the muffler, use a pick to clean out the exhaust port on the engine, and the muffler inside opening, then clean the spark arrestor screen, to assure yourself you are correcting the problem start the machine up with the muffler off, it should run like a charm, if it goes back to running badly when you reattach the muffler it may be clogged on the inside.


I’m happy to assist further over the phone at https://www.6ya.com/expert/gregg_78ecbb34e27be215

Target your inspection towards the 'spark arrestor screen' in the outlet of the muffler.

Overfuel or 'rich' condition
Basics to check:
1) Spark plug - brown or dark brown - OK
a) is it carbon or fuel fouled
b) is there spark

2) Muffler remove for inspection
a) exhaust screen clean or plugged
b) inspect cylinder wall/piston as the flywheel is slowly rotated
3) Check Air filter for fuel saturation
4) Allow engine to run for 5 minutes to excess fuel from muffler
5) Fuel mixture ratio: Make sure the oil mix is per your manufactures recommendations
6) If after the above the engine is still smoking and blubbering:
Adjust carb mixture screws to a 'less rich' setting
*NOTE: only move mixture screws 1/8 of a turn at a time,
and try operation before any more adjustment

I’m happy to assist further over the phone at https://www.6ya.com/expert/rolandw_c013176d62ee17ae

Most likely suspects: 1) Carbon in the spark arrestor screen. 2) Carbon in the muffler. 3) Carbon in the exhaust port.

To prevent this issue in the future you should use a 50:1 ratio for you fuel mix.

Hope this is helpful,
Dolf-

This senerio is an 'over-rich' condition, most often caused by an improper fuel/oil ratio mix, and the 'exhaust screen' or 'spark arrestor' on the outlet of the muffler is plugged. Cleaning the screen may be all that is needed to correct the problem. **Make sure this screen is clean, and operate engine for at least 5 minutes before making any of the suggested adjustments below.

Basics to check:
1) Spark plug - brown or dark brown - OK
a) is it carbon or fuel fouled
b) is there spark

2) Muffler remove for inspection
a) exhaust screen clean or plugged
b) inspect cylinder wall/piston as the flywheel is slowly rotated

Overfuel or 'rich' condition
Basics to check:
1) Spark plug - brown or dark brown - OK
a) is it carbon or fuel fouled
b) is there spark

2) Muffler remove for inspection
a) exhaust screen clean or plugged
b) inspect cylinder wall/piston as the flywheel is slowly rotated
3) Check Air filter for fuel saturation
4) Allow engine to run for 5 minutes to excess fuel from muffler
5) Fuel mixture ratio: Make sure the oil mix is per your manufactures recommendations
6) If after the above the engine is still smoking and blubbering:
Adjust carb mixture screws to a 'less rich' setting
*NOTE: only move mixture screws 1/8 of a turn at a time,
and try operation before any more adjustment

I’m happy to assist further over the phone at https://www.6ya.com/expert/rolandw_c013176d62ee17ae

guarantee exhaust is clogged maybe not muffler but exhaust port pull muffler off check screen and muffler then look into exhaust port usually rectangular port is closed down with carbon pull starter slowly to lower piston then scrape out carbon with screwdriver clean as good as possible then blow cylinder out make sure to get all pieces of carbon out reassemble should run fine

Hello edv40026:

Have you Checked the Exhaust Port and Muffler for Restriction?
From your Description it Sounds like the Exhaust Port or Muffler is Restricted with Carbon Deposits, the Carburetor Metering Pump Actuator Gap is Incorrect or the Compression is Low (Worn Rings/Cylinder).
>>The Following is a Basic Instruction File for Doing a Diagnostic on the Engine for this Problem. Any Input is Appreciated.
>>**Remove the Muffler and Make Sure the Exhaust Port is Clear.
>>If it is, then Try to Start the engine with the Muffler Off.
>>If it Starts and Runs Properly, then Clean the Spark Arrestor Screen in the Muffler or Replace the Muffler if Required.
>>The Following is a Basic Instruction File for Doing a Diagnostic on the Engine for this Problem. Any Input is Appreciated.
>>**Remove the Muffler and Make Sure the Exhaust Port is Clear.
>>If it is, then Try to Start the engine with the Muffler Off.
>>If it Starts and Runs Properly, then Clean the Spark Arrestor Screen in the Muffler or Replace the Muffler if Required.
Is the Fuel Line from the Fuel Filter Staying Full of Fuel?
The Carburetor Metering Jet Actuator is Set so the Pump Diaphram Dowl is Just Touching the Actuator Arm. These Components are Located Under the Cover with 4 Small Screws Holdong it to the Carburetor Body.
Please, Do Not Hesitate, If you Hit a Snag or this Does Not Correct the Problem, I am Here if You Require More Assistance.
Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Be Happy. Thanks.

Good Luck

Respectfully

jbridger (John)