Category: Miscellaneous

This is an inspection report of my 35 year old Stihl BG85 leaf blower.

The blower suffered two faults in its first 18 months:

• the black fuel hose rotted, unsuitable materials given that the only fuel available here was E10 at that time; and
• the on/off switch became intermittent sometimes not stopping the engine unless it was operated 10 or more times.

The same two faults occurred in a Stihl line trimmer purchased at the same time, neither were covered by warranty. Since the underlying problem was unsuitable materials and clearly an unreliable batch of switches, and Stihl’s citation of their 12 month warranty terms to escape the cost of repair… I have never bought another Stihl tool, and probably never will.

I baulked at paying Stihl for replacement switches (partly out of concern the new ones might be no better than the failed ones… same source that obviously has a quality control problem), the switches were replaced with compatible ones from China, ~$8 for 10, no faults in the first two selected after 35 years of service.

The spark arrestor clogged up by about 2000 (as they do), and broke out of the muffler when I tried to remove it. Wow, a replacement muffler was almost $200… treat them carefully. I cleaned the spark arrestor and brazed the whole assembly back into the muffler. Next time I will clean it from the outside with a narrow oxy acetylene flame and compressed air.

This thing was run on E10 unleaded from new until about 2009, it was all that was available thanks to Greenies. Stihl oil (bundled with the purchase 50:1 was used until about 2015 when I switched to Amsoil Saber (again 50:1.) Continue reading Stihl BG85 leaf blower inspection report

The article describes a simple but handy utility menu for a RPi installation of radiosonde-auto-rx.

This utility uses a text mode terminal, so access by a SSH terminal session or a terminal windows if running under a GUI.

Above is a screenshot using Putty. The menu contains most things I need to do from time to time in monitoring / configuring / upgrading radiosonde-auto-rx. Continue reading A handy utility shell menu for radiosonde-auto-rx

I use some Dial Test Indicator (DTI) magnetic stands purchased at low cost on Aliexpress. There are two types.

Above is the small type with a rather simple clamp for the DTI.

Above is the larger type which has an DTI clamp that allows small adjustment of the dial reading (the adjusting knob is hidden here.) Continue reading DTI stand modification

The Toro MX4250 is a ZT ride on mower (riding mower).

A recent inspection at 220h revealed that rear tyre wear is uneven (as would be expected for this type of application), tread depth inside to outside was 1.5/2.5mm and 1.8/2.6mm.

To wring a little more life out of the tyres, they were reversed on the rims, and rotated left to right.

Small diameter wheels, especially wide ones can be difficult (these are 18×7.50-8 tyres), but these were much easier than the front castors which needed tubes inserted when the mower was quite new.

Above, a Bead Cheata was used to break the bead. On one side of the wheel, the bead needs to be forced down more than 50mm, the other side is easier. Beyond that, tyre levers were sufficient. I used a little mounting lube on the beads to remount the tyres, that makes the job a lot easier. The tubeless tyres reseated for inflation pretty easily, a few bounces of the wheel and they inflated just fine. Continue reading Toro MX4250 rear tyre mid life maintenance

Rob Clark from Mansfield in a video by Tim Thomson demonstrated a strainer knot for fence wire. Rob called it his “Everyday Knot”, Tim thought it needed a name and named it the “Mansfield Knot.”

Strainer knots are ones that go min line and must be tied between two strained end ends in a wire span, without releasing much tension from the span when the strainer is removed.

Above is a pic from instructions supplied with a Donald Wire Strainer, a quite old device that I am not sure is still available. The Donald Wire Strainer was my first strainer around 1970. Let’s call the left hand part the standing part and the right hand part the running part. Note that after pulling the running part through the U loop formed near the strainer grip, the running part is wrapped firstly over the standing part. Continue reading The Mansfield strainer knot for fence wire

The Toro MX4250 is a ZT ride on mower (riding mower).

During recent spindle maintenance, I noted that the idler bearings were quite rough. This was surprising as they had only 30h or service over 15mths.

Above is the clone 106-2175 idler assembly, right hand is top side. Note the bearing seal is at the bottom of a cup about 3mm deep, a cup that can retain water (the fixing bolt effectively closes off the centre hole).

Above is a pic of the top side of the idler bearing with the seals removed. Not the corrosion on the rebate in the inner ring where the seal runs. Corrosion has allowed water pooling in the idler assembly to enter the bearing. Continue reading Toro MX4250 deck idler maintenance

The Toro MX4250 is a ZT ride on mower (riding mower).

I previously reported that after 200h, the original spindle bearings were in very poor condition, about 3mm of play at the blade ends, and they were replaced. There are lots of Chinese parts on this “made in the US made” mower, so the bearings might well have been Chinese in origin.

The original spindles are not greaseable, and were fitted with 6203RS (rubber seals on both sides) ball bearings.

There is lots of stuff online about mower spindles, they are a significant maintenance problem.

A grab bag of online expert advice:

• No need for greasing, the bearings are sealed for life (that might be less than 100h).
• Modify residential spindles by adding a grease nipple like commercial mowers use.
• RS bearings cannot be greased, the seal will pop out.
• Punch the bearings out, remove the inner seals and put them back.
• Fit a grease nipple and remove the rubber seal from the inside of both bearings.
• Some commercial mowers are fitted with a grease nipple and metal shielded (ZZ) bearings.

Since these spindles hold a lot of grease, I intend greasing with a pneumatic greaser, and they tend to inject very quickly and the risk of an RS seal popping should be mitigated.

Above is a 6203ZZ (metal shielded) bearing. There is a gap of about 0.5+mm between bearing inner ring and the shield, shields are on both sides. I note lots of online discussions that incorrectly refer to *RS bearings as shielded. Continue reading Toro MX4250 spindle maintenance

SiK is an inexpensive data radio commonly used by UAVs.

At least two of the ‘ground station’ applications incorporate facility for firmware upgrade, but if you aren’t using them for their main purpose, it is a huge installation just to upgrade the SiK radio.

Above is an inexpensive C2 programmer with DIY pogo pin adapter, one of may options. A C2 programmer is needed to write the bootloader.

The SiK radio project publishes a python script at https://github.com/ArduPilot/SiK/blob/master/Firmware/tools/uploader.py . This article gives a revised version that works on a HM-TRP radio under Windows 11.

The firmware was v2.2 sourced from https://firmware.ardupilot.org/SiK/stable/ .

Here is the revised Python script: Continue reading Stand alone update of SiK radio firmware

I purchased a Holzforma G395XP chainsaw, it is a Chinese clone of the now discontinued Husqvarna 395XP It is a relatively old technology carburetted engine without stratified intake and without introducing electronic auto tune, a 30 year old design.

Some of the fasteners used to hold the top cowl down were noodled and would only work with a plain slotted screwdriver. They were replaced with hex button head screws.

In the light of experience with Holzforma / Farmertec G372XT chainsaw – early evaluation, a decision was made to preemptively vacuum and pressure test the G395XP saw.

It failed the vacuum test, not really badly, bad badly enough to warrant repair. Continue reading Holzforma / Farmertec G395XP chainsaw – first impressions

I have a Toro ride on mower (riding mower in North America) which I ran out of fuel when it was quite new (<1y) and having put 5l of fuel in the tank, it would not start after quite a bit of cranking.

In this instance, the battery failed. Prolonged cranking can buckle battery plates, or open intercell connecting links, and although this was prolonged cranking, it was not ridiculously long. Perhaps the battery was the real cause of the failure?

Nevertheless, I asked what I could do to prevent this recurring. Continue reading Toro ride-on mower fuel system blues