Howard 350 (Kohler engine) restart after years.

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  • #39476
    rjy
    Participant

    I’ve got a 350, which I used to use maybe 25 years ago. It looks in reasaonable condition, having been stored dry indoors.

    I would like to use it again! Is there anything I should watch out for, or do, before trying it? Seals? Bearings? Yes, new oil, adjust the weedcutter blades, clean out the carb, fill the air filter… what about petrol? Unleaded?

    Any help much appreciated. I remember hot days in the sun, tilling away. Looks as if I could be on for some more! Fingers crossed!

    • This topic was modified 1 year, 10 months ago by rjy.
    #39478
    enginear
    Participant

    I used one a few months ago that had not been started for at least 5yrs , tank was cleaned, oil changed, new plug and it run on E10 no problem, drain tank after finishing this year and run engine until carb is empty and you should have no problem.

    #39480
    wristpin
    Participant

    Always a good idea when an engine has been standing and before you try to turn it over, to remove the plug and squirt in a good dose of lubricant, wait a while, then gently turn it a few degrees back and forth. If it moves feely, go for a gentle rotation, then refit the plug and proceed as normal. A good precaution against ring damage etc if a bit of rust has formed in the bore.
    ,

    #39926
    rjy
    Participant

    Thanks. I have had a go with this. Afrer draining the sludge in the engine and gearbox, I refilled with straight SAE30 (from Toolstation) and SAE90 (Eurocarparts), and after pulling it over for a while (plug out) started it. Good! E10 petrol, as recommended and further looking says is OK.

    So, I ran it up and down a piece of ground. A bit smoky. After 50 yards it stopped. Would not restart. No spark.

    Investigated, looked online to find where points are (boxy cover, under exhaust, on back of engine). Mystified. No connection to anything! Wire cut off, seemingly a long time ago. Removed flywheel[1], possibility of bad connetion (wire nut) on LT side, soldered, looked further, cannot fathom how this works at all, let alone sometimes. There is a wire running from the LT to earth, another to a small electrical thing with “KB03” written on it bolted to the back (outside) of the cover plate that the coil is attached to which has 2 wires, one from the LT side of the coil, the other to earth. I have no idea what this does. Anyway, I bought it a new sparking plug (NGK B6S, Motor Parts Direct), put it all together again (using a piece of plastic to hold the coil core off the magneto flywheel while the bolts were done up, not sure if this is correct procedure), gapped the plug to 25 thou, and off it went.

    Again – did about 50 yards, maybe more this time, a bit smoky, cut out, seeming no spark!

    What could it be ? What’s going on with the “no points” ignition system? How the blazes does that work?

    [1] Oh woe, woe and thrice woe! Someone has forced a nut onto the end of the crankshaft that does not fit. The threads are ruined, all sharp, distorted, flaky. I did it up again very carefully and not as tight as I would have liked. What can be done with this? I had a desperate thought of filing off the threads, using the root of the thread as a guide, and cutting (say) an M12 thread (coarse or fine?) on the end of the crank. Any other ideas?

    • This reply was modified 1 year, 8 months ago by rjy.
    • This reply was modified 1 year, 8 months ago by rjy.
    • This reply was modified 1 year, 8 months ago by rjy.
    • This reply was modified 1 year, 8 months ago by rjy.
    #39931
    charlie
    Keymaster

    Photograph of what you have in the magneto would help but it sounds like and electronic ignition device has been fitted to replace points.
    Damaged thread is a bigger problem and will probably need a new crankshaft, again a photograph would help.

    #39932
    rjy
    Participant

    Hi, Charlie, thanks for your reply.

    I’m rather reluctant to take the thing apart again unless vital, the threads are bad bad bad, as I’d like the machine to do one job in the next couple of weeks before dealing with it.

    Anyway.

    There are no connections *at all* to the points, only a wire cut off at the exit through the grommet of the cover.

    There is a thing that looks a bit like the attached (from “my old machine”) bolted to the aluminium casting that fits behing the cast iron flywheel-blower-fan. Yes, I think it has got electronic ignition. This device has a vertical pattern on it, unlike the chevrons of the attached picture, but is otherwise similar.

    The black plastic encapsulated coil under the flywheel is mounted on a laminated “C” shaped metal core. There is a steel screw through the core (that does not screw into anything else) that seems to allow for dismantling the core itself. The core is bolted to the engine with two bolts. There is a magnetic rotor on the crankshaft to generate current when the engine turns.

    The HT wire just pushes into the coil, a short length of copper inner being bent back up the outside of the wire to contact the inside of the hole it pushes into in the core. The HT wire goes out through a hole above the coil, and up the back of the engine to the sparking-plug.

    One LT connection from the coil is earthed. The other LT connection from the coil is soldered (replacing the wire nut join) to a wire that follows alongside the HT lead out through the hole above the coil; this LT goes to one connection leg of the “thing” in the attached photo. The “thing’s” other connection goes to earth.

    I’m at a loss to know how it works, but when it’s actually running, it’s fine. Then it just stops, seemingly with no spark, or possibly – hard to see – an intermittent weak spark.

    There are no other cables or connections involved. No capacitor. Nothing.

    • This reply was modified 1 year, 8 months ago by rjy.
    Attachments:
    #39935
    wristpin
    Participant

    Stay away from E10 for as long as you can – stick with E5 or even ethanol free if you can get it.
    The ignition trigger unit that you illustrate is what is often marketed in the UK as a Nova, and it’s fine for your Kohler. I happen to prefer the Meco as it’s smaller and easier to hide within a flywheel magneto.
    Assuming that your Kohler’s coil has two small diameter wires in addition to the HT lead, one will usually be the low tension lead that normally runs across the back of the engine to the points and the other may be an earth/ground. If it only has one small diameter wire, it is the low tension wire which should be attached to one terminal of the trigger unit. I don’t think that it is polarity sensitive, so its other terminal is grounded. If it doesn’t work, swap them over. I have, in the past, found that the insulation on the low tension wire cracked, and shorted out where it runs across the back of the block under its securing clip.
    The trigger unit replaces both the points and the condenser, so there should be just one low tension wire from the coil to the unit – unless there is also a handle-bar mounted kill switch, which will have a connection to the low tension / module wire and a ground. If your machine has a kill switch, I would check all its wiring for shorts to ground / earth – or disconnect it – remembering that you will need to short the plug out to stop it!!
    As far as your chewed up crank thread goes, I would be inclined to cut off the offending bit, counter drill and thread it to take as big a set screw as the diameter of the crank will safely accommodate. Coarse thread, big washer and Loctite !

    Attachments:
    #39939
    rjy
    Participant

    E10 is as far as I know allowed for these engines, but I’ll switch to E5. Given the age of these engines, I was surprised and pleased that unleaded is OK! 🙂

    I took a picture of the electronic ignition module that’s fitted. It’s similar, as said before, to the chevroned article pictured above. I guess they all work the same way. I have ordered a replacement just in case for the princely sum of £12 (as I also have another ‘350″ which has points ignition). Could not find a “Meco”.

    The coil is as described above. Two LT connections, one earthed, one HT lead. The non-earthed LT wire goes through the pictured ignition module to earth. No kill switch. I will have to fit one, ‘cos it’s hard to stop the thing (when actually running) apart from by shorting the HT lead to earth.

    The odd thing is that it worked perfectly, twice, for maybe 15 minutes at a time. After, it stopped and wouldn’t start again. I will check to see if there’s a spark now it’s had a rest for a while.

    I took the coil off the day the day before running it, to check. It all looked OK, but perhaps I missed a crack in the insulation… but the odd think is it runs fine for a while, then stops and won’t restart apparently due to “no spark”. Perhaps the coil fails when hot?

    How on earth does the electronic ignition work? Replacing the points seems to be a matter of cutting off the points connection, putting the LT feed through the electronic module, and earthing the other side! What about timing?? Gah!

    I thought I might file off the threads, when needed, and re-cut with as big a diameter thread as possible, because the end of the crank would not be lost, and I could drill and tap internally at some other stage if need be. I don’t know how on earth people manage to butcher things like these threads. Grr!

    Attachments:
    #39941
    wristpin
    Participant

    America went over to unleaded fuel way before us, and all their small engine manufacturers were using hardened valve seats well ahead of us. They also offered the option positive valve rotation for certain constant speed applications such as generators and pumps. Your engine was made years before the introduction of ethanol adulterated fuel so go for the lowest E number available in your area.
    Your possible time / heat related failure may not be ignition related. When it stops, push it straight into a shaded area, disconnect the plug lead, remove the plug, hold the lead 1/4” away from the head or head shield, and rotate the engine with the recoil. If you get a spark, look elsewhere – valve clearances perhaps.
    There are a couple of eBay sellers for Meco units, but the Nova one seems to be favoured by Kohler users.
    When considering replacing a conventional points and condenser system with an “electronic” trigger module, I like to have the engine running satisfactorily before the conversion. That way, one can be fairly sure that the coil etc are sound.
    In the light of your issues with the flywheel nut, have you checked that the flywheel hasn’t shifted on the crank – sheared or partially sheared key?

    #39942
    charlie
    Keymaster

    For information on fuels and the damage ethanol can do see the FBHVC Guide to fuels.

    #39964
    rjy
    Participant

    When the rotavator stopped, both times – once with the plug that’s been in it for years, once with a brand new plug, no spark was visible. I have not checked since, I’ll turn it over tomorrow and see what happens.

    The magnetic rotor should be OK. After all, it works, and magnets don’t “come and go”. The cast iron blower/flywheel is a good fit, it pulled off the taper with a bang as I’d expect. There’s a spring washer type thing between the rotor and the blower/flywheel.

    I can’t fathom how the ignition works. With points, they break the current at exactly the right instance when the magnet’s passing the coil, but how on earth does the electronic device “know”?

    I might put the new electronic device on, if that seems a reasonable idea. It’s cosmetically different from the old one, but the wiring seems the same.

    #39966
    rjy
    Participant

    Well, I don’t know. With a brand new sparking plug, there is a spark. I would not say it’s a nice fat blue one, but it’s reasonably lively, and I think good enough. If I put the “old” new B6S plug in, there are feeble and faint sparks around the centre electrode’s insulator. I cleaned the B6S with washing-up detergent and water, also MEK, warmed it dry, and it sparks as well as a new one.

    The B6S was very black and shiny before cleaning. Perhaps the carburettor needs adjusting, although it ran reasonably well (albeit only for 15 minutes) before…

    Wretched thing.

    #39968
    enginear
    Participant

    With ref to understanding how an electronic ign system works if you go into google and ask what is inside or how an electronic ign module works there are some very good videos of these, just remember without magnets and electricity humans would be in deep trouble, and ask yourself one other question as you know metal is attracted to magnets and the earth has a magnetic field, but we are not made of metal so why do we stick to the earth.

    #39969
    charlie
    Keymaster

    The Green Spark Plug Company have a list of Technical articles amongst them is one about modern spark plugs fouling and shorting out It might be worth having a read through these.

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