[sidevalve5]

Hi Andy,

I do not know the model the armature plate and flywheel came from. I purchased a Clifford roteo with a Mk25c engine about 15 years ago. The vendor was honest and said he thought the coil had packed up and suggested an external coil from a Honda C50 could be rigged up as a fix. Did try, but through lack of knowledge I think I omitted to remove the secondary windings from the duff coil. Also it was highly likely that the original coil still did not have enough primary windings to induce the secondary. The ratio needs to be around 100 : 1. A friend gave me the parts with the sheared shaft to see if the coil would fit. It didn’t, so I got a replacement that George Shead was selling at the time that required a little bit of work to fit. I have never tried to remove the sheared shaft from the flywheel to see if the woodruff key has bent over or sheared too. In fact I do not even know if there is one, it could be just a plain taper like the Mk25c. If so, its an example of someone over-tightening the flywheel nut.

David’s post has reignited (pun intended) my thoughts about the timing on my Kohler K181. The Condor was always a bad starter and it was not helped with the usual drag problem with belt clutches preventing the engine from turning over as rapidly as it should with a hand start. When I got the Ransomes Bobcat, I retired the Hayter. After I wrote my reply yesterday I did a bit of research and found a lot about timing the K series engine. Apparently unless the ignition is spot on, the problems I was having manifest themselves. One chap said he initially set the points to 0.020” and even reducing it to 0.018” with static timing from the flywheel marks made a vast improvement. Others say more accuracy can be obtained with a strobe. But the consensus was that just setting the points to 0.020” was not good enough, they then need adjusting to the timing marks. If using a static method, the old fag paper trick is not good enough, you need a multimeter. Many years ago I had a tuned Yamaha RD400 with a twin set of points and ignition timing had to be checked every 700 miles. I got a plug adaptor so a dial gauge could measure the piston position to 0.1mm and used the multimeter to see when the points opened. Am going to have a good look at the Condor this weekend and give the ignition timing a thorough checking over. Looking forward to it.

Grahame

[sidevalve5]

I had the opposite problem with a Barrowmix mixer that had a small Briggs and Stratton engine on it. I bought the mixer for the drum, as mine had started to rot away (tip, if you are going to store a mixer, do not leave any water in it). Thought I would get the engine going as it seemed like it had not had much work. Could get it to pop and bang, then run for a bit, but no power or even revs. Thought I would check the flywheel key, it is a soft alloy and designed to shear if the engine’s machine came to a sudden stop. It had a step in it which was similar to the 0.035” you moved the timing by. But in this case it prevented the engine from running correctly. Think someone had overloaded the mixer and the key partially sheared. Which was my good fortune as I didn’t pay much for it and now the engine runs as sweet as a nut.

Someone gave me a Villiers armature plate and flywheel with the crank sheared right off. It came from a water pump, the user did not fit a strainer to the suction hose. It pulled up a stone, stopped the impeller and with a steel key the flywheel’s momentum sheared about a 7/8” shaft as clean as a whistle. Have a Villiers Mk25c on a Clifford roteo, when I replaced the coil I only gave the flywheel nut a few light taps to tighten it up and glad I did. I hit a big stone, the engine stopped dead, but the flywheel moved on the taper, so no harm was done.

Yes, there is a little plunger rod on the Kohler that operates the exterior points and when it kicks back it is really vicious. Looking at the manual it appears that fine tuning the timing can be done by adjusting the points gap. But have not done this before, have always set the gap to the manual’s recommendations. Would be good if anyone has had a similar experience to me with Kohler engines and subsequently have got the ignition set up spot on to get them to start better. Am going to dig the Condor from the back of the shed this weekend and have a look. Don’t need a mower at the moment though. In the Vale of Evesham we have not had any significant rain since the end of Feb. The grass is not growing and feel for those who make a living from the land.

[sidevalve5]

That is very interesting. Have a Hayter Condor mower fitted with a Kohler K181 engine that’s always been a pig to start. The automatic compression release does not operate on every pull of the cord. Or it kicks back. It used to burn oil for fun, so I took the engine apart and then got a pattern re-build kit from the USA. After a rebore I put it together and the engine itself ran beautifully. Starting though was still a pain. I adjusted the ACP tab, made sure I still had a 6mm spark in air and the carb was still supplying fuel, but still no better. It’s not helped with the pull cord handle being under the machine’s handlebars. I then got a Ransomes Bobcat zero turn mower, so put the Hayter at the back of the shed.

Just checked the Kohler engine manual and the ignition should be timed to 20 degrees BTDC. Your post have given me some thought and will again have a look at the timing. If anyone has any tips on what to look out for on the Kohler engine, I would be very grateful. From what I understand they are often difficult starters. As the ignition is fixed, the spark excellent and compression was good, I mostly blamed the carb. But think that’s fine, but the timing could be out.

[sidevalve5]

Great you have a spark. The screeching sound is from the loose ball bearings inside the retractable starter. The fix is to take it apart, clean the dirt out and reassemble DRY. You may have done this already though. The dirt in one of mine has worn the aluminium tracks and balls. Cleaning did help a lot, but it still screeches sometimes and prevents the cord from going back in. A few gentle tugs on the cord and it does rewind. It used to do it after a few minutes work, the cord popped out too, which was a pain as I had to disengage the clutch, walk round to fiddle with it. But now, if it does it at all, it’s just after it has started.

A new diaphragm is a must for B&S engines if they do not start. After reassembly I would put your hand over the carb inlet and give it a few pulls. Then look inside the carb, you should see some petrol at the bottom. It shows the diaphragm has pulled up the fuel into the little reservoir in the tank and then the main jet has pulled it into the carb. Once the engine is warm, the coke off and the air filter refitted, you can tune it with the needle valve on the main jet. By ear you can find the ‘sweet spot’ between rich and weak. If you are going to use it for hard work, would screw the valve out by 1/8th turn.

Grahame

[sidevalve5]

Concur with Andy, get a good spark first, then clean the carb thoroughly and fit a new diaphragm. Have fitted pattern ones and have had no problem with them. If the ignition is a points type, its not the best design. I get to them by using an air chisel with a point fitted and put it on the crankshaft end. A put a prybar behind the flywheel, give the chisel a buzz whilst GENTLY putting pressure on the flywheel. If the combined points condenser, or the coil is duff. I would personally replace it with a transistorized module. Its a dead easy swap and the spark is much stronger. These small engines have a similar rev range and power delivery, so do not think swapping the original for another type will make too much difference to the machine’s operation. A good idea to fit a toothed belt to replace the original tyres.

[sidevalve5]

Bonjour Marc,

Une restauration fantastique, bien faite.

Meilleurs vœux,

Grahame

[sidevalve5]

Hi John,

It looks like you have fixed it. This is my experience of them.

Over the years have had several leaking Ewarts fuel taps. Did once get some replacement corks, but they were poor quality, still got leaks. Have tried PTFE tape, nitrile cord, soaking the original corks in an oil/paraffin mix. Nothing really worked. Have had a couple of taps where the threaded spindle with stop end had seized and then saw on ebay a chap from the USA selling an O ring kit. They worked really well, so I took the dimensions of them and then got some from a UK O ring supplier. They were FKM (Viton) Brown 75 ShA at 4.42mm ID and 2.62mm Cross Section. To fit use plenty of lube, fit 4, but if tight fit 3 and put in a small standard O ring to take up the gap. They have cured the leak on every tap I have fitted to them to, the operation is smooth as well. They cost pennies. But you have to get the correct sized O rings, or they may not work.

Best wishes,

Grahame

[sidevalve5]

‘You pays your money and takes your choice’ with mag testing. A ‘Proper’ test rig would be one that can rotate a magneto, be able to measure the voltage and current output of both the primary and secondary coils. Ideally be able to view the sine waves on an oscilloscope and check the spark gap in air with a 3 probe adjustable tester. For flywheel magnetos, similar except without a magnet passing over the coil, a current is supplied to the primary coil.

Without access to such equipment, only static testing can be carried out by measuring the resistance of the LT and HT circuits. This is carried out with a multimeter.

Condensers can be tested either with a megger or the capacitance function of the high quality multimeter. Have found a lot of ignition problems are caused by the condenser. As I do have a megger, I can test one. For those who do not have access to one, my recommendation if the LT and HT circuits seem OK, is to replace it. But I fit a modern polyester film capacitor with a Voltage Rating of 630v. Capacitance 220nF / 0.22uF. Can get 10off for £4.09p here https://www.ebay.co.uk/itm/301127883221?var=600476142172 I mount them on a small circuit board, but you may get away with a small piece of stiff plastic.

Testing a mag with multimeter is easy, it only takes a few minutes. If I find a fault in the coil, I replace it. If I still do not get a 6mm air gap spark, I replace the condenser with the capacitor above. For me, it’s worked every time. Although I there are some mags with a suboptimal windings on the coil and/or tired magnets. As yet, I have not had one. When I do I will trial again a single wire energy transfer coil system and get the magnets remagnetized.

[sidevalve5]

Hi David,

Great that with some more work you managed to get the carb to work well. From what I could see of the pictures you posted it looked like there were potential faults in the design. The float may have not moved freely up the central column, it could twist and then stick. How it pivoted against the needle meant it would not hit the needle square every time. Causing it to not operate as reliably as it should. But you have fixed it, brilliant.

Have often thought of fitting an aftermarket modern carb to an older engine. Was always concerned if I could fine tune it. You post rekindled my idea and after 5 minutes on the computer I found that there are a huge range of cheap carb jet kits available. May give it a go when I have time one day.

Fully concur with both your grandad and Andy about old stuff. If set up well, they are a joy to use. But if not, they are hard work to put it mildly. At times I used to hate using my Trusty until I got it sorted. Your tale of the MG6 putting your grandad up against a wall reminds me of hearing of someone killed by a Trusty. It put a chap using it through the side of a greenhouse, he died from blood loss. Find it really satisfying that often with a little tinkering, what some may regard as scrap can be used again. Operating in a smooth controlled manner.

Best wishes,

Grahame

[sidevalve5]

If you have not done it already, firstly I would remove the points, hone any pitting out from the contact surfaces, refit and set the gap to 0.015”, also clean all terminal connections. With the plug cap removed, hold the end of the HT lead 6mm from a clean part of the engine and see if there is a spark. If there is, you have fixed it, if not, close the gap until its 4mm away. I find holding the HT lead steady difficult, so have got an adjustable spark gap tester that was <£4, its one of the best tools in my box. An engine will start and run with a 4mm gap, but for easier starting and smoother tickover, you really need the gap to be 6mm. A good mag will achieve this. <4mm and the mag needs attention and personally I am not happy until I get it to spark at 6mm. If still there is a poor or no spark, a test with a multimeter is as follows: for LT Continuity, rotate until the contact-breaker points are open. Set the dial to 200Ω, measure the resistance with the two probes shorted together. The reading will probably be a fraction of an ohm and note it. Then measure the resistance between ground and the ‘hot’ side of the contact-breaker. Deduct the noted reading from the reading on the dial and the result should be between 0.5 & 0.7 Ω. A high reading indicates a bad connection or break in the low-tension circuit. A lower reading means there is probably a short-circuit in the contact-breaker assembly or in the armature. For HT Continuity, set the dial to 20KΩ, place the red probe on the pick-up or HT lead, the black to ground, the reading should be between 3 & 7 KΩ. If significantly higher there is probably a break in the HT winding, or a bad connection between the winding and the pick-up. If significantly lower, its unusual, but still indicates a problem. A lot of ignition troubles are due to the condenser. If the LT and HT tests are fine and you have access to a megger, the condenser should pass a 2GΩ @ 500v test. If you cannot do such a test, I would replace it with either a recently manufactured one, not NOS and certainly not second hand. As the wax paper inside them deteriorates with age and use. Or get a modern capacitor such as an EasyCap CU220 from https://brightsparkmagnetos.com/ which is my preference. In my experience they often perform better than old style condensers. Have had instances where a good mag with the existing condenser achieved a spark at 4mm, by fitting a modern capacitor the gap increased to 6mm with the subsequent easier starting and a smoother tickover. Resting a plug on the side of an engine to see if there is a spark is not a good enough test if ignition problems are suspected.

The above is the test procedure for a home mechanic who can use a multimeter. A multimeter will not test the condenser though. Others may advise you go straight to a specialist who may or may not have dedicated equipment. My advice if you are tempted to go down this route is to firstly get a quote, even testing will cost a fair bit. The above is free if you have a multimeter, about £8 – £12 if you have to purchase one. But it will be an investment as it has many uses.

[sidevalve5]

Hi David,

Have thought several times of fitting a modern carb to an industrial engine. Bought a cheap Chinese copy for a Honda for around £12 and was amazed of the quality and how they could sell it for that amount. Am not a fan of some older type carburettors, they are quite crude in comparison to more modern versions. The float/needle arrangement and the method (if any) of emulsifying the fuel is often poor. Could you send some pictures of the manifold and throttle linkage arrangement and I will try to think of what replacement carb may be suitable.

Off now to get a nearly new Locin 1” pump for £40. The Villiers/Alcon will be sat in the shed for a while yet I think.

Best wishes,

Grahame

[sidevalve5]

Dear David,

Fantastic descriptions and pictures of your precision engineering skills. You remind me of an old boy who does a few little jobs for me. He has made scale stationary, steam and aircraft engines from scratch. What he can do amazes me and he is in his eighties.

Without those abilities people like me have to try to work with what we can obtain. I had the problem of getting hold of some piston rings for a Gravely D. No chance as named spares, but whilst researching fell upon Hastings Piston Rings. After reading their very helpful technical guidance, found a set that fitted in their brochure. Although they were an American company, they had a franchised distributor in the UK. So ordered them. They could have also supplied some for a Jap 5, but in the end as Cox & Turner had them in stock. Purchased some from them.

Was told once Ford Consul pistons would fit a Jap 5. This was not true, but after the success with the rings I tried to do the same with specialist piston suppliers. Was hoping to find a way of getting a replacement piston when it was not obtainable as a named spare part any more. But have drawn a blank. I cannot find on the internet a catalogue where I can cross reference: bore, gudgeon pin diameter, compression height and crown profile. Does anyone know of a method of doing this. Where it may help David, or anyone else, is to obtain nominally obsolete pistons to keep their old engines running in good order.

My elderly engineering friend has a large and rare oil engine with the plug, or more like a pair of electrodes, sitting in a chamber outside the cylinder. It’s a lot cruder than the Rover one shown in your pictures. As for the carb, I would just fit a modern one if parts are no longer available. As I think some of the older types were just too rudimentary and unless in good condition, cause a lot of problems. But I am more interested in performance than originality. Others may take a different view and can well understand that.

Best wishes,

Grahame

[sidevalve5]

Hi William,

Am presuming the mower has a Briggs & Stratton engine. If so, I have found they sometimes need fine tuning with the mixture screw to run well. Have a 12HP model on a Ransomes Bobcat mower and even 1/8th of a turn on the screw can make a big difference. Do not think a normal compression tester is the best tool to use on hand start single cylinder petrol engines. They really operate best when the engine is running at least electric starter speed. The correct tester is a leak down type. But if you do not have access to one and I do not. I use the thin latex glove method. Fit the glove tightly over the exhaust and bring the engine onto compression. If it rapidly inflates, its the exhaust valve leaking. Do the same test over the carb inlet and if possible over the oil filler hole. This will test for blowing past the rings. The glove will inflate a bit, but if it rapidly does so, it identifies the problem area. You valve clearances seem a bit small to me. Would check the manufacturer’s recommendations.

Best wishes,

Grahame

[sidevalve5]

Hi David,

My Villiers engined Alcon pump is definitely 1½”. It does have a model number on it. I got it from a retiring market gardener, who sold me all the delivery and suction hoses too. It ran poorly, so I did my usual top end, points and carb service, it then ran well. It was noisy though under load and drank fuel. The Honda GX160 is a lot quieter and less thirsty, the Robin EY15 even better on both counts. The pumps have a superior performance than the Alcon too. So am on no particular rush to get the Villiers/Alcon combi running again. Very interested to hear that the pressure gauge had a red line at 20 psi and it rarely achieved that. It explains a lot. A friend of mine got 16 spraylines (they are each 15’ long) with a Villiers/Alcon combi and it never worked very well. He said he then got a Honda pump that ran the spraylines fine. He grew lettuce, watering regularly. He filled the fuel tank full and left it to run dry whilst he went off to do another job.

When I first took the Alcon pump apart, found the seal had all but disintegrated. Vulcan Water Seals were very helpful in identifying a replacement and were keen for it to be added to their database. The Clark pump had been purchased by a chap who had had his house flooded and wanted it in case it happened again. He then moved house and had no further use for it. He started the engine every few months, but did not know he was meant to put a bit of water in it to keep the seal lubricated. When I came to swap the pumps over I could see the damage done, so put a new seal in, again from Vulcan. Just for the fun of it I tested the suction with a vacuum gauge. This is when I found the Alcon pump was not achieving the recommended 20-25 ins Hg negative pressure. The others passed.

Had an idea to increase pressure by pumping from one pump, through another to replicate a multistage pump. But it did not work, the second pump was the Alcon and the Villiers engine struggled with the flow rate from the Clark pump. I did get an increase in pressure, but it was not enough. Quickly realized a multistage pump needs to have a calibrated flow from the first stage to the second and maybe a different impeller design too. My effort was doomed to failure.

Best wishes,

Grahame

[sidevalve5]

Hi David,

Have a 1½” Alcon pump powered by the Villiers engine. Got it in the 1980’s and used it for irrigation. But then got sprinker rotor heads that needed a higher pressure (30 – 35 psi) than my original ones. The pump also started to take an age to prime. Fitted a new seal kit I got from Vulcan Water Pump Seals, it improved the suction, but still the pressure was not sufficient. Got another Honda engined Clark pump (26 meter head), but still the pressure was not enough. So did try to link the two together, but I only got a small increase in pressure. In the end got a Robin engine Koshin pump (30+ meter head), it performed well.

Took the Alcon pump apart again and found the engine crankshaft was pitted with rust. I think these indents allow a small amount of air to get past the seal and effect the pump’s performance. I was going to go along a similar line to yourself and sleeve the crankshaft. But without your skills I was going to use a hardened stainless steel shaft repair sleeve. Proposed to fit it over the shaft then grind off the flange. What do you think of that idea.

Decided I would swap the Koshin pump and fit it on the nearly new Honda engine, the Clark pump onto the well used Robin engine. Found that the crankshaft on the Robin engine had grooves on it where the seal was in contact with it. Also the Clark pump seal was not in the best condition, so replaced it with one from Vulcan. Now have two pumps that perform well, although the Koshin is the superior one.

Dropped on some Evenshower Oscillating Spraylines and these operate at a much reduced pressure. In fact I now use the Clark pump and only need half revs from the Robin engine. The original pendulum operated oscillation valve was worn out and leaked everywhere. So make another from a pair of ¼” ballvalves. But the operation was too stiff for the pendulum, freeing them up caused leaks. Have just spent Easter Sunday making a new valve with a 3 port L configuration. Have high hopes of success and will be starting irrigation this week. It needs it too, in my part of the world near Evesham we have not have any significant rain for 6 weeks or more. Am going to put a pressure gauge on the irrigation system to see exactly what pressure the spraylines need. They are very satisfying to see operating, gently and quietly going from one side to the other in true 1950 – 60’s market gardening style.

Best wishes,

Grahame

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