Stihl 075 question.

[starsailor]

I was looking at an old (old Stihl logo) used Stihl 075AV this last weekend to setup for use as a milling saw. I was surprized to see that it didn't have a decomp valve in the cylinder head by the rear handle. All it appeared to have is a plug in the cylinder head where (I think) the decomp valve goes. Did the older 075's have decomp valves? I couldn't imagine starting this old beast without one. The saw had been through a recent cylinder rebuild and has a ton of compression. I could yank the saw up and down on the starter handle and it wouldn't drop one bit, yet I could pull it over 1 or sometimes 2 cycles if stood on the handle and I pulled really hard. This was all with no gas and the plug wire pulled off.

Am I missing something here?

I think the 075 would make a great milling saw. I'd like to buy it, but I'd like to keep my arm in the socket too.

 

[wdchuck]

I have an 075, and it's real easy to start, no sign of any decomp.

Get the piston up to TDC, then let the cord back in, then do a full yank, 1 or 2 pulls like that and it's no trouble at all, drop start mine real easy now that I do it that way. Been doing it on all my other equipment now too, makes a world of difference. Try it, your arm will be happier.

It's a good milling saw, but may I recommend extra screws, and a tiny dab of serviceable loctite on all the screws. experience talking here.

 

[computeruser]

Yeah, some have decomps and some don't. I've got one of each and don't find the decomp-less one much more difficult to start. Both of mine fire, luckily, on two pulls with choke and I can usually flip the choke off while it's sputtering after pull #2. So there isn't that much yanking going on. Still, I find my 066 (w/o decomp) and 7900 (when I forget to use the decomp) much more prone to kicking than either of the giants.

They're fun saws for the bigger stuff and great for milling, so go buy you one!

 

[GASoline71]

Yup... 076AV (Always Vibrating) Used to get it close to top dead center and it fired on usually the 2nd pull... but on those days when it thought I needed to be taught a lesson... it would just about knock my teeth out when I missed that stroke.

Gotta love the BAMFS!

Gary

 

[starsailor]

OK, guys so if I understand what you've all said, some have a decomp some don't, but yours call all be started without one. That's good news. I'm going to have another look at this saw and see if I can start it this time with spark and some fresh mix. If I can, I'll buy it to setup for milling.

I definitely remember that there's some sort of plug screw in the head though. As I recall there were 3 allen head screws surrounding the sparkplug, to hold the back case on (I think). Then this plug I'm talking about was to the right of that looking at the sparkplug. Am I correct to assume that I can likely swap out this screw plug for a decomp valve? If I get the saw I'd definitely like to add one to save the old shoulder.

As a kid I can rememeber my shoulder being sore for a week or more when my dad's big and mean Mac 250 would fight back when I was trying to start it. Dad got a big old laugh every time. I'm a lot bigger now and as strong as he was then, but I'd sure like to avoid any repeats of that experience if I can. Now that I think of it though it makes me wonder why he'd let me start it in the first place even though he wouldn't let me cut with it.

 

[wdchuck]

Something else, if the seller will allow it, and it'll take a few minutes, remove the exhaust and check the piston/cylinder, if that's good, and the compression is there, that pretty much eliminates the big $$ problems.

Disregard the above, forgot that it was rebuilt. Pulled a Homer.

Good Luck on the saw, if you get it, you'll have some fun with it for sure, it doesn't run as high rpm's as the newer saws, but it's got plenty of grunt.

 

[starsailor]

Thanks wdchuck I'll do just that, but from what it feels like from the few pulls I've already done it's got to have near new compression. The recent rebuild included rings, a light hone, and all new gaskets and seals. The seller showed me the shop invoice. Also, according to the seller the cylinder and piston were very good and nowhere near needing replacing.

I'll pull the muffler and spark plug and have a good look, probably bring my compression gauge too and measure the thing. Any idea what the compression should be for say new (after breakin), average, and minimum for this engine?

 

[Lakeside53]

You can add the decomp easily.. about $20.

Compression.. 145-155 is fine..