Stihl 024AV died

[bob393]

First I want to say hi to everyone.
From what I have seen on this site it is the best out there.
This is my first post and although I have been lerking around for a while I need to ask this question.

I was using my 024AV this weekend it ran fine for about 15 min, I cut a couple of 6" trees and all was well.
I set the saw down and it died. Now it will not start! I even tried a squirt of either and it will not pop.
I pulled the plug, it was dry and it has spark, not the strongest I have ever seen but it is there.
I even managed to pull my back out from trying to start it, I'm at a complete loss,
so ANY help or ideas will be appreciated. I'm not new at this and I have done my fair share of wrenching over the years but this one has me totally baffled.

 

[pioneerguy600]

Just use a couple drops of mixed gas, try that first to rule out a carb problem or just out of fuel. If the engine won`t start remove the front muffler cover and look at the piston through the exhaust port. Many die and will not restart while hot/warm problems is a scored piston.

 

[bob393]

This one I know has a full tank of fuel and just plane will not pop.
I'll try the drops of fuel next, at least that will narrow it down to a fuel related problem which I thought I kind of ruled out with the ether test.
I can check the piston but I think that would be a worst case scenario.

 

[Chainsaw Jim]

Checking the piston should be the first step as a scored piston with low compression may not pull enough impulse vacuum to engage the metering lever in the carb which allows the fuel to wet the plug.
This problem is likely the carb needing a new kit. They stiffen up and either flood the saw out or the opposite with no fuel at all.

 

[pioneerguy600]

This one I know has a full tank of fuel and just plane will not pop.
I'll try the drops of fuel next, at least that will narrow it down to a fuel related problem which I thought I kind of ruled out with the ether test.
I can check the piston but I think that would be a worst case scenario.

The mix will ctually raise the compression and I find a saw will fire better on mix than either/quick start etc. It is very easy to remove the two screws on a Stihl muffler to take a look at the piston, much easier than removing the carb. I pull the front cover off most every Stihl saw I work on, takes less than a minute to remove those two screws with my impact gun, maybe two mins with a T27 screwdriver. The piston condition tells me a whole lot about a saw`s history.

 

[grizz55chev]

Just a note, ether has no lube, it can do damage very quick.

 

[bob393]

I tried the squirt fuel in the carburetor, no go.
I pulled the muffler and the piston has a bit of scuffing, no scoring, at the top by the rings
and doesn't even appear to have any ware in the lower skirt area below the rings.
The compression seems find to the hand, I didn't through a gauge on it though.

 

[pioneerguy600]

I tried the squirt fuel in the carburetor, no go.
I pulled the muffler and the piston has a bit of scuffing, no scoring, at the top by the rings
and doesn't even appear to have any ware in the lower skirt area below the rings.
The compression seems find to the hand, I didn't through a gauge on it though.

Are the rings moving freely in the piston , carbon can stick them sometimes?

 

[pioneerguy600]

If the saw is getting fuel then I check the spark next, have seen sparkplugs go bad, possibly fouled, tip damage or shorted out up inside the metal jacket. Try grounding the sparekplug tip on top of the cylinder, pull over quickly and check for spark.

 

[grizz55chev]

May be flooded, dry it out and try again without squirting fuel in. The choke is intergal to the air cleaner on this model and I have found that I have to hold the control switch down while trying to cold start, starts great when warmed up.

 

[bob393]

I don't see any carbon at all on the rings but it is hard to tell if they are free.
The plug looks good but I'm going to change it anyway.
When I ground the plug there is spark but it looks week to me,
I'm not really sure how strong it should be but it is definitely there.

Any one know the correct spark plug so I don't need to go searching

 

[pioneerguy600]

I use NGK >BPMR7A plugs in all my PRO series Stihl saws, they work great for me and never had an issue with one. Had some Bosch WSR6F plugs that didn`t do so well, electrode tips fell out after a short run and did some piston damage.

 

[bob393]

I will grab a new one today and continue the journey.

 

[logeeland]

I would swap the plug. It is a very cheap an easy test. You said the plug was dry? Weird, even with bad spark it should be getting wet. You might have 2 issues. Worts case is you have an ignition going bad. Oh, re gap the ignition to the flywheel and make sure the fly wheel is set correctly. Maybe a keyway let go.

 

[logeeland]

Easy gap check is to use a standard business card

 

[bob393]

I didn't get the plug today, Monday it is! Good idea and easy check the air gap, thanks.
It does get spark, I'm just not sure how strong it should be, seems OK to me..
Key way, another good thought. Ill check i out when I check the air gap.

 

[logeeland]

I am not a good ohm's person. I can never properly check an ignition. I am learning though.

 

[bob393]

Well new gaped plug, Air gap reset, Key way good, Plenty of spark and NO pop even with a squirt of gas.
I was going to check the compression but my gauge plug is to bulky to fit in the spark plug hole, doesn't clear the fins. Crap
It almost has to be compression! It just seems real strange that it was running fine and died and now will not start?

 

[logeeland]

Check vacuum and pressure?

 

[grizz55chev]

Take 5min. And pull the muffler, check the condition of the piston.