Stihl 051 AV help!

[zackman1801]

hey guys, so here is the story. im at my grandfathers and im wandering around the garage, and i saw this saw. its been sitting there for quite a few years because something went wrong with it and my grandfather really could care less about fixing it. So im trying to fix it up. But i dont know where to start or whats wrong with it. Its got a brand new bar and chain on  it so it would be a shame to waste. I looked over the cosmetics, it looks good, not much wear on the outside, the air filter is dirty. i havent been able to check on the cylinder to see if its scored yet because i havent been able to get much of anything off of it since my Scrench wont work since the nuts are slightly too small for the regular stihl side of the scrench and too big for the husky side.  I also havent been able to get the spark plug out because i dont seem to have a wrench big enough for the plug. The engine seems like its not seized up either because i can pull the starter cord. its got a pretty hefty pull to it. I tried putting new gas in it, and pulling it over, no luck. So what should i check for and what should i know about these saws. this thing is an absolute brute. it would be a shame to waste such a big powerfull saw when i can fix it up and use it.
Also i am under the impression that this is around a 90cc saw. is this correct? if it is what abouts is the biggest bar i could put on it. im very interested in using this saw to work with when some of my smaller saws cant get the job done.
thanks
Zack

[thecfarm]

I'm not much for working on my saws.But the fIrst I would do is pull out my tool box.You must have american and metric wrenches that will fit.Get a new plug for it,check for a spark,put some starting fluid to it and give it a try.Clean up the air cleaner too.Probaly the line from the gas to carb is gone by now.All that rubber stuff drys up and cracks.If it does start give it a real good cleaning.Good luck.

[leweee]

051AVE

[mike_van]

Starting fluid [ether] is one of the fastest ways to ruin a 2 stroke engine - Better to get the right gas oil mix, spray some in the carb.

[Al_Smith]

 A typical scenerio of an old saw in the barn .Typically the thing refused to start one day and got stuck off in the corner as punishment for laying down on the job .

Normally what person will find is a tank full of smelly gasoline ,a plugged carb with the diaphragms as hard as a rock and rotted off fuel lines .

Well you have fix all that before it will putt,no sense doing a half-fast job because you are just going to have to do it again .

Some times you get lucky and they light right off but usually it's about half a day of fiddling around  before you ressurect one back to life .

I have yet to find one I couldn't get running eventually but I've been frustrated more than just a few times I assure you .

[zackman1801]

my grandfather is really not sure whats wrong. but when he took it to the saw shop they sent it back and told him we cant get it to run and its probably not worth fixing. but in this day and age when a saw that size costs 800-1000 bucks its really worth putting a hundred bucks into it to get it fixed. its a beast, i looked at the fuel lines and they seem to be in tact from what i can see. i asked my grandfather if the cylinder and piston were shot and he said no, they were in good condition when they looked at them, so my question is if the cylinder is not shot what could be so big of a problem to scrap a saw? Also i was told that you can no longer get bars and chains for this model....is this true? if so then i guess maybe getting it fixed wouldn't make any sense. But what im concerned about is having to replace the carb or something that they might not make any more. when i found the saw it was empty of gas, but the oil tank was full, so maybe that means it was stored dry, which would help. Im really just hoping that if i take it to the shop at some point that they are going to say the same thing. but i really cant imagine what is so wrong with a big saw like that, that would make it unfixable. Even if the motor was shot i saw a full cylinder and piston on Ebay last week for $60 and shipping. Also what kind of spark plug do these things take. i cant seem to get the one i have off. i couldent find a socket the right size. they are also in a very had to reach area.  Plus can anyone tell me what the small button next to the throttle is? is it a manual oiler? if not what is it? its very easy to push in and stays pushed in untill you let off of the throttle.
Also does anyone use saws like this for work anymore? is it safe to use them for real work? and if so how do i get around the OSHA regs about having a saw with a chainbreak on it, this thing dosent have one.

[Kevin]

what kind of spark plug do these things take

Should be a ngk BPMR-7A

how do i get around the OSHA regs about having a saw with a chainbreak on it,

I don't think you would want to considering it's for your safety.

The 51AV should have had an automatic oiler unless it's an AVE or AVEQ.

Not sure about the button unless it's a safety for the throttle.

[Al_Smith]

 Well,you do what you feel is safe about the chain break deal .On that subject however a lot of us old timers ran them long before they were manditory and never had a problem . Also on that subject I question just how much good they actually do but that subject is open for debate ,I'm sure .Most people get injured by not adhering to established  safety practices not by lack of a chain brake .

[Rocky_J]

A motor needs three 'systems' working in unison to run. You need fuel (gas and air in the right mixture), compression and spark. If you have good compression then that leaves two systems to diagnose, fuel and spark. With a saw sitting for that long then a carb kit and new fuel lines would be reasonable. For spark, those old saws had points ignition so you need to deal with that. I'm too young to have messed with points, electronic ignition became popular when I was a teen.

[Al_Smith]

This got my curiosity up ,so I looked it up .The 051 shows both a points type ignition plus a solid  state type triggering device . In other words an electronic type of points with no mechanical parts ,kind of like the type used on GM products during the 80's ,if that would help explain things .

If this old saw has spark,then the problem is somewhere else  .If not,fix this portion first .

[zackman1801]

yeah now i got to find a socket to get it off, its very hard to get into the spark plug because its stuck in right under the throttle recessed into the plastic, its really hard to get a socket on their square, and the ones i suspect will fit are too wide around the outer diameter to fit into the hole. so ill have to find some creative way of getting to it, but ill make sure to check it, that was going to be my first thing to check but the lack of a socket small enough kind of killed it.

[mike_van]

The 2 part screwdriver wrench or 'scrench' that came with the saw is made to fit the plug if your grandfather has it laying around - On the chainbrake, unless you're on a job with enough employees, OSHA has nothing to say about what you do - I own six saws right now, use some everyday, not one has a chainbrake. I just like the older saws, just my preference. To me, it's what you feel comfortable or confident with.

[zackman1801]

i dont think that he has the scrench laying around. the saw is more than 20 years old, i dont even know if he bought it new.  first thing is i need to get to my grandfathers to check the saw again, its not at my house so i cant look at it right now.

[jokers]

Zack,

If you want to fix this saw up for the sake of nostalgia, then a little time and money put into it just to be able to say "it runs" might be worth while but there is a reason that this beast and other saws like it are obsolete. First, the comparative lack of performance for it`s displacement and weight, second, the lack of a chain brake, third would be poor antivibe which is compounded by the fourth factor, the horizontally mounted cylinder which is going to make the saw transfer most of it`s vibration right back into your hands. Fix it if that is your heart`s desire but let it be a mantle piece and do yourself a favor by getting a modern saw that is more reliable and easier on your body.

[zackman1801]

id love to get a more modern saw but i cant really foresee myself getting 900-1000$ to spend on just whatever anytime soon.

[Al_Smith]

 Well now ,yes some of those old saws are indeed obsolete and not worth try to use. On the other hand some of them are timeless and will hold their own even with a modern saw . This however is not one of those .

That thing is a torquer ,lots of power but heavy and slow in comparrison to a modern saw .

Trust me because I have a shed full of those boat anchor types which spend most of the time on the shelf . Some of them will indeed hang with the best of them but are  heavy,noisey and not nearly as user friendly as their modern counterparts .Fun to run on occasion but not for dailey use .

[jokers]

Al, I like your response as you`ve covered all the bases. A big old Homelite or Mac that rip snorts it`s way through a log can be endearing even if they are heavy, loud, and shake like a dog trying to pass a peach pit, unfortunately alot of the old iron just doesn`t have that character.

Zack, what is your big saw now? What do you normally cut? I see that you`ve posted your age as fairly young to be using a saw professionally, it`s my opinion that you can`t afford not to spend the coin to get a modern saw that won`t shake your fillings out and give you white finger if you`re really going to be using it much.

Truthfully though you`d be much better off with an 064 or a Husky 288 if you need a big saw and don`t have alot of coin.

[zackman1801]

right now im using a husky 365, its nice it gets the job done well, but i can imagine the time it would take for that thing to tackle some of the trees ive seen at my grandfathers house. some are 36+" DBH. thats a decent size tree for around here. i dont use my saw professionally yet, but im hoping next summer to have a job with a contractor. i cant work during the school year, i dont have time and not much logging is done after 3-4pm by the time im out of school. not to mention the fact that i like to play sports. but in any case i probably wont be able to do this anyways. it seems im going to have other financial obligations to fullfill before i have any money left over to spend.

[Al_Smith]

 If that old duffer will run I'll tell what it would be good for ,a stumper .

These old side exhaust saws that have a lot of torque make excellent stumpers .You don't have that front mounted muffler to blow chips and fumes all over you .They can take more heat for some reason and they have a lot of grunt .That old goat is what,90 some cc's

According to my info 5.8 HP at 7,000 rpm with max torque taken at 5,000 a Clydesdale of a saw .Perfect stumper .

[ksu_chainsaw]

The spark plug takes a 19 MM socket or scrench.  Any stihl dealer will have a scrench that will fit it.  I have an older 041 Farm Boss that runs when it wants to, and the spark plug location sounds similar to yours.  I used to have a home-made spark plug socket for the saw, a large nut welded to the bottom half of a 19MM deep well socket, but I lost it somewhere.

Charles