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The Huztl 036 after 10 hours hard work (with home-shortened bar) |
July 2019 update
My Farmertec MS360 is still working fine, and so are several other Farmertec kit saws we've made. Since making the MS360, friends and I have made 4 Farmertec MS660s and another MS360 on our kitchen table - it is an addictive behaviour! I'm using my two 660s for chainsaw milling and I've reviewed the Holzfforma Alaskan mill in this post. The 660s are probably the easiest saws to work on (like an old car with plenty of room under the hood), very powerful, good for chainsaw milling, but they're heavy for day-to-day use. I've also made extensive repairs on Stihl 024 saws (the smallest Stihl professional forestry saw) with Huztl parts, described in my blog post here.
If you're wondering whether making a Farmertec saw kit is a good idea for you, it depends mostly on you. You need to use a bush engineering attitude: don't expect things to be perfect, be ready to diagnose and solve problems and focus on what you can learn and how to get the show on the road. These kits aren't a product for a consumer mindset. You can't waste energy being critical of the manufacturer when things aren't perfect - remember the price! I Haven't used any genuine parts on any of my saws so far, and they have done a lot of hard work for me.
November 2017
We recently made an MS360 chainsaw from a Huztl/Farmertec kit of non-genuine parts. It was fun and educational, and the saw is working well. Overall I think these kits are a great product for someone who wants to develop their mechanical skills and get a good chainsaw, at a low cost, that they know how to repair.
Choosing a saw
The MS360 is the smallest professional forestry saw kit sold by Huztl (see below for a definition of "professional" chainsaws). At 62cc it is powerful enough to comfortably run a 16" bar and cut hardwood firewood. It's a good all-rounder for someone who only wants one saw for firewood and general use. It's too small for chainsaw milling, but I find it a bit heavy for forest thinning if I'm spending all day cutting small saplings - but if you're doing either of these things you probably have a few different saws in the shed.
Repairable chainsaws
If you want a saw that can do a lot of work and last a long time, and you want to do your own mechanics, it’s important to know that some saws are more repairable and durable than others.
Some brands of saw are easier to get parts for, as well as being good quality. In Australia, Stihls are clearly the easiest to get parts for, including non-genuine parts. Husqvarna would be the second easiest, and appears to be Stihl’s main competitor for quality. In Australia, Stihl has a near-monopoly in chainsaws, with other makes being pretty unusual, with the exception of consumer saws in hardware shops, which tend not to have much spare parts availability or range of sizes, as well as most being of poor quality. My experience has been mostly in Stihl, so I prefer to stick with them.
Stihl chainsaws come in 2 distinct qualities, which are very different in repairability.
The older design type of saws, often described as “professional” saws, have a metal chassis which forms the structure of the saw. It comes in 2 cast metal halves with a vertical joint, sealed with a gasket, forming the oil tank and the crankcase, and having moulded flanges to carry the external parts of the saw. The cylinder bolts on top of this crankcase and is easily removed or replaced, without necessarily dismantling much of the saw. A worn or damaged piston and/or cylinder can be quickly and cheaply exchanged. These saws are highly repairable and, unless they have serious accidents, can have almost indefinite life expectancies. When I first bought Stihl chainsaws, this was the only type of saw they sold. However it seems that market pressure pushed Stihl to produce another line of cheaper, less repairable saws for less intense use. The professional saws are still made and sold, at significantly higher price.
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This is a typical metal chassis from a Stihl professional saw (in this case a Stihl 024), viewed from the flywheel side (see tapered crankshaft with keyway). Oil tank is on left, piston is on top (cylinder is removed). |
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The same 024 from clutch side, bar studs on right. This saw is old and in poor condition, but quite repairable with non-genuine parts. Worst damage is corrosion around clutch, perhaps from corrosive palm tree sawdust. |
The newer “consumer” design of Stihl has a plastic body that wraps around a more self-contained metal engine. The cylinder and the top half of the crankcase are a single metal barrel, and a metal pan is bolted on the bottom to close the crankcase. Removal or replacement of the cylinder involves a major dismantling of the saw, to extract the motor from within the plastic body.
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This is the type of engine in "consumer" saws, which is bolted into a plastic body (I think this is for a Stihl 029) |
The 2 different types of Stihl chainsaw can be generally identified by their model numbers, using a sort of Stihl numerology. In the old model numbers starting with a zero (mostly from the 1990s, when the modern designs started), the even numbers (e.g. 026, 036, 046) were the professional saws. The later odd numbered models (e.g. 017, 025, 039) were the plastic bodied consumer saws. With the new model numbers starting with “MS” (when for example the 026 was renamed the MS260), most of the professional saws now have an even number as the middle digit (e.g. MS381, MS461) and the consumer saws have an odd digit in the middle (e.g. MS170, MS250). This is not quite a perfect system, e.g. MS180 is a consumer saw.
For me, wanting a saw with an engine about 60cc, there are 3 Stihl options: the old 036 (MS360) professional saw (no longer sold new, but available second hand or as a non-genuine kit), the MS361 which is a more modern and complex professional saw, or the MS391 which is the similar-sized consumer saw. My preference was for the MS360 as it is a simpler design than the MS361, and more durable and repairable than the MS391.
Huztl sell smaller saw kits than the MS360: the MS250 and the MS180. These are both plastic bodied, non-professional saws. They're not bad saws: they're light to carry around and can be repaired with Huztl parts, but they won't be as durable or repairable as the professional saws. My sister-in-law does many hours of forest thinning with an MS180, because it is so light to carry and is strong enough for small saplings.
Huztl non-genuine kits
Through watching youtube videos about chainsaw repair, I discovered the recently emerged option of buying a kit of “Complete repair parts”: a full set of non-genuine chainsaw parts, which can be built into a working chainsaw. The principle source of these kits is www.huztl.net (a name appparently made from “Husqvarna” and “Stihl”), who sell a huge range of non-genuine parts, mostly branded as “Farmertec”.
For anyone repairing their own chainsaws (or brushcutters etc.), the Huztl web shop is astonishing in its scope and its prices. The accessibility alone is revolutionary: Genuine Stihl parts are difficult to find without walking into a Stihl dealer’s shop – you can’t browse or price parts online. The Huztl site has huge catalogues of parts listed with photos, viewable by chainsaw model.
The quality of parts sold by Huztl will take some time to discover. Some parts are clearly fine because they work from new, e.g. clutch covers, carburettors, bolts. Some will be quick to evaluate: chains, bars. Some, however, will take some time to be confident in: pistons, cylinders, crankshafts, bearings, seals. If the quality of Huztl parts is good enough (and I am so far happy), it offers a great resource to backyard chainsaw mechanics. The question of quality and durability is fundamental to my writing this entry, so I will try to report as well as I can on my experiences over time.
Ordering the MS360 kit
The Huztl MS360 kit is astonishingly cheap: mine cost about AU$300 delivered, plus bar and chain for another ~$25 (a new Stihl MS361 is listed at about AU$1600). I made the mistake of ordering parts for other chainsaws, along with the 036 kit, which meant we had some troubles working out what was what – most parts are not labelled.
I ordered a couple T-handled T27 torx tools with my kit. This is the main tool needed for tightening bolts (brilliantly, Stihl saws are almost entirely held together with torx T27 bolts and screws). I also bought a Huztl crankcase splitter tool, in case we made a mistake and needed to open the crankcase. I bought a flywheel puller (2 in 1) tool, to make it easier to remove the flywheel in case of crankshaft seal trouble.
I also ordered some extra gaskets for the crankcase and cylinder, and some spare crankshaft seals. These seemed at significant risk of damage during assembly - we did need to replace one crankshaft seal we damaged while assembling the crankcase.
Assembling the MS360 kit
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Unboxing the parts on the kitchen table |
Nearly all the assembly was done by our son Jasper, who couldn’t keep his hands off the kit. There are no instructions at all, and almost no labels on the parts. Luckily our neighbour and friend had a Stihl 036 we could borrow to look at and to exchange parts. Most importantly there is a rich resource of youtube videos specifically on how to assemble these kits.
Here are the videos we found most useful:
Afleetcommand’s 036 assembly series
Part 1:
Part 2:
Matthew Olson’s “bolt by bolt” 036 assembly series:
There were some other youtube videos on assembling the crankcase which were helpful, mostly found by searching for Huztl. As, well, I liked Andy Reynolds’ chainsaw repair series on youtube, which share some of his accumulated experience with chainsaw maintenance.
For most of these saw kits, construction begins with assembling the crankcase. For us, this was the only difficult bit. We used our wood-burning cooking stove to heat the 2 shells, and used a wooden mallet from our woodwork shop to make adjustments. We damaged a crankcase seal on the clutch side, but it wasn’t difficult to replace (for crankcase seal replacement see https://www.youtube.com/watch?v=znC1HfkCzC8&t=8s). With heat, patience, and a wooden mallet, it isn’t too hard. Oil the shaft to make it easier to slide into the bearings and less likely to damage the oil seals.
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036 coming together on the kitchen table |
Once the crankcase is assembled, it’s just a matter of bolting everything else together.
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The Huztl 036 - without an 036 label on the flywheel cover - otherwise looks just like any other 036 |
Carby troubles
Once assembled, I filled the fuel and oil, and adjusted the carby jet screws to 1 turn from closed (the standard startup setting). I was able to start the saw and run it at high revs, but I couldn’t get it to idle. There was clearly a problem with low speed mixture: adjusting the low-speed jet seemed to make no difference. After doing a crankcase pressure/vacuum test to see if we had damaged a gasket or crankshaft seal, I tried swapping carbies with our neighbour’s genuine Stihl 036. With a genuine carby the saw worked perfectly.
Huztl promptly sent a replacement carby once I sent photos of the non-working part. The new carby worked perfectly.
During the first few hours of use, I found the idle speed variable. Tilting the saw on its side would drop the idle speed and sometimes stall it. Again I worried about crankcase vacuum leaks (I’ve had some bad experiences…). I then realised that the idle speed ajustment screw wasn’t changing the idle speed. Looking closely, I could see that the throttle connection wire (from the plastic throttle finger lever to the carby) was a fraction too long, so the throttle butterfly lever wasn’t sitting on the idle ajustment screw. After I removed, slightly bent and re-installed the wire, idle speed was fully adjustable.
Bar and chain
I wanted to try the Holzfforma bars available from Huztl, but wanted a shorter bar than they supply: the shortest 3/8" bar they offer is 18". So I tried something I'd been wondering about for a long time: cutting a bar down to a shorter length. I did, and it has been quite successful, see my blog post about this at http://bruceteakle.blogspot.com.au/2017/08/shortening-chainsaw-bar.html .
The Huztl chains seem to be good. I was worried about them being soft and blunting quickly: they seem softish to file, but in use we have found them fine so far. Again, their cost is so low it is worth it to do a little more sharpening - but I can't say I've found they blunten noticeably more quickly. I've had to buy longer chain loops and shorten them for some bars, as they only come in particular lengths. I've written more detail on Huztl chains in my review here. [I have stopped using Huztl chains since they switched to chisel tooth]
Using the low cost Huztl bars and chains has given me confidence to try using waste deep frying canola oil (from a neighbour's cafe) as bar oil. I've written a more extensive review of using used vegetable oil in chainsaws on another post. This has worked fine, and doesn't appear to have led to a higher rate of wear. Again, even if the bar did wear a little faster, another $10 or $15 bar from Huztl is fine if it's saved me $100s in bar oil (and I've already saved a few 20 litre drums of expensive bar oil). Importantly, the vegetable bar oil means I'm more confident in using my sawdust for composting and garden mulch.
Decompression valve
After the saw had done a few hours work, one day the plastic head from the decompression valve fell off. This was easy to repair: I peened the head of the valve stem a little so that it had a bit of a burr all around, so it couldn't slip down thru the valve body into the cylinder. Then I pushed the plastic head back on with some epoxy glue.
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The same thing happened to the decompression valve on my Huztl MS660. Here's the cap that just fell off while sawing. |
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Here's the Huztl decompression valve removed, showing the lid off the valve stem |
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I peened the top of the decompression valve stem with a hammer - you can see the mushrooming if you look closely on the left-hand end |
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The peened end is only slightly wider than the stem, but too wide to fit thru the valve body - so it's safe for the engine. After this, I warmed up the plastic head and tapped it back on (this time with no glue). It so far seems fine. |
Since then, every Huztl/Farmertec saw I've made has lost the head off its decompression valve within a short time of starting work. On each saw, I've peened the top end of the valve stem, warmed up the plastic head and tapped/pushed the head back on, without any further trouble.
The valve stem can fall into the cylinder after losing its head. This happened to a friend with a saw we built in our kitchen.
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On this saw the decompression valve stem fell into the cylinder after losing its plastic head. The stem got bent somehow in the process, but didn't cause damage to the cylinder or piston. |
This isn't a good thing to do: just pulling the engine over with the decompression valve stem rattling inside could do serious damage, getting in the squish space or falling part way through a port while being pulled over. If this happens, it should be pretty easy to get it out: remove the muffler, turn the engine over until the piston is at the bottom, and shake the piece out through the exhaust port.
Flywheel key shearing
It's important to tighten the flywheel nut adequately, and to assemble a clean flywheel onto a clean shaft taper, to avoid shearing the key. This wasn't a problem on my Huztl MS360 but my (later built) Huztl 066/MS660 did break down this way.
The 660 had been working fine after being built, but one day it wouldn't run properly. It would start, with difficulty, but ran poorly: it was smokey, wouldn't run up to speed, and wouldn't idle. It seemed like it was running rich, so after checking the mixture screws I took the carby off (twice!) and checked the float needle (if it's being kept open by some dirt it can cause flooding). When the carby didn't help, I thought of timing, then removed the flywheel and found the sheared key.
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Here's the crankshaft taper that holds the flywheel. The piece of key is still in the slot. I carefully picked out the piece of key so I could use it as a model for making the new one. |
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Here's the tapered hole in the flywheel, with a piece of sheared key still in the slot. |
I made a new key from mild steel (the key should be softer than the crankshaft) to copy the sheared one. I forged a small piece of flat bar down to 9mm x 2mm section, then ground and filed the bar end into the right arc before hacksawing off 4mm from the end.
I think the key sheared because I made 2 mistakes:
I tightened the flywheel nut with an impact driver (an impact driver is a very quick and easy way to remove the flywheel nut or the clutch body), instead of taking the time to do the proper bush mechanic's method: lock the crankshaft by taking out the spark plug and pushing in a length of soft cord (like rewind starter cord), then tightening the nut with a socket. It would have been even better to use a torque wrench (I should get one).
Also when I took the flywheel off the shaft, I found the tapered crankshaft end and the inside of the flywheel were greasy. I like to grease things as I assemble, but in this situation it would cause the flywheel to float on grease instead of bedding down tight. Then I read the workshop manual to find it advises cleaning the shaft and flywheel hole with degreaser before assembling (if all else fails, read the instructions…).
Piston pin clips
There is a lot of discussion online about problems with Huztl/Farmertec piston pin clips, and I eventually became convinced this could become a problem for me. I was particularly influenced by posts on the facebook Huztl Farmertec Chainsaw Builders group, about saws that worked fine for hundreds of hours, then had piston and cylinder damage from the piston pin clips fully or partly coming out of place.
Piston pin clips are circular spring wire clips that hold the piston pin in the piston. They spring into grooves inside each end of the piston pin hole. The pins are made of round wire, and the groove is semi-circular in section, so the clips can't be replaced with a normal internal circlip.
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Here's a piston, showing the piston pin in its centre. You can also see the piston pin clip if you know what to look for, with the tail curling into the centre. |
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Here's a Farmertec piston pin clip as supplied, with a long tail curling into the centre |
The problem seems to be that the Farmertec clips have a long tail in their centre. This is very helpful for installing and removing the clips, but it seems these tails can break off after some time in use. Especially if the tail is horizontal, the tail can wiggle back and forth under the inertia caused by the piston's movement up and down - more than 150 times up and down per second at higher speeds. This waggling can cause fatigue and the tail can break off, and jam between the piston and the cylinder - you can imagine that's not good.
Two main solutions are discussed to avoid clip problems: buying genuine Stihl clips, or cutting off the tails.
Genuine Stihl clips have no tail at all: just a circular spring steel clip with a gap. I was quoted AU$2.75 each at my local Chainsaw shop. I'd have to pay up front in store, then wait a week or so, so I progressed without them.
My main youtube chainsaw builder, Afleetcommand, seems to be happy with using the Farmertec clips, but he cuts off the tails, and he has built heaps of chainsaws that have heaps of hours on them. So I decided I'd follow his lead.
I opened up all 3 of my home-assembled Huztl chainsaws, and fixed their piston pin clips. On each saw I removed the cylinder, took out the piston clips, cut off the tails with an abrasive cutting disc, and replaced the original clips back into the piston. I put the gap in the clip facing either up or down, to minimise the forces from accelerating up and down with the piston.
Using the Huztl MS360
Once carby problems were sorted, the Huztl MS360 worked like a brand new Stihl. Compared to other cheap chainsaws, it has the advantage of Stihl’s excellent design. The MS360 is a really good saw for my work, lighter than the Stihl 038 and MS381 that we have used a lot over the last 20 years, but still powerful and having the 3/8 pitch chain advantages.
Once the saw was working, I attached a cheap digital hour meter. This adds up the run time, so I can add up the short runs that are usual for chainsaws.
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Here's the digital hour meter on the cylinder cover. A wire from the meter wraps around the spark plug lead |
So far it’s done 19 hours, which is actually a lot of chainsawing: several days in the forest. It’s been a mix of long, light work thinning cypress (soft wood, small diameters) and hard, continuous, full throttle cutting dead stringybarks into firewood blocks. Nothing has broken or failed, and I’m very happy with the saw.
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The 036 working in the cypress thickets |
Is the Huztl MS360 any good?
So far, I’m very happy with the Huztl MS360 It’s fair to say it’s seriously changed my understanding of chainsaws.
The first advantage is that we needed to put it together. My son and I learnt a lot from making it: once you put a machine together like that, it is never a complete mystery again. We know every part, and feel confident that we can deal with mechanical problems.
Easy, low cost access to a complete range of parts for these kit chainsaws, that appear to be of good-enough quality, is also pretty revolutionary for chainsaw users like me. It stops chainsaws being throw-away consumer goods when there is a breakage or failure – not necessarily because genuine parts aren’t available, but the cost of genuine parts and dealer labour is often too big a risk for an old saw which might have other problems. If a saw you made yourself wears out a piston and cylinder, and the parts cost AU$30 to replace and you have confidence to do it yourself; then that saw is likely to be repaired and work on.
Remember that the low money cost of these parts is balanced by the need to be your own mechanic and do some quality control for yourself. It’s very different from stopping off at the Stihl dealer and picking up a new saw that is immediately ready for work. If you do buy these parts, be ready to take the time to check the parts, put things together carefully and if needed, to ask for replacements.
Breakdowns
One of the MS360 kits made on our kitchen table had a major engine breakdown after a few dozen hours use. Somehow the big end bearing (between the con rod and the crank) rollers fell out, leaving the con rod bore hammering on the crank pin until it wouldn't go any more. The rollers rattling around in the cylinder wrecked the piston and cylinder, then seem to have been spat out of the muffler - I couldn't find any rollers at all. I replaced crankshaft, piston and cylinder, and the saw is working fine again now.
I put this failure down to some quality control problem with the big end bearing.
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Here's the piston, with its crown bashed up by fallen-out rollers |
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The top of the cylinder also got a hammering |
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I pressed the crankshaft apart in a bench vise (surprisingly easily) to show the parts. Front left is the roller bearing cage, missing all its rollers and hammered between the con rod and crank pin. Front right is the con rod, with a big burr on the upper side of the crank pin bore, from running for a little while with no rollers. The crank shaft itself is fine. |