factory

I'm a little confused too, are you missing a bearing or do you what to replace a damaged one? There are several different bearings used for the crankshaft, PTO shaft, con-rod & gearbox (if fitted) and different sizes with the various design changes made to these engines over the years. Some pictures may help identify which bearing you need. David

Having found a leaflet for a CARBRA hedge cutter that looks very similar to mine (apart from the engine), I no longer think this hedge trimmer was made by O&R. I now suspect someone has adapted it to use the O&R model 20A engine, the fuel tank fitted is from a Cox series 140 engine, same as on the engine shown on the sales leaflet. The series 140 engine was made by O&R competitor Cox, the series 140 engine was also used on a chainsaw & bike kit and was also produced by Roper after they bought the rights to make it. Here is the rest of the CARBRA hedge cutter leaflet scanned & converted to a pdf; CARBRA Hedge Cutters .pdf David

Did they have an on-line catalogue? I couldn't see any links to one, but I have just found more pictures (probably too late) here; https://imanauction.com/cox-collection-iac-12.1.html The lots included; two Tiny Tigers (one with replacement later style starter housing), a Chicken Power bike kit and a Meier Line chainsaw, they all look unrestored. Pictures attached below as they will probably disappear eventually. David

I noticed a while ago that the scanned pictures of the NIAE test report in the first post had reduced in size and as I now have an original copy of the test report, I have created a pdf from it; NIAE Test Report Ohlsson & Rice Model J Engine Published Feb 1964.pdf The NIAE tested a couple of O&R's between Jan-May 1963 & published a report in Feb 1964. They originally intended to run the engine for 100 hours to determine the suitably for agricultural use & the maintenance requirements, they concluded that the early engines tested were only suitable for intermittent use. The first serial number tested was 030957 (model J), it had problems with the die-cast gears being very badly worn, they got through two sets of gears during a 31 hour test & the first set of gears jammed up due to a broken tooth, the cork clutch lining material was also worn. They did tests on a couple more engines (model letters not stated); s/n 030987 with gearbox, this also failed with a broken gear tooth after 20 hours. s/n 030987 with direct drive taken from s/n 030993, test abandoned as the PTO shaft wouldn't stay tight on the taper. s/n 053595 with drive through clutch, this was the longest test (50 hours), it mostly only had minor problems. O&R stated that the NIAE test was inappropriate for this engine, which would have been more realistically tested in complete equipment with normal operation times & intervals. They also made some design changes between Oct & Dec 1963, these included; an improved clutch & steel gears (were die-cast). more needle roller bearings with steel cages (were plastic). bigger exhaust ports. plastic reed valve (was metal). primer button on carb (a kit was available to update earlier engines). governor vane modification. fuel/oil mix changed to 24:1 (32:1 now recommended with modern oils). quadrant speed control on carb. The U.S. Department of Agriculture tested the direct drive Paradox pump in May 1964 and managed a 99 hour test with only a failed coil & a new set of piston rings being required. General maintenance included a couple of replacement spark-plugs and de-carbonising of the exhaust ports after 25 to 35 hours of continuous operation. See the previous post for a link to this report. David

Found an air cleaner/filter on ePay, the seller thinks it's a muffler, which the pictured part isn't; https://www.ebay.com/itm/Orline-M123-Chainsaw-OEM-Muffler-/151587552778?rmvSB=true It doesn't come with the fixing screw, but that would probably be attached to the chainsaw carb it was removed from, as the later air cleaner screw was riveted to the carb. They also have the muffler advertised as an air filter. David

I would be interested in seeing the instruction manual, are you able to scan & add it as a PDF? A forum update a while ago lowered the maximum resolution of pictures on here, any manuals posted this way are pretty much unreadable now. I think most manuals I've scanned & posted on here are PDF's, which are unaffected. O&R changed name to Advanced Engine Products sometime around the mid 1970's, tools with the renamed AEP engine were still being advertised until around 1978, but I haven't found anything later than this yet. The shark 60 uses .60 model engines, seems the O&R powered helicopters were discontinued, but they offered conversion kits for the Hughes 300 & Shark to use .60 engines, see the advert below from this website; http://www.vrhc.co.uk/rc helicopters/USA/Du-Bro/Du-Bro.htm David

The serial number dating information from the "small engine service manual" is only relevant for engines made after June 1967, before this they used a sequential numbering system, we can only estimate the dates for these engines based on information from original documentation. The NIAE tested four engines with serial numbers ranging from 030957 to 053595 between Jan-May 1963, with this information both of your engines should actually date from around late 1962 to early 1963. David

Click on the envelope symbol next to your user name at the top right of the page for sending a PM. Webhead should have the carb diaphragms & check valve, but probably not the air filter assembly, which is one of the most commonly missing parts and replacements are very hard to find. David

$35 was a bargain for the other engine, you probably couldn't buy the commonly missing spares for that (which were still on it) and I suspect the missing flywheel would have been much easier to find than a coil too. This should probably be in the O&R section, the NIAE test was intended to run the engine for 100 hours to determine the suitably for agricultural use & the maintenance requirements, they concluded that the early engines were only suitable for intermittent use. The first serial number tested was 030957 (model J), it had problems with the die-cast gears being very badly worn, they got through two sets of gears during a 31 hour test & the first set of gears jammed up due to a broken tooth, the clutch lining material was also worn. They did tests on a couple more engines (model letters not stated); s/n 030987 with gearbox, this also failed with a broken gear tooth after 20 hours. s/n 030987 with direct drive taken from s/n 030993, test abandoned as the PTO shaft wouldn't stay tight on the taper. s/n 053595 with drive through clutch, this was the longest test (50 hours), it mostly only had minor problems. O&R stated that the NIAE test was inappropriate for this engine, see below for more info & the design changes from Oct & Dec 1963; Note that the carb primer push button assembly was available as a kit to update earlier engines, so may not help identify engines made before Oct 1963, but as you've had the gearbox cover off you should be able to tell if the gears are die-cast or steel. The model J featured in the engine rebuild thread is one of these earlier engines with the die-cast gears & cork lined clutch. David

Still available according to their website; http://www.gsparkplug.com/1x-ngk-copper-core-spark-plug-cm-6-cm6-5812.html Seems to be the spark plug used on the 1960's Honda E300 generator. The parts list that came with my Tiny Tor is dated August 1964, the next update of the parts diagram I have is dated November 1965, so a date of around 1965 is probably right. They only used the fourth threaded hole in the tank on the earliest engines, which had a stud/nut fitted below the carb. The different screws fitted here are none original. I guess they never changed the tank design though. Steel bluing giving a black oxide finish is not the same as oil blacking as far as I know, the bluing process involves various chemicals depending on the process used, oil can be used at the end of the process for rust prevention; https://en.wikipedia.org/wiki/Bluing_(steel) https://en.wikipedia.org/wiki/Black_oxide Have a look on youtube for bluing of guns or knives to see the process. Looks like there are two methods for oil blacking, dipping heated parts in oil or baking oiled parts, some info here; http://www.practicalmachinist.com/vb/general-archive/oil-blackening-rust-protection-84713/ David

Exactly what I thought, I guess original spares were probably more difficult to find before the internet existed, especially in countries with few or no service shops or parts distributors for O&R's. David

I guess you bought the unused looking Model J engine (with 900rpm output gearbox) with no coil that was on ebay, if it was made before October 1963 it probably has the plastic bearing cages in the engine & die-cast gears in the gearbox, the NIAE tested a couple of these between Jan-May 1963 (report published Feb 1964) and had quite a few problems with the early ones. Possible source of an untested used one here, I would ask the seller to check the resistance of the secondary is OK before buying. https://www.ebay.com/itm/Sears-Mighty-Light-Orline-Chainsaw-OEM-Coil-/161674949894?rmvSB=true David

More pictures here but can't see the O&R's; https://www.estatesales.net/MO/Salisbury/65281/1732494 I guess a full catalogue will appear on the auctioneers website here soon; https://imankc.com/current-auctions/ David

Don't panic, you don't need to take the spring out, it sits in the centre of the starter reel bearing, if it is that part of course. Could it be a non original replacement for part 131? The carb disc is a very thin piece of pressed aluminium or a loose flat disc on most engines, later ones can have a smaller diameter flat disc glued to the diaphragm. Could we please have a picture of the other side of mystery part. David

I'm not so sure it's from the carb, I think it maybe from the starter (part 131 on the diagram below), but it depends on the exact measurement & thickness, I can't tell from your picture if it is flat or not either. Here are a couple of pictures of this part (listed as crankshaft thrust disk) which often falls out & is often missing too as a result, I did measure one earlier but have been distracted since & have forgotten, will check it again tomorrow. David

The spring keeps the adjustment screw from moving due to vibration from the engine when running, your replacement looks very similar to the original. I guess the NGK CM-6 should be OK as it was running with one before, it's about 2mm longer reach (the threaded part) than the Champion UY6 . I did buy a selection of alternates (AC 104, Lodge C10 & KLG TEN50, all NOS) from the Green Spark Plug Company, but they have mostly all sold out now. There is a error with one alternate listed on their website, the Wipac P4 is too long and is 14mm not 10mm. Yes the engine serial number can help with dating, but we can only estimate dating of engines made before June 1967 when they changed the sequential numbering system to a coded number system that gave the year & month of manufacture. I would estimate your engine dates from around 1965. The engine on my Tiny Tor (which started my collection) has a serial number close to yours (086359), old picture below. There is no information for the paint codes O&R used in any of the original literature I have, I guess they wouldn't help much as you would need to convert them to the equivalent European paint code. Some of the red starter housings on my engines have also faded to an orange/red. Pmackellow on here has repainted some of his O&R's, I think he uses standard rattle cans from Halfords. The air filter & exhaust muffler were not actually painted, they were finished by bluing, look up "gun bluing" for information on how it was done. Kits are available for bluing steel but I've not tried any yet. David

You've done a good job repairing the magneto coil wiring, I didn't bother hiding the epoxy resin at work, but would have used one of the old Humbrol model makers paints I have, it seems to be the only paint that hasn't gone bad with decades of storage. I also found smaller internal diameter fuel line is better, especially as I've not found a source of the thin wall type originally used, it must be available somewhere as I did see some similar (but even smaller) tubing inside a pressure tester from the 90's at work. The suggested fuel/oil mix is 32 to 1 with modern two stroke oils. It's up to you if you decide to repaint the engine starter housing, but I prefer to keep the original paint & decals if possible with my engines. What is the type of the NGK spark-plug you have used? The only thing I've noticed from the pictures in the last post is that you are missing the carb idle screw, it's a #6 screw same as those used on the starter housing but with a thread length of 7/8", it also has a spring as shown in the picture below, it won't stop the engine from running without it though; The lower holes are not used on the Tiny Tiger, they are used for the throttle cable on some tools & the Chicken Power bike engine. Your engine does have the letter B for the tank mount model (you asked about this before) it's next to the serial number in the picture below; David

Very few O&R's that have been used for RC models seem to have been converted for glow, the adaptor/bushing for using 1/4" glow plugs in the 10mm or 14mm cylinders aren't very easy to find, seems people either have to machine one to fit or find somewhere selling them. I did however find one place that has some ready made adaptors/bushings that may or may not be suitable; http://www.thunderboltrc.com/index.php?main_page=index&cPath=100_183 As these Helicopters aren't exactly common (working ones even less common) it may be a good idea to contact the owner of this one on youtube for advise, reading the comments it seems they aren't a big fan of O&R engines though. There is also an RC airplane that someone on youtube has built using an O&R chainsaw engine, it runs with the original carb & magneto ignition too. I do have a couple of O&R's with different carbs that were used in model boats, maybe I should add some pictures if anyone is interested, one is a K&B and the other maybe a Waltron, both are standard spark ignition & air-cooled. There was also a heavily modified O&R with an Irvine carb sold recently on ePay. I now have (thanks to Webhead) a Tillotson HU carb that O&R/AEP used on a weed wacker, I plan to adapt one of my spare engines to fit this carb and will update the thread here with my progress; David

I've done some resistance measurements of the stator windings of two 110V Tiger Tigers & the 230V Tiny Tor I have. The readings confirm the high/low voltage windings are connected together & everything is centre-tapped from the + output terminal. For the 110V Tiger Tigers the total resistance of all the windings (measured across the 110V outlet) was approx 5.7ohms, measuring from each side of the 110V outlet to the + terminal gave readings of approx 2.7ohms for each half. For the 230V Tiny Tor the total resistance of all the windings was approx 28.5ohms and the measurement for each half wasn't the same (14.7 & 15.2ohms), I don't have another to check the readings against as I had problems with the 230V output being low last time I tried it. I suspect it has a bad connection somewhere. I opened the Tiny Tor to measure the low voltage windings as the diodes prevent measurement from the outside, readings for each half were approx 0.3ohms after deducting the test lead resistance. All the measurements were taken using the lowest resistance range on a quality US made multimeter, which I check against a lab-grade decade resistor box periodically. I used to have a cheap chinese multimeter which was totally useless for low resistance measurements, you got different readings every time using the lowest ranges as the switch contacts are very poor quality. Better readings for the low voltage windings could be obtained using a low-ohmmeter as the measurements are at the bottom end of the lowest resistance range on the multimeter. I do have a nice vintage one but it's currently on the round-tuit pile as it doesn't work. Here is a DaveCAD diagram for the internal wiring of the 110V Tiny Tiger; There isn't much space for the wiring inside, I soldered the wires to the diodes on the Tiger I repaired as I didn't think there was enough room for connector blocks. David

Yes if wiring was reversed, the exposed battery charging terminals would have 110V across them, the diodes are probably only rated for low voltage (so could end up short circuited). David

The wiring for the AC 110V outlet has plastic insulation (probably supplied with the bought in 110V outlet) which rarely goes bad in vintage electrical/electronics, rubber insulation on the other hand always seems to eventually turn to either dust or a gooey mess as you've found. We even had a modern rubber cable fail on a 2007ish Weller soldering iron at work, the inner cores crumbled to dust causing a short circuit & blew the fuse. The two items in the casing with solid non-insulated wire leads are push fit diodes for rectifying the AC voltage to DC for the low voltage battery charging output. These will be connected to the thicker windings of the stator to provide the higher current required for charging. The ground lead is the wire on it's own on the other side of the stator. The AC 110V outlet will be connected to the thinner windings of the stator, be careful not to snap these, you may want to re-secure the cables into the windings with lacing cord as they were before. Thinner cable from a scrap mains lead would have been fine for connecting up these, as the maximum current drawn will be much lower. As for the the thin wires connected to the thicker winding, I've suspected they were as I got strange resistance readings when measuring mine. I will post a diagram of how I think it's all connected up when I've done some more measurements on mine as I didn't make any notes at the time. David

Not sure I can help much as I don't have any O&R's with either of those carbs, a few years ago I nearly got a glow converted engine with the Octura carb, but the seller messed me about (and presumably several others as their ebay account soon got terminated). I've only seen two O&R boat engines with the Octura carb so they must be quite rare. Likewise the O&R with the Du-Bro carb is just as rare. Presumably a similar mixing ratio for glow fuel would be required, what do the modern glow engines of similar size use? Just be aware of early O&R compact engines with the plastic bearing housings as they could potentially react badly with some fuels/oils. The only O&R's that I aware of having problems with glow conversion & nitro fuel were the much older & smaller Ohlsson model engines that were commonly used in model planes, broken con-rods & cylinder head failure being two problems with these engines. David

The generator stator windings do look more of a mess than usual, the rubber insulation of the wires always seems to disintegrate when disturbed, did the wires snap from corrosion too? If you can identify the high & low voltage windings, it should be possible to connect up new wires, if you can find some good condition wiring to connect up to of course. Be careful to not damage the insulation on the stator windings. You will probably need to clean the wire ends of corrosion for easier soldering, I recommend using a lead alloy based flux cored solder (not that modern unleaded solder rubbish, which requires more heat & has known reliability problems, it corrodes very easily too). Tin the ends of the wires with solder before joining together and sleeve any joints with heat-shrink tubing to prevent shorts. Here are some pictures from the restoration of my Tiny Tiger, it required the crumbling rubber wiring repairing, I took lots of pictures before disconnecting the wires and used different colour heat-shrink sleeving for identifying the low & high voltage windings. David

There are two windings in the magneto coil, a low resistance primary winding with a low amount of turns of thick wire and a higher resistance secondary winding with many turns of very fine wire. The two wires connected together are one end of each winding, these are grounded via the metal core of the coil, as they are not insulated they may still be connected together inside. The thin insulated wire is other end of the primary winding and goes to the insulated bolt for the contact breaker compartment, the stop switch & capacitor wire are also connected here. The high voltage end of the secondary goes to the spark-plug, the insulation of this wire looks damaged (heat-shrink sleeving can be used to repair this) and the plug cap is also missing. I would check the resistance of both the primary & secondary windings if you have a multimeter and post the results here. Not sure how easy it would be the open the casing around the two ground wires, you don't want to damage the insulated wire if you try or break the very fine secondary wire. I used to open and repair small potted transformers (which were unavailable/obsolete) at work, the plastic casing could be broken off around the faulty area, gentle use of a small electric heat-gun to soften the potting compound, which could then be scrapped out in small bits to reveal the connections for re-soldering, araldite was used to replace the potting compound to complete the repair. I don't have most of the equipment to do this type of repair at home. The number 151 stamped on to one of the crankcase flanges is the engine type, it represents the engine specification & options, I have a Tiny Tor (same as Tiny Tiger) that also has a type B151 engine. The letters were used on early engines, B is a tank mount engine. There were letters or numbers used for many standard engine types with different options of tanks, various gearboxes, clutch and mounting types. Diagrams & parts lists for the standard types are usually in the master service manual, many manufacturers of tools & equipment with these engines would have ordered a custom specification engine. David

I've also got some parts on the way, it's taken about 4 days to get from the US to the ParcelFarce depot in Stoke which seems quick, it will probably them another two weeks to move the parcel the last few miles knowing my bad luck with them . From experience it can take an extra week or two for international shipping between Black Friday and the new year. David