When will I learn?

So then, it's official... I have a problem with rust.

I've tried to fight it, but I just can't do anything about it - might as well just give in and go with it.

On that note - I bought this today!





And yes, the pictures actually make it look better than it is I'm pretty sure it's a mk25 - but if anyone knows better let me know. I take it these have the engine number on the cowl? Like the only bit missing...

I gave a little go at turning it over when I was looking at it, the guy selling it said "look, it's got compression" - to which I replied "does it have compression or does it have rust?"

So I bought it anyway - hey, anything can be fixed, can't it?

Had a little look after dinner, the crunchyness on rotating it turned out to be the flywheel full of 'stuff'. I took the valve gallery cover off and it actually looked pretty good, no rust inside. Then I took off the flywheel and cleaned all the rubbish out and it turns over really nicely, valves open and close and it has compression!

Jolly good so far.

Then I took the head off - seemed like a good idea at the time - doesn't it always?

Well damn!




How the hell did that happen? That dark line around the top of the bore isn't really even a wear line, can just barely feel it with my fingernail.

The real shocker though is I think the coil needs rewinding - who would ever think a Villiers coil would fail?

So, better get on with the JAP so I can do another little job - maybe even this one!

Paul

looks to me too
like a MK20 or a mk25
please send me the long stamped on number from the flywheel and will give you some more info on engine

the only real difference is the size of the bore and piston

MK20 has a bore of 63mm stroke of 66.7mm 206.5cc hp from 1.5 to 2.7hp

MK25 has a bore of 70mm stroke of 66.7mm 256,5cc hp from 2.o to 3.4hp

any other help pm me as i have books and many mk20-25s in my project shed and spares to
thanks kev

Thanks Kev,

I had look on the flywheel but couldn't find any numbers... There is a timing arrow stamped and a small circle(?) that I couldn't quite make out because I only gave it a wipe with my finger - but I didn't take off the fan or the starter cup, would the number be under these?

I'll probably take them off later anyway and have a look.

Paul

Paul we all like a challenge some more then others

Stu.

stationary stu wrote:Paul we all like a challenge some more then others

Stu.

I can't say for sure until I get it opened up, but it should actually be less of a challenge than the JAP.

The only things I can see really wrong are the missing cowl (easy enough to sort out on this one) and the faulty coil. If I can't 'fix' the coil then I'll probably use an external one as a temporary measure, it doesn't do any harm and is dead easy to reverse if parts come up. There is also one mounting lug snapped off the sump, but I should be able to tidy that up and it'll be fine without it.

I'll let you all know how I get on, when I get around to it!

Paul

Forgot to say, this'll be another one where I won't be spending any sort of money on it. Especially not with how much I paid to get it...

You certainly don't like to make things easy for yourself do you!

I know where you are coming from though, I've got a heap of projects to sort out already and I contemplated buying another one a few days ago, luckily I missed the end of the ebay auction

Ianhw77k wrote:You certainly don't like to make things easy for yourself do you!

If everything is too easy, then where is the fun?

Plus, if something only needs a wipe down then I certainly wouldn't be able to afford it...

Well I can never resist a bargin so that's how I pick up my engines, I'm not so much bothered about the condition there in as it's work for later.
This is my latest bargin that I won on ebay last night for the costly sum of £10.50, it's out of a rotavator and not been started for a few years. It looking in reasonable condition and not very old.



Stu.

stationary stu wrote:Well I can never resist a bargin so that's how I pick up my engines, I'm not so much bothered about the condition there in as it's work for later.
This is my latest bargin that I won on ebay last night for the costly sum of £10.50, it's out of a rotavator and not been started for a few years. It looking in reasonable condition and not very old.



Stu.

stu
looks like a villiers c12 with wico/wipac electrics fitted and a reduction box too
nice little motor economical on fuel mine is ,just finished rebuilding engine in my waterpump set readyar to show and pass on to a youngster for getting them into rallying at a low price and since then i is on my fathers farm pumping over 900 gallons dirty water from sheep sheds and pens over 200 yrds to stream each day since JULY 1st so my work is being well tested lol lol
if you need any bits for it please pm asap as i have one stripped and going into the scrap next week as got to go for room
kev
kev

Kev not picking it up for a few days, only thing I can think that I'll need is a fuel tank but should be able to pick something up easy for that if I havn't already got one.

Thanks for the offer
Stu.

kevjhnsn wrote:looks to me too
like a MK20 or a mk25
please send me the long stamped on number from the flywheel and will give you some more info on engine

the only real difference is the size of the bore and piston

MK20 has a bore of 63mm stroke of 66.7mm 206.5cc hp from 1.5 to 2.7hp

MK25 has a bore of 70mm stroke of 66.7mm 256,5cc hp from 2.o to 3.4hp

any other help pm me as i have books and many mk20-25s in my project shed and spares to
thanks kev

OK then, it's a MK20. Whipped the head off and measured the bore - 63mm.

No number I can find at all... I suppose it could be under the starter cup, but the screws that hold that on are peened over... Maybe I'll find one when I start working on it.

Well, I've decided this engine is not having much done to it yet. All that's been done is: head off to inspect the bore/valves, a brush off to get the vegetation off it and removal of the coil to play with.

The coil was the only thing I really wanted to look at - it's a right mess... I ended up cutting through the gloopy goo and the windings and the copper was green to the core.

I have a cunning plan though - I'll let you know what it is later.

Now this sounds interesting.

Stu.

stationary stu wrote:Now this sounds interesting.

Stu.

If you mean my plan, it'll be interesting if it works!

A pair of glasses, a battery and a set of jump leads walk into a pub and the glasses go to the bar. The bartender says "I'm not serving you lot, you're already off your face and your friends look like they want to start something..."

Anyway, on with the plan.

I'm sure I mentioned before how I hate parting with money, well as I said the coil on this engine was really bad. I'm certainly not prepared to spend £60+ on a new coil, and I'm not even going to spend £20 on an ebay one - especially bearing in mind I only paid £9 for the engine and this:



That'll get driven by something once I dig a suitable run capacitor out of the shed...

So, I stripped the old coil and cleaned it up, then 'found' some enameled copper wire laying around in the garden.



That used to be part of a broken generator. Now if anyone else wants to try what I'm going to describe you'll need enameled wire, it's not worth trying normal wire 'to see what happens', I can tell you what'll happen - nothing. At all. Except you'll waste some time.

So I took some wire off that and wound about 250 turns onto the old coil core. I say about because I didn't count, there are around 45 turns per layer and just under 5 1/2 layers. It's not too critical anyway.



Then I got an old motorbike coil, a half-wave rectifier (diode) and some bits of cable and wired it all up like this:



And stuck it roughly to the engine like this:



Then I wound a rope around the starter cup and gave it a tug...

Took a while to pull that rope y'know.

I CAN HAZ SPARKAGES!!!!!

Well, not the most fantastic HT spark I've ever seen, but it's there, which is a start.

I'm reading about 3 volts off the self-wound excitation coil (or swec - the name I've given to the coil in the mag ) while pulling the rope. That'll be quite a bit higher when/if the engine runs. To be fair it's probably higher than that anyway but I can't keep it spinning long enough for the meter to read properly. I may have to 'adjust' the amount of turns to get a sensible compromise voltage to run the coil.

Stuff to do:
I do still have to play with the polarity of the HT coil as it isn't marked,
I think the AC wave generated by the swec may be asymmetric so I'll see which way works best,
I'll probably end up with a car type coil on it as it'll look better,
I'm thinking about putting in a smoothing cap between the rectifier and HT coil to keep the voltage stable.

But, my cunning plan worked, I proved my theory and I have sparks.

I've earned a biscuit

It all sounds very interesting but you lost me at enameled copper wire I'm sure you know what your talking about and it does sound as if you'll get the increase that you need.

Stu.

Well as a simple explanation I have either:

replaced the HT windings of the original coil with a double acting remote winding, or

converted the system to a battery and coil, but replaced the battery portion with what is effectively an alternator (giving rough DC due to the rectifier). Interestingly, due to the timed nature of the flywheel generator the coil does work with AC, but it's not exactly ideal.

Choose whichever of these you like, they are both technically correct!

Depending on what else I get told to do this weekend, I might time it up and throw some petrol at it, see what happens.

Paul

Ok, so I had a little time tonight and had a bit of a look...

I set the timing really accurately (put the drive side keyway to about the top, turned it 'some' (possibly 27 degrees, who knows?) backwards, looked through the hole in the flywheel until it looked like the points were beginning to open and tightened the nut).

Then I unbolted the inlet manifold, turned it over and put it back on upside-down. This meant it was open at the top.

Spark plug was next, so I did it up by hand (I couldn't be bothered to get a spanner out).

I wound the rope around the pulley and poured a lump of petrol down the inlet manifold.

Then I gave the rope a tug......





......Not a lot happened.....





So I put the rope back on and gave it another tug.......












It only bleedin' started didn't it?




Not for long admittedly, after all it was only a splash of fuel with no carb. So I did it again. And it started again.... I was pretty pleased with that, sat around in unknown conditions (not good going from the amount of crap on it) for an unknown amount of time and it fired up second pull with a home-made ignition system and old fuel that came out of a mower I got from the scrapyard 6 months ago.

Seeing as it was nearly 10pm I thought it best not to carry on. If I can get a bit of time tomorrow I'll make a really dull video of it running for a whole 3 seconds! I might even stick the carb back on and see what that does...

There's still a lot to do on the ignition though, I may have to put some sort of voltage regulator on it so I don't burn out the coil - that would also mean I could whack some more turns on the internal coil to get more low speed voltage and make it easier to start, although considering the ease with which it fired up tonight I might be fine as it is - I'll have to measure the voltage to the main coil when it's actually running and take it from there.

Apart from that, I don't think I'll have a huge amount of spare time for a little while to do any real work on it. I really should get the JAP finished off before I start this one properly.


To be continued - again.

Well done Paul great idea and it worked sorry I can't understand it all, electrics not my strong point. Looking forward to see what else you manage to do.

Stu.

Managed to snag another few minutes again!

I cleaned out the fuel pipe banjo fitting and fitted the carb, put a bit of pipe on and filled it up with fuel - here's what happened..... (I think you'll have to click it to get the video)



So, what do you think?

A little off-topic, but I've had a petrol flymo in the shed for a few months with a failed coil... It's got a 2 stroke kawasaki engine which is the same as on one of my hedge trimmers so I tested the engine by swapping the coil over.

As it has points (rather than electronic ignition) I think I'm going to try the same thing on that one soon - anyone interested enough for me to put it on here or would it be far too new? If nothing else it'll show the theory works on different styles of engine...

I know this is not exactly original and may be frowned upon for being a 'modification', but it gets an engine working that I couldn't afford to fix otherwise, and if I ever feel the urge to put it back to standard all I need to do is replace the coil, which is exactly what it needed anyway - no other mods were done.

Paul

looks like the rusty lump i won on ebay last.cost me a fortune of.£2.20