Morrisoft

Could it be the crankshaft thrust disk? Part 148-3. Item 15 here.

The wear marks on both sides correspond with it having sat between oil hole and flywheel bolt. The other side has markings to match the recoil housing oil hole. The wear is only superficial for the most part but the pictures give a good idea of what orientation it sat in.

You're spot on! That explains the strange wear markings on this too! (Flywheel bolt spinning against it!) Top detective work there. Glad we sussed that one. Can replace it now, although, I'm wondering if it's all that necessary? The recoil seems to function perfectly happily and with the spark removed the engine spins up no issues without any apparent issues inside the recoil housing while the flywheel is spinning. I remember putting the recoil spring back in all too well when I fixed that way back still in the Philippines. Was such a pain to get seated properly. My hands still bear scars from it. I will investigate how easily replaced it is.

Good evening David. I think you're right, the spring looks very close to the one on yours. I have a further 7 of these if they're every needed by anyone. Interesting - the very same supplier I used for the NGK. I think maybe I took their last CM6 then, as they didn't have any others on their eBay store. It's certainly 10mm which is good to have confirmed. Almost identical to the one it replaced other than a slightly different washer on the thread. I had thought around 1965 as this was when the gentleman who owned it mentioned purchasing it, just wondered if there were exact dates but a confirmation of 1965 is suffice. It's interesting to note that yours too has a different screw for one of the 4 tank mounts. Mine is simply a hex bolt of the same length, I assume due to lack of clearance around the engine for a screwdriver to reach it without completely dismantling all shrouds first. Is bluing like oil blacking, or are they the same think by a different name? Tempted to give it a try if this is the case as I've done this before. Cheers,

I had thought the carb disc was bigger? This is only 10mm approx across. Very little compared to the size I'd been assuming the disc is from other pictures/posts? If so then this is good news - I'm surprised, didn't come from within the carburetor, I remember that much. It appeared at some point during the rebuild for sure, all parts have been kept in small plastic tubs (a lid of which I used to photograph this piece), is it possible its come from somewhere else?

This is the link for the original coil assembly: https://store.chainsawr.com/products/o-r-engines-ignition-coil-a-149-3-new Hopefully this link doesn't violate any rules with admin? Please remove if I've overlooked something. As mentioned I find the price to be somewhat insane, you can get an entire engine for not far off the same price! In terms of alternatives, they wouldn't be a bolt-on option and may require modification. I can get some links if you struggle to find anything, most were found on a popular auction site, under a 'small engine ignition coil' search. Would be interested in following the build if you DO decide on nitro. Keep us posted Cheers,

Do you have one you want to replace or are you completely missing this part? They seem very hard to come by, although I possibly know of one going for around $90, which seems rather steep to me. What engine do you have, I've searched far and wide for alternatives and found *some* that may be suitable.

Many happy returns to the birthday boy

Ah! I think this works nicely. Spring is a little tougher than I'd imagine it needs to be but at least we know it won't move on its own. Oh. Also. Quickly. Does anyone recognise where this is missing from? Can't quite place it from the exploded diagrams. I am assuming it's from the engine but can't fathom where exactly.. Cheers

Hi David. Good spot, hadn't noticed the idle screw. I most likely have a spare, certainly have a screw but not sure about another spring. Does the tension for the spring matter? Might have a few tougher ones.. I had thought all those holes were for various other applications so I'm glad you noticed that was missing. The NGK spark plug is a replacement of the original that came with this particular engine, a CM-6. They're cheaper than the champion plug alternatives and since it ran with one previously I figured why not. I also prefer the shorter profile of them to the champion plugs. I've added a spark plug clamp and some more heatshrink today. Happy with the results. I ordered some gasket paper, since I've done everything else, I figured some proper gaskets in the carb etc, can't exactly hurt. Bonus, paid for A5 sheet, received an A4! In terms of the engine, yes I remember asking. It's a Type 151B, engine number 086792. Is there anything else that can be gleaned from this aside from what have been mentioned already? Manufacturing date perhaps? Just awaiting my last shipment from webhead, (diaphragm disk and Mylar check valve) and a test run can be done! If I did decide on repainting the recoil housing, does anyone have the specific paint codes for O&R Red? I assume for the muffler/air filter housing, black, any high-heat exhaust paint will suffice? Cheers,

Time for an update! I had to bite the bullet and rewire the ignition coil. I was able to dig enough away as per your suggestion. I then soldered a new fresh length of wire to them both. The longer one was for the new stop switch wire. Also got some new fuel line too. 2mm inside diameter in red, this wasn't intentional but suits the engine nicely. Rather snug on the tank nipples, no need for any clamps! May need to shorten the carb fuel feed as it's a little wedged in there. We'll see. Epoxied the HT lead base and stop switch and armature loop for long term stability. Really didn't like the way it looked, almost like Vaseline! Managed to sort this out nicely with a 'paintbrush' style black permanent marker. Also ordered a new spark plug shoe/boot, couldn't get them in singular form, so if anyone needs one, I'll have 3 spare. Shall fit this once it arrives. In two minds as to whether I should paint it fresh or keep the rustic original look. I had a spare spring and washer and, it seems functional. We shall see. Everything is now virtually finished. I'm just waiting on one last part for the carb now. Few more bits arrived this morning too: Any thoughts, or last minute things you can think of to check before it comes to running it again for the first time? Cheers,

Quick update with things.. Yesterday I managed to finally clear virtually all the goop from within the petrol tank, the fuel nipple with inline filter unfortunately remains blocked at the moment. On it's third soak of petrol as we speak. The stator rewiring is now complete as per your guidance regarding high (thin)/ low (thick+thin) orientation etc. Many thanks David! Pictures are below, it was an incredibly tight fit once putting the two back together. I only hope the soldering is up to the job. How easily it will go back together, given the difficulty involved in getting it separated, remains to be seen. More good news, this arrived with many thanks to webhead for his help. Just waiting on the diaphragm and needle-valve/spring and this should be good to give a test run with a temporary tank, unless it does finally unblock first!

Ah brilliant. I'm glad you clarified this for me as that would have been interesting when firing it up for the first time. Am i correct to assume it would simply have reversed the way outlets functioned if I'd wired it the other way around, making the 12v outlets 110v, and vice versa? Look forward to seeing the diagram, I can continue to replace/reinstate the wiring for now. I shall use different coloured electrical tape to enable me to identify the lower/higher voltage wiring as I only have black heatshrink and white cable of the appropriate gauge at the moment! 🙈 This is how things stand at the moment: I will clean and tin the connections ready for soldering to new lengths of cable. In terms of clearance I imagine the space for cabling, once reassembled, is slightly tight so I'll try to keep these as short as I can work with. Many thanks again David, you've been a tremendous help thus far!

Now that looks brilliantly useful! Wouldn't mind one myself 🤔

David you're an absolute diamond my friend. Pretty sure you read my mind with the pictures as I was going to ask if you had more. Fairly sure I can rewire from these pictures, I've stripped back all the crud and mess and gotten down to where the wires meet the windings as you'll see below. Some spare speaker cabling came to the rescue with the rewiring, so far so good. Unfortunately I only have lead-free at the moment but plenty of solder flowed nicely onto the two outputs shown below. Interestingly enough those two original pieces of wiring survived without corrosion or even the insulation cracking, still fairly supple so I've reused these as the copper was nice and clean after cutting them free of the old crimps. I'm going to use cable junction blocks to reattach the the two to the nipples inside the casing. Am I right in thinking the lower voltage windings clamp down to these? On the core itself I have two sets of wiring - both bottom leads connect to a thicker and thin winding, whereas the two upper leads connect to singular thin winding - I'm just hoping to confirm before final rewiring/soldering occurs. See below. Cheers