Talltone

I have identified that the electronic ignition (no points) on my 028AV chainsaw is not producing a spark at all. The plug is new and properly gapped, the flywheel magnets are at the correct separation from the coil and the connections are checked, clean and correct. As replacement coils seem to be rarer than hens teeth, what are my options for repair? I am aware that I could use the older points flywheel plus electronic gismo, but in the first instance would like to repair or replace the existing system. Re repair option, is it possible to replace the main HT lead into the coil - it does not look like it just plugs in like old fashioned auto leads. I did try pushing a pin in to the HT lead a few mm down the wire but this also failed to produce a spark. Grateful for any help.

Thanks a lot for very quick comments and useful graphics etc. However, I ca't see how to move along as my problem persists: 1. Despite a VERY CAREFUL strip down, clean and re gasket/diaphragm of existing carb (plus replacement of fuel, fuel filter and impulse lines with new OE parts). 2. Despite substitution with another pre working carb. 3. Despite adjusting rotor/magnet gap and testing to establish that spark is OK. From this logic I can only surmise that fault lies in the fuel delivery to carb, which in turn implicates the impulse line. If, as it appears from the videos, that there is NO valve in the primary engine system (as opposed to valving present in the carb secondary system) is it a possibility that the impulse line is blocked or restricted somehow? Getting desperate now, have five multi stumps, an oak and holly tree to remove prior to spring! If you can hear a high pitched Heeeeeeeeellllllllllpppp in the distance - that's me!!! So grateful for ANY further wisdom.

Hello, calling all Arbs again! Cold weather and vacations have interrupted recent work on my Stihl 028 but have the following progress to report BUT chainsaw still not working properly. 1. Adjusted the flywheel to coil gap with A4 paper as recco'd. 2. Checked spark with an old plug with electrode bent to 45 deg as recco'd. Not a fat, blue spark but still jumping the gap OK. NB:This was done with cordless drill and socket on flywheel nut giving saw a good turnover. 3. Fitted replacement secondhand carb. Saw started and ran for a minute or two, more or less normally, then died and would not re-start despite many attempts. I'm inclined to think now that it is only a carburation or rather a fuel problem. So, as the symptom persists, despite two carbs being used, it implies that the impulse line is not functioning properly despite new tube being fitted. Assume saw started initially because of fuel provided by many revs using cordless drill. So again, need to know how impulse is provided to carb and whether there is a valve system to clean and what access is required? Are there any tests to assess if actually working properly? Any help very gratefully received.

Thanks for all advice given. Not sure I can use the electronic gismo as this model has electronic ignition anyway - no contact breakers etc but will try to reduce the magnet to ignition module gap as recommended. Will try the extended gap diagnostic too and examine the spark energy. Have just purchased a s/h carb so hope that might give me another steer too. Will let you know what gives.........

Thanks for advice given. Had changed the impulse hose as part of carb strip down ( was hoping it was the original fault source but no luck there). Carb also checked and checked again against assembly instructions so should be OK. Compression is really good though accept need to do a proper check. Air leak possibility is interesting and will be investigated but as said all parts reassembled carefully. Out of interest, carb kit was supplied with carb to manifold gasket where none was fitted previously. Comments online suggest that rubber manifold tube fulfills that role and no gasket was fitted originally - any comments? Again, would like access to a service manual for the 028, any pointers to where I might find, have tried online without success.

Hello all, my first post on Arbtalk so hope you can help please. Have used my 028AV over about 10 years for domestic tree felling and woodcutting. Suddenly, recently experienced the saw cutting out after a short time but would then re-start and cut out again moments later. In the end, suspected carb probs and cleaned / rebuilt it using new parts including new fuel line/filter and impellor. Also cleaned out exhaust box (needed it!). Saw was then very hard to start and when it did ran at v high revs before cutting out again. Turned attention to electrics - change of plug, clean /adjust position of electronic ignition (credit card trick? - no, used feeler gauge). Spark seemed weak but was present. Now can't start at all - very frustrating. Compression seems very good and is expected as saw has had only light domestic use. Any clues please on where to focus my attentions? I'm an engineer so am very careful about what I do and repair loads of stuff but this has stumped me. Be ideal to swap either the carb or electronic ignition to help diagnostics. Carbs are on ebay for just £16 via Hong Kong - are they any good? Anyone have a service manual? Grateful for any help, saw is too good to abandon.