Stihl 031AV starting problem- Mega Fire?

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Join Date: Jan 2010
Location: indiana
Posts: 3
elbo46 Is a newbie

Question Stihl 031AV wont start
Compression is 125PSI I rebuilt the carburator because it has been recently been purchased and have no histroy on it. The spark was inconsistent so I think the condenser is bad for I checked the points through the inspection plug holes in the flywheel to check points and looked good and were set at .016" and i cleaned the contacts put in a new plug and tried 2 more plugs and still it won't start. I put a little fuel mixture into the cylinder and it won't even try to fire. I had checked the fuel line ,filter everything looks good and clean.The impulse hose that hooks to the bottom of carburator just barely pushes up onto fuel barb but I have no fuel leaking out.I have had the carburator apart Three times checking it but nothing seems to change...Still not even trying to fire. I bought a mega fire electronic conversion kit but cannot get it mounted to the armature and get the side cover back on. Has anybody tried putting on of these on the 031av before and have any luck? Thanks
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125 is a little low for these saws..

Have you pulled the muffler and looked inside???

How have you tested the spark???

How soft is the fuel line in the tank????

031av wont start

Yes, I took the muffler off to clean it and it was fine with no restrictions.The fuel line is a little soft so I put fuel mixture into the cylinder and it should at least cough a little sensing some fuel but does nothing so I assumed the spark was breaking down so I was trying to install a mega fire conversion to electronic ignition but I am haveing a time trying to get it mounted so the cover can be installed without hitting anything. I connected the + terminal to engine to ground and the - terminal off the module connected it to the white wire I clipped to the coil which went to the points. I am hoping this will fix the inconsistent spark, if not I am about ready to throw it into a catagory of maybe good for a small boat anchor and get another saw.

When Southbound said "remove the muffler and look inside" I am sure he meant to look at the front side of the piston for scoring, alumininium smearing and signs of seizure. I have had 125psi from seized saws just by putting WD40 down the bore and pulling the saw over.

If the piston looks bad then it is time to pull the jug off, clean with Hydrochloric acid on the aluminium deposits, lightly hone with 300 wet and dry and a new piston.

If it looks ok then good.

Usually I check the compression, 150psi is good, then the spark and if you have these then pull it over 10 times on full choke and check the plug gets wet with fuel.

If you have all three then the saw usually gives in and starts - check the piston exhaust side and let us know what you find - it could be a broken or gummed up ring.
Good luck
Spud

Not sure about a mega fire module but many users have put Nova modules on them. Do a search on here and you'll find some information about them. I have not used one before but others have.

031av starting problem mega fire

I took the muffler off and it was clear with no restriction, the rings look clean and free and no score marks or anything. The piston has no marks at all, I am still trying to get the ignition wired up to bypass the points and condenser.Who sells the Nova module? I might try one for I am have trouble getting this Mega Fire to work. Thanks for the help. I am going back to the shop to try again.

do tell how this works out for you. i have an 031 as well and would like to have an alternative ignition option should the factory ignition fail.

Some reading....

Stihl 031 AV ignition

031AV condenser fix / solution

Stihl 031av Help!

Stihl 031 trigger module

031av stihl ignition conversion

Thinking of conveting my old school 031av to electronic ignition.

031av

Now I have no spark at all this mega fire worked and had good blue spark turning it over with a cordless drill, started putting it back together and now no spark again even with the kill switch unplugged. I tried to test the coil when I had it off but I could not find any information on the ohm readings it should have. I hate to put a $90 coil on if this one checks out. I am going to put this mega fire on another engine in the shop just to see if maybe it might have gone bad, after all it did work for about 5 minutes and most of the things from aftermarket usually will last that long ..... I would guess it was made maybe in China , not sure? The Stihl dealer wants $30 to test out the ignition system, after all of this trouble I am having with this ,I wander if this saw is going to be saved or not.

Oh send me the saw I'll fix it for ya I'm looking to add one to the fleet. When you where spinning with a drill where you going the right way? You can spin a flywheel to the right and have no spark but spin it to the left and you have tons of spark.

031av starting problem mega fire

Yep. Even tried it both ways. Just got another ohm meter, going back to check coil again. Thanks.

Does that have two different colored wires coming out of it? try switching them and see what happens.

sefh3 said:

does that have two different colored wires coming out of it? Try switching them and see what happens.

Click to expand...

++++1

031av starting problem mega fire

Looks like I need an other coil. After getting several different readings on the primary circut I discovered the small wire was broken just at the edge of where the wire was molded coming out of the housing. I don't know if there is enough wire I can get ahold of by using a dremel to remove the plastic housing to get another wire soldered to make a connection or not. I don't know if anybody else has tried it or not, but when I stick the probe into housing to get a reading on the ohm meter I get a reading of 1.0 which is to be a good reading. Thanks for the help everybody, I am going to try to save it. By the way I found a Stihl part # 1113 405 1901 on a post. I called a Stihl dealer in my town and he said it changed numbers and he had never sold one and would have to call Stihl because he did not know if it was still available. I will call him back tomorrow and see if he can tell me more. Thanks again everybody!!

I believe it has been done...

Ebay is a good place for parts that dealers no longer stock...

mega fire

Both wires are the same color. You can switch them around for either - or + ground so like on this 031av which has an inverted ignition you just secure the wires according to the needs of the application. I have installed several of these mega fire kits on other engines with good results. I am a Stens Dealer so I had no idea what the nova module was but after researching them on the web it looks to be the same thing with another name on it. There are two different modules available I used the Stens # 440-465 and after I found the Primary lead was the problem all along it was working only sometimes and sometimes not and giving me different readings every time I checked it and going to get and use 3 different ohm meters it was a little wire went bad all along. I was successful in taking the coil wire out and saving the coil so I could use the mega fire. It now has the hottest looking spark now like it never had before. If this lasts a long as all the other mega fires I have put on in my shop in the years past I will never have to worry about spark on this unit again, for I have not ever had one fail yet. Hope this helps. Thanks again.

Great !!!!!!!!!!!!!!!!!!!!

Sounds like you got her fixed up......

031 av won't start

I have a bright blue spark now but this thing will not start..I'm wandering if the timing could be off for I have never had the flywheel off and think maybe it might have a sheared key but I am going to have to get a remover tool somewhere. I called the local dealer but he couldn't find a number yet for me to order one. After putting some fuel mixture under the spark plug it won't even try to fire or back fire ...nothing. This saw is really be a stubborn one. I would think even if the crank seals were shot it would at least bark a little or even a small growl but no such luck.

This is the puller I used.....

031 flywheel puler

I have a steering wheel puller like that one except it will not thread into the flywheel it looks like this one might have 22 mm threads and the only other holes are for the adjustment holes for the point adjustment.