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About oldnwrinkly

  • Rank
    Junior Member

Personal Information

  • Location
    nr Machynlleth, Wales, UK
  • Occupation
  1. Mysterious problem Stihl 038 AVS

    But have you checked to see if it distorts when the saw is on its side? I am not familiar with the saw so don't know if this is a possibility or not. Are the AV buffers in good condition? Dave.
  2. Mysterious problem Stihl 038 AVS

    Have you checked the impulse hose? Is there any possibility that this could be pinched/flattened or twisted, when the saw is on the side, due to worn/soft AV buffers? Just another long shot but most of the usual things seem to have been covered. Dave.
  3. Tachometer mod

    I don't know if this is of any interest but ................. I have a cheap hand-held optical (non-contact) tachometer which I thought might be modified to work as a induction tacho to use for tuning saws. In it's original state the unit has a low power laser which illuminates a piece of reflective tape that is applied to a shaft or flywheel etc. and a photo-diode which receives the reflected light pulses. My plan was to disable the photo-diode and replace it with a small induction coil which, when held close to the spark plug/HT lead (or the flywheel magnet) would pick up pulses and these would be de-coded by the circuitry to give a read out of RPM. I tested the principle by resting a coil on the engine cover and measuring the output on a DMM set to read frequency. I also compared the accuracy of the readings by fixing a magnet to the chuck on my minilathe, which has a tacho, and after converting the frequency reading to RPM (x60) the readings were identical. So, today I knocked up a rough and ready, very simple circuit, soldered it into the tachometer and tested it against the lathe taco. It matched the readings exactly up to 1,000 RPM - I didn't take it any higher as although I had added a few bands of tape over the magnet, the thought of what could happen should the magnet let go is scary. I am fairly confident that it will be just as linear at higher revs as although the unit is a cheap one the chipset looks reasonable - the microcontroller is an 8051 type (Atmel AT89S52). As soon as I have made a proper job of adding the bits and pieces into the case I will try to test it against a commercially available 'saw' tacho. If anyone is interested the add-on bits are - a small, fine wire, coil wound on a thin ferrite core, a 'snubber' diode wired directly across the coil and a series diode, for polarity purposes, on one end of the coil. The positive lead of the photodiode was snipped and the cathode ( ->l----) side of the series diode connected to the circuit board end of it. A short length of wire was added to the other side of the coil and this was soldered to the negative lead of the photo diode. The polarity of the photo-diode leads are marked on the circuit board. The laser will still light up but this will not matter. I intend to add a switch so the unit can be used in either the optical or induction mode. I bought the tachometer on evilbay for very little money - it is identical to this one < LCD Digital Laser Photo Tachometer Non Contact RPM Tach Last Max Min Value Top | eBay > Dave.
  4. Anyone bought from these people?

    WorcsWuss, Thanks for the link - informative website. Dave.
  5. Anyone bought from these people?

    Came across this site for "Chainsawchains.eu" - Chainsaw (Chain Saw) Chains - Oregon chainsaw stockist - low cost chain saw chains - and as their prices looked good I decided to buy a chain loop to check them out but, when I tried to 'checkout', Firefox came up with a warning ........ "This Connection is Untrusted" etc, etc. So, just wondering if they are kosher or not. Dave.
  6. Pistons - fried like an egg!

    Thanks for the very comprehensive reply, Spud. I have some sheet rubber so will make a 'gasket' for the exhaust and work out something for the inlet port. I also have a gauge and other bits lying around somewhere. I suspect the crankcase seals are a bit iffy as the tick-over is erratic and the saw sometimes surges. The carb boot looks OK - no cracks or splits - and is still a tight fit, Everything else I have checked seems to be in order. Dave.
  7. Pistons - fried like an egg!

    I want to pressure test a Husky 136 so did a search and came across this post. As I have never done this test I wonder if someone could clarify a couple of points please. RE: ".... a fitting that links to the engine that allows the air in ....". How do I get the air in .......... the impulse port maybe? What is the usual method of sealing the exhaust and inlet ports? Also, is it necessary to monitor the induced pressure over a period of time and, if so, what would be a reasonable length of time for the crankcase to maintain a steady pressure? Dave.
  8. Husqvarna 236 - Opinions

    Thanks all for the prompt replies and advice. Problem is I cannot see a 345 or 350 listed on the Husqvarna web site and a quick web search didn't come up with any retailers selling them. The 346 and 550XP are way beyond my budget considering any saw will only be used infrequently and also, as I really am getting to be 'old n wrinkly' (and getting increasing problems with arthritis!), I doubt I will still be sawing in three or four years time. The 236 has a 38cc engine which is the same size I have been using for the past 27 years - although I imagine a modern Husky will have a lot more power per cc than the Solo's thirty year old design - ? I can't say that power has ever been a real problem but I always keep the chain really sharp and the saw tuned well. In fact I would have been quite happy to carry on using the Solo but, unfortunately, spare parts are no longer available so it will have to be retired, hurt. Dave.
  9. Husqvarna 236 - Opinions

    Thinking about getting one so thought I would ask if there are any known issues with this model. It will be used for firewood - we have a small Rayburn and a Villager stove so cut a few tonnes of wood P.A. Used to use an old Solo 606, 38cc with a 12" bar so this looks like a direct 'drop in' replacement. Anything else worth looking at? .... Proviso's - must be light and manoeuvrable as I am usually working on the slopes of our local steep valleys (and ravines) here in Wales and, given that for 6 months of the year it will lay idle, price is also a consideration. I have thought about a SH 136/7 also but therein might lurk gremlins - although I have kept the old Solo going for 27 years and coped with most problems - unless it's a genuine low hours saw.
  10. Fuel supply question - Ryobi RCS 3335

    With the engine cover off you have a good view of the cylinder and easy access for cleaning so I regularly brush and blow out any fine sawdust deposits from the fins and the rest of the cooling air path. As I noted, the mixture appears to be OK (maybe even a little on the rich side ?) so all in all I don't think it's a case of overheating during normal running. The plug colour looks about right - dark tan so not a weak mixture. At the moment I am still convinced that the problem lies in the fuel system - I just cannot understand why the priming system loses pressure when the saw is hot - but, just in case I am wrong I have checked the plug. The gap is spot on (0.025") and there is a good spark when the engine is hot - whether it is still timed correctly may be another story. A spare plug made no difference. The operating instructions do say that the primer should be operated for a hot start and to just omit the choke operation, as you would expect. After fitting the new gasket the carb did need re-tuning - the mixture was a little too rich but after adjustment the saw still would not start when hot. Thanks for all the replies thus far. You might wonder why I am persevering with this thing - you could say that it's earned it's money with two or so years of use and could be binned - but it annoys me when I can't find a reason for what appears to be a simple problem. Apart from that, generally the saw is in very good condition, nearer to just 'run-in' than worn out and, probably because I grew up in a time when stuff like this was expensive and scarce, it seems a waste of resources to throw it away because of a niggley fault - after all, it does start and run well (mostly )
  11. Fuel supply question - Ryobi RCS 3335

    Les, Thanks. Yes, a vapour lock seems to be the problem but I couldn't see a way around it. I assumed that the fuel was vaporising in the carb but, as it is fitted with a bulb primer I thought using this might have forced fuel back into the carb. Obviously the lock is blocking this route also. As supplied, the 3335 did not have a throttle lock but did have a blanking plug over a hole in the handle where one would be and the trigger 'safe' lever also was designed to accommodate a pin/button so I turned one up from SS. I always did a hot start on the Solo with the throttle locked on full. However, even trying to start the 3335 with the throttle locked open doesn't work. All of the other points you mention are within my normal operating procedure/care and maintenance routine ( e.g. I run a 40;1 mix as opposed to the recommended 50:1). I am hoping that fixing the gasket problem I mentioned may help - if the pulse was weakened due to the transfer channel being partially restricted this would result in low efficiency pumping, yes? I forgot to mention that this hot start problem is relatively recent. I didn't notice it when the saw was new.
  12. Fuel supply question - Ryobi RCS 3335

    Thanks for the reply, Gardenkit. Re. the mixture. The 'L' needle is set so the engine is just four stroking a little on tickover. I have tried setting it richer and I have also checked the 'H' setting - this is tuned to max revs and then richened to a slight 'burble' as per usual - but, as I said the saw cuts well (given its puny 33 cc) --- Earlier this week I was logging some fresh felled 25-30" diameter oak and, although slow going, it went fine .... until I switched it off I checked both diaphragms very carefully for punctures and damage and they are both fine. The carb is only a couple of months old (I complained bitterly to Ryobi about the lack of a carb repair kit - there isn't one yet for this saw - and they sent me a new carb !!) so the diaphragms should be good. The carb is mounted to the cylinder via a typical plastic spacer which transferes the engine pulses from the bottom of the engine manifold to the top of the carb. The plastic looks to be of reasonable quality and does not show any deformation. I removed the carb again last night and did notice that the (very low quality) gasket between the carb and spacer was deforming and had reduced the depth of the pulse transfer channel quite a bit so I have made a new one. I will re-assemble it all later today and check it out - probably will need to re-tune the carb settings. This is the first time I have encountered a bulb primer system but it looks simple and straightforward and that's why I am puzzled at the way the saw is behaving.
  13. Fuel supply question - Ryobi RCS 3335

    I know - bin it ........... but it's only got about 20 hours on it although it's now out of warranty. It cost me £40, brand new + warranty (long story) and I bought it as a replacement for my 27 year old Solo 606 firewood saw. After some initial carb tuning it has always started and run well from cold (still does) but, when hot, if switched off and left for 10-15 minutes it will not start. The problem seems to be fuel. It has a primer bulb and, when cold, after a couple of pushes the bulb fills and you can feel pressure. When it's hot the bulb goes in and out without any pressure and only ever has a small amount of fuel in it (lots of bubbles). Left to cool down for 45 minutes the primer has pressure and saw starts fine and if not switched off will run out a tank of fuel without any problems. I have stripped and cleaned the carb and all of the filters are clean - ditto the tank vent. The fuel lines are still flexible and make a tight seal on the carb. I'm stumped. Anyone come across this kind of thing and found a fix? I know it's only a 'toy' saw but as I said, it starts, runs and cuts well if not pushed too hard and fills my need - also at 68 I don't think I will still be sawing in a couple of years time so if it lasts that long ...............


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