Marvil moments

Sep 08, 2010 1 Replies

I bought this



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and there were quite a lot of spares in the job lot.



I think the Jacobson fuel tank was a red herring and that it didn't originally come with the Marvil mounted upon it. However, that will not stop me from finishing it in that way, if only to demonstrate that the Marvil does fit the bolt holes and carb pick up pipe uncannily well.



I spent some time on it this week and found that the rod that was fitted was worn in the big end, but the spare rod amongst the bits is fine. Now fitted. It was a little bent, but a light tap with the padded hammer (it is a bronze casting) brought it clear of the crank web.



The magneto side main bearing is a little noisy, but it isn't for the work it will do after all. The drive side bearing is held in a big bronze casting, a very solid bit of metal that also forms the seal on that side. It is a light drive fit over the bearing. The BSW securing bolts bolts were missing, but finding some replacements was easy enough. Finding thread to screw them into proved harder in two instances, but I can pass a 5/16" drill right through the case and fit nuts on the far side without difficulty.



I have another Marvil on the bench, a Century engine with a proper carb and top petrol tank The spare crankcase that came with the eBay purchase has the same kickstart bracket but it isn't broken like mine is! It is sadly without any hint of electrikery at the end of the lead and I was not surprised to find an equal lack in the new one. Experiments with a 9volt battery and a multi meter give hope that the coils are OK, but just in case, I have sent them off the the nice man at themowercentrehailsham.com (advertises Villiers barrel coils in SEM) who was kind enough to say that he'd check them for free. We'll know tomorrow probably. My money is on leaky capacitors and weak magnetism in the flywheel. Is there anyone in the Bristol area who has a magnetizer that can restore their falloram?



The barrel and piston are fine & it did have compression before I took it to bits. An unusual feature is that above the top ring is a steel ring set in the ring groove. It isn't a compression ring & has a dimpled face without visible join.



The carburettor is not the usual Marvil type & I've not looked at it yet, but it appears to be all there.



Well, that's about it for a two stroke innit?



At the same time I bought a Maxtor unit, a Marvil driving a dynamo & mounted on a little sprung trolley running on pram wheels. They were used to drive a hedge trimmer. I was interested to see that the base board is a single piece of 3/4" mahogany. Although the engine was unbolted for transport, it is complete and simply needs a good clean and the manufacture of a steering column!



Regards,


Kim Siddorn



Since I wrote last, I have removed the dynamo, found that the spring was missing from one of the brushes but the brush was actually kicking around in the bottom of the case. I found an exact match for the spring from my box of springs recently bought at Aldi. The commuter was quite badly grooved but careful work with some files and a broken hacksaw blade cleaned it up very well. I re-insulated the armature and field calls with my customary coat of red epoxy resin paint warmed in the oven fort an hour whilst Hazel was out!.

It turned out that I was right about the condensers as both of the ones fitted to the points in both engines were knackered.

What with spares and the ones which came with the engine, I had 4 coils to check. One of them was fit for further service but the other three were either lossy or open circuit. I have obtained two and had the condensers replaced. As a matter of course I have had a fly wheels remagnetised although they were not as bad as I had suspected. All this work has been done by Martin Dry our local magneto man and I shall pick them up before the end of the week.

Regards,

Kim Siddorn

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