OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Chainsaws and Concrete Cutters Petrol Chainsaws and Concrete Cutters Ozito chain saw

A bloke dropped off this saw last week with the pull starter gear stripped (it has 4 teeth on a plastic wheel) I started it with a drill to prove it will run, then I repaired the teeth ( still waiting to hear back from Bunnings to see if a new starter is available, not holding my breath) Anyway I fitted the repaired starter but on trying to start it the compression is way too high and this is why the starter was stripped( funny how you never get told this, "oh the starter is broken can you fix it") Is there any type of decomp valve on these things that anybody knows of? it spins over fine with the plug out so the repaired pull start is not the problem

No decompression valve that I know of. Is it one of the little 12 inch 25 cc arborist saws (really light that you can carry up a tree) or one of the bigger 41cc 16 inch bar ones?

The little arborist ones aren't difficult to pull start, but they do feel a bit harder than an equivalent sized line trimmer - but a bit easier than a trimmer without a clutch. They must be high comp to wring more power out of the little engine.

Hi Tyler it is a 16 inch one, starts easily enough with the drill

I have heard those ones (haven't had anything to do with repairing them directly) will strip the starter if the person doesn't follow the 'pull slowly until resistance is felt' clause in the manual.

The Baumr-Ag, Giantz and similar ebay brands do the exact same thing.

It should be common sense to treat all pull starters that way. Be ginger and feel for it to engage before pulling briskly. Pulling hard from the get go is like putting an automatic into drive or reverse while the engine is revving, you just don't do it.
It's amazing how some people treat equipment

Probably stems from them doing standing starts - not putting the saw on the ground.

It also stems from the original selling price - those things went for $150 odd regular, then down to $120 or less sometimes.

The best I have heard is 'It's a Talon - it doesn't require servicing.'

That being said, I have also seen a guy with a stihl, sitting on a tin fence about to take a branch off the tree with the middle of the chain drooped about (no joke) 1 inch from the bottom of the bar.

Norm depending on the size of the drill you used, the recoil assembly itself maybe the problem. I have seen where the starter pulley would bind on the center post due to wear on cheaper recoils here and I have replace several over the years. As for the tooth wear it is normal for them to wear out and isn't cause by the compression load though most of these 42CC class saw run 130-165 psi compression when new. Sometimes the wear is from sticky engagement pawls.

And yes the customers are bad to not tell us about problems hoping we will fix them for free.

It sorta like the Bobcat UTV I just sent out of the shop. It came in with front end bushing and CV boots bad. Engine was barely able to run. The customer said he had checked by the Bobcat dealer and was it was a bad fuel pump. THe frond end repairs was no problem other the few hours it took cutting out the bolts. The fuel pump was rebuilt but it only made the problem worse. The ECM was saying that the TPS was bad so I replaced it, still no change. Found the injector partially clogged so I installed a new one, still no change. By accident I found that the system wasn't charging. What I found as a cause was the stator wires were complete worn though and shorting along the CPS sensor wire rubbed bare. I repaired the damages and believe it or not the problem was corrected. I am thinking the bare CPS wires was causing the problem.

Anyway I now got to buy a new crimper so I can do weathertite and Metripack terminals. Always something isn't it?

AVB, it didn't stop charging the day it came to the shop, I bet he had been charging the battery up at night for months, but it would not occur for him to tell you

Well the current owner only had it less than a month so it couldn't have been for months on his part but the previous owner very well may have. He buys and sells them routinely so I get several different makes and models in during the year for repairs. He actually a former tech but is having to give up on them due to health so he got me to do a lot of the heavy work. Plus working on them get me through the winter months here.

The newer ones are a pain to work on with all the electronics involved with the need of costly specialized electronic test equipment. UTV (side by sides) are easier to access things than the ATVs. Newer ATVs are worst than the new cars when it comes to working on them. Everything is so tightly packed. I rather work on the lawn care equipment.

As I said I got to get the new crimper but it not just for the ATVs and UTVs as I have been running into the weathertite connectors on riders too. I got to learn how to repair these newer wiring harnesses so I don't to replace complete harnesses for a simple broken wire at the connector. Pretty well know what needs to be done just got to have the right tools to do it so I can disassembly the connectors and properly crimp on new terminals. Plus I got to source the parts as the equipment OEMs are not providing them for the mowers or anything else as they prefer to just sell the complete harnesses.

Electronics are even showing up in the more expensive chainsaws now with Stihl's Mtronics and Husqvarna's Auto Tune systems out there. Just wondering how long before someone tries fuel injection again on push mowers. Robin tried it on the small single cylinder engines but fail and they went back carburetors.

I know Briggs is trying fuel injection but that is on their very large twin engines. I just haven't seen one here in the shop yet. Hard to learn something when you don't see it until it is worn out.

Ford, GM and Chrysler used computer controlled carburettors in the 1980s with different sensors. They were called feedback carburettors and were effectively a stopgap for EFI. Maybe this idea will make its way to single piston small engines.

Can't see them going EFI on mowers because the electronic side of it requires a power supply, meaning battery and alternator, that is not impossible but will ad significant cost for little gain and extra weight, so then they would need to be self propelled

Briggs already has electric start engines for walk behinds. Small light weight starter, small stator, and flywheel with a ring gear added to the engine. Don't remember the model off the top of my head right now. Then mower OEM adds a small gel cell battery pack and wiring for a key switch so they are started just like an electric start rider.

Yes the ones I have seen are on SP mowers. Wasn't that hard to push without the SP working. But of course the kids complain even having to walk behind a mower here. So much that one customer got an el cheapo manual reel mower just so his son would appreciate the SP mower.

So going to EFI wouldn't be a problem once they figure how to get it to work properly having it easily serviced, and is durable.

Should be able to incorporate easy starting too. Of course, it will be marketed as a premium feature like in cars 30 years ago before becoming standard.
Might be vital for meeting establishing emission targets.
I'm sure an ECU for a small engine doesn't need that big of a battery anyway and it could be a compact lithium battery the size of a 9 volt battery that gets recharged with each mowing.

This is how Robin had the EX21 EFI engine wired. Didn't even have a battery.

Yes anything can be done but will it make them cheaper, as we all know everything is controlled by the cheapest item. Sure some people will buy a quality product at a premium but the fact China makes million of cheap mowers (and this is the volume market that fall to bits) why try complicating a simple design for the smaller end of the market. The electronic ignition was a major step forward from points ignition and I doubt anybody would have argued against it but going to EFI I think would be an expensive backwards move.
AVB, how did the Robin perform, is it sweeping the market as the next big thing? All those extra components in there instead of a good old simple carby

Actually only the throttle body, power coil (stator), and temp sensor were the only additional parts.

It did performed well when it was working. The problem was that the throttle body assembly wasn't robust enough to handle the day to day operations that careless operator had put the engines through. When anytime the throttle started acting up the only option was replacement. Robin finally just say for all future repairs we were convert the EX21 EFI back over to a carburetor setup.

I still a Robin which Subaru owns and makes the engines but I only see one on UTVs every so often and they are carburetor versions. The last 650 was a pain to start during the winter until I modified the choke vane. Robin/Subaru engines seems to be very good engines in general.

High vibration will certainly kill electronic stuff, apart from the environment mowers operate in

We know all too well that solid state components are far from robust and reliable, contrary to what the name implies.
Electronics, especially poorly made Chinese ones I have encountered, are even more problematic than mechanical things with moving parts.