spudulike

I don't know about this coil but I have had a MS361 and a Stihl blower coil fail on the high speed section meaning revs plummeted and cut out on anything over mid revs. The revs did die rather than cut in and out though.

If the maximum disk speed is around 4500rpm then the belt/ gears must be a 2:1 step down, easy enough to work out, just mark up the disk and the drive pulley then rotate the drive pulley once and see if the disk spins 1/2 a turn. The final check is to run it for an hour and check the colour of the plug. Black is rich, tan is good, white is lean, grey is a melted piston👎. Look at the central electrode colour rather than the outer body.

I haven't really done many stone cutters TBH, they are usually shagged on so many levels as the guys that run them, have no concept of cleaning and changing air filters so the cylinder, piston, mains etc are usually shot and repair stupidly expensive. These stone saws only rev to around 9600rpm so will sound pretty flubby compared to a saw. If the machines coil is limited, my tach starts bouncing all over the place so the easiest way to tune any machine with a limited coil is to richen up the H screw, rev the machine up and keep leaning it out until the tach goes wild and this way, you can be sure the carb is limiting the engine at the same point the coil is. This always worked fine for me. If you are doing much of this work then doing this sort of adjustment with a tach is pretty critical hence this tool was one of the first I got Not much help in your case but perhaps just turning the H screw right in and then leaning it down until there is no further change then winding it back in 1/6th of a turn may do it. On the Politics...I am referring to, as ADW was, about the guys that seem to hate each other on the threads about the Labour party, Russia, Farage etc. There is now very little about repairs on this site and guys like Garden kit, ADW and myself etc just move on. Unfortunately many of the "Old School" are gone and along with them, a wealth of knowledge....just the way it is. It is refreshing to get a technical repair thread👍

ADW is fine but like many, got fed up with the "political discussions" on the site that have taken over from what was a decent arborist site with decent content where guys like us can sort out the technical issues that we deal with on a daily basis but there you go. On the K750....try 1-1.5 turns on each L&H screw, I usually tune the L by ear and the H using a tach but each man to his own.

Stihl also do a material cover for this filter, sure, it will impede airflow a bit but life is a compromise!

Your 461 and 066 will be going long after these more modern machines have clapped out. The 550 has the Husqvarna air cleaning system where the flywheel fins spin the air in to the air box so it is relatively clean before it hits the air filter. There was a vid on YouTube with a Husky and Stihl running side by side and he piled saw chip over both saws, turned them off and looked at the air filter. The Husky was remarkably clean. I would give the carb a service, new diaphragms and fuel strainer (the one in the carb) and would then get someone who knows what they are doing to adjust the carb L screw and tach it on the H screw. I have gone many and every one ran lean and was revving higher than it should. Less fuel makes the saw more difficult to start. It is worth making sure that the choke is actually completely shutting off the choke when applied and the fast idle setting is actually holding the throttle open a bit. This will show up as the saw not revving much on the mid setting between choke and idle on the choke lever. It is all basic stuff.....these saws should burp on two pulls and start on the third if cold. No saw should need 8-10 pulls or more to get it going

Try looking at a few of the YouTube vids, the guys on there test all sorts and compare power outputs and check the metal debris in the oil etc. I have Loncins on a Rover mower and chipper, both have been fine for me.

Looks like the standard carb to me, I don't think I have ever seen a copy, probably too difficult to manufacture cheaply.

Have to love customers like that. Fortunately I was pretty lucky and had very few like this👍

The 461 is a decent saw as it was pretty much a 460 with a few eco mods on it. I would check out the state of the piston/ compression...taking the exhaust off and inspection would help. I would then check out the carb and fuel lines as fuel issues made up around 80% of the issues I saw in my time. These, and 460s, used to accumulate fine wood chip around the metering diaphragm, the fuel strainer is worth checking and a final adjustment of the carb as typically, I found the H screw would be lean and the L screw needs a retune when the saws had run in well. Manufacturers tend to lean the settings to achieve a better eco setting. The limiters will most likely need to be removed for a retune.

Agree with Mark, looks like the glue is breaking down and once it does, it will block jets etc. you may not need to reseal the welch plug....try it first and if the saws idle is iffy, just use a smear of glue.....most petrol resistant glues are not truly petrol resistant.

TBH, both helicoil or Timesert will do an effective job if done correctly. One bit of advice is to use a decent quality tap and usually a taper one otherwise there is a distinct chance that the tap will go in at an angle causing sealing issues. I use Volkel taps as they are decent and not OMG expensive, avoid all these cheap Chinese alternatives as the job is as strong as the quality of the receiving thread.

Not sure if I have mentioned this set before. I have only used it a handful of times, it didn't cost more than £25 but it has made some very tricky jobs sooooo much easier. It is basically for removing any bearing that has disintegrated especially ones in blind holes. Although it was cheap, it has been stonking. The latest one was removing a disintegrated wheel bearing from the Mother in Laws walker. You insert the appropriate die inside the outer bearing race, do up the top to expand it tight then use the appropriate puller to pull the offending item out.

I would imagine scotchbrite or 400 grit emery paper would be enough and just use a little GT85 or WD40 whilst rubbing......not up and down but around the bore.

Exactly on doing it yourself, I wouldn't have expected to do too much on a two year old machine, I think I must have been pretty cheap when I was doing repairs. Without seeing it and without any broken/ damaged parts....1-1.5 Hrs should have done it with parts on top.