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2 stroke question

#1

K

kh0432

I'm working on an old snow blower with a Briggs and Stratton 2 stoke. The reason I'm posting my question here is because it can apply to any 2 stroke. Tried starting it with starting fluid and it ran for awhile. Now I can't get it to start at all and have read somewhere that using too much starting fluid will wash down the cylinders to the point that the compression will be too low to start. Someone said they use fogging oil to start and it has enough flammable ingredients to start plus it lubricates. Any thoughts?


#2

cpurvis

cpurvis

I would think it's more likely that you've fouled the spark plug. Have you tried replacing it?


#3

K

kh0432

Not yet, I did clean it and held it against the block and can see a spark while it cranks.


#4

cpurvis

cpurvis

If you put your thumb over the spark plug hole when you crank it, can you feel compression? If you think the oil is washed off the cylinder walls, you can always put a shot of oil in the cylinder and crank it without the spark plug.


#5

K

kh0432

I have compression at the spark plug hole and can feel suction at the carburetor.


#6

Russ2251

Russ2251

Really not a good idea to use starting ether in a 2 cycle engine.
On (at least) 3 occasions I have witnessed this 'stuff' blow both seals.
Better to place about a ½ teaspoon of gas in plug hole for an ignition test.


#7

B

bertsmobile1

Using starter fluid to start an engine is wallpapering over a crack.
The carb needs some work, or the crankcase seals are gone or the rings are gone.

Starter fluid used in excessive amounts will wash the oil off the cylinder walls but 2 minutes of running will replace it.
The actual seal around the piston is done by the oil so if you spray carb cleaner down the plug hole for 2 minutes & and yes I have seen some one do this, then the walls will strip and you loose compression.


#8

K

kh0432

Here's a follow up to my original question. Finally fixed the starter for my snow blower and went to start it. While cranking I sprayed fogging oil into the carburetor and it started. Smoked a lot but that was also due to an incorrect gas mixture and too rich of a carburetor adjustment. Thanks for all the input, from now on i'll only use starting fluid on 4 strokes.


#9

B

bertsmobile1

Starting fluid is meant to be used on diesel engines or in freezing temperatures where the volatile elements of the fuel can not vapourise.
Only gasses burn so if there is no gaseous fuel in the cylinder the engine can not start.

It is too strong for most 4 strokes with a flash point that is way too low.

Back to your engine.
Do a compression test on your engine cold.
The spray some fogging oil down the plug hole, turn the engine over a few times slowly then take a second set of readings.
If the wet is 10% or more higher than the dry readings the rings are shot.

As a very rough guide, if you do the same test a week latter but spray the oil down the carb so it goes into the crankcase.
Again a higher reading "wet" indicates that the seals are gone.

Another symptom of bad seals is an engine that is very hard to start cold but start really easy when hot ( seals are wet & sealing properly ) .


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