OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions on Other Engines TROJAN MAJOR - Motor Fitted To Ogden Rotamatic

I need some help, I have a Trojan Major engine fitted with a Wipac Series 90 Magneto. Pic below is of the electrics



Now IanOZ has helped me out via messages but what I need is a pic of the electrics from the Trojan Major engine as it has the magneto mounted on the inlet port side giving it a clockwise direction. Maybe any rotary mower that has the Trojan mounted Flywheel up will be the same.

What I am suspecting is that my coil should not be at the bottom as I have spark but not at TDC. The plate mounting only has two holes so it will only fit one way or the other but I am not sure so would like to compare electrics with a working one. A big ask but I am grateful for any help.

Hello Paul

All I have is an illustration of a Major.
It shows the coil at the 2 O'clock position.

Sorry I can't be of more assistance.
---------------------------------------
Jack.

Thanks Jack, I have the same pic in one of my mower digests. With my coil at two my points will be at four which is not consistent with the picture. Makes me feel that my set up is perhaps not original a photo would be conclusive as to what should be where.

Thanks for helping

Paul, I thought that the coil, itself, was fitted to the wrong stator core.

See:-

http://www.brightsparkmagnetos.com/easycap/universal/wico-pacy_series_90.htm

http://www.tanygraig.force9.co.uk/John/wipac1.htm

You just might be right there Jack, shifting the coil would also bring the coil lead into line with the exit holes in the back plate. Good to have another set of eyes look at a problem, I will give it a go tomorrow. Thanks

Yes

the exit holes for the HT lead was one thing I noticed.
I love the lighting coil for automotive applications.

I wasn't aware you had an Ogden Rotamatic. A very rare machine!

All very interesting.
-----------------------------
JACK

I have the engine, cowl and fuel tank. If a base ever turns up I am ready for it :-). I will post a pic of the engine unit when I get it running. Hmmmm optimist I am !

Hello Paul

I see. These are such a handsome and interesting machine.
I hope one turns up.

Looks more like a moon buggy than a mower, very space age.

Nearly going, broken ring so I fitted another good piston and bore off my junk motor then found a cracked rear seal so I swapped that as well. Once I get it running I will fit new rings and seals, bearings etc.

It wants to go and nearly does but just won't, pulled carby down again and checked timing but to no avail.

G,day Paul,

I was giving your magneto thing some thought. Did you end up swapping the coil position?

Reason I ask is that you say you had spark but not at TDC. If you had spark then the magnet neutral to points timing must have been at least fairly right - and changing the coil position would have thrown that out the window?

Just curious.

Cheers,

Cheers.

Hi prd,

Thanks for your help, I had spark but it seemed to be at BDC. I changed the coil and now have a very good spark and the motor is timed correctly. Points just start opening a few degrees before TDC and fully open at TDC.

Still not convinced it's getting a proper dose of fuel, a lot of cranking and the plug is not wet ?

OK, that is interesting. Not what I was expecting but your new coil position agrees with the photo in the motorbike link.

Gotta confess that I would have blasted in and flipped the whole thing on the 2-screw mounting if I'd been faced with that.

Sounds like your annoyingly close to a goer. Hate it when that happens.

I did flip it but it was a no go, I am still not sure if its position is right. A photo would be conclusive. It wants to go with the drill spinning it over but won't carry itself. I have pulled the cylinder off again and tipped it up and a lot of crap ran out. I am going to split the cases and replace the bearings, seals and gaskets, clean it all out. There could be that much carbon and rubbish down there that's it's destroying the fuel mix.

Bearings are no problem, they are the same as Victa and I have loads of spares. I will try the bearing place for seals and make my own gaskets. Rings not to sure about. Once The engine unit is sorted it one thing off the check list.

Hello Paul and prd,

I'm pretty happy that the coil is now on the correct stator plate core.
The second link also showed that as well. I just wish the design was more
'service friendly', making it impossible to fit the ignition coil or
lighting coil (if applic.) in the wrong place.

Here is a reconditioned one from Villiers Spares UK:-


[Source: http://www.villiersparts.co.uk/wip.html ]

p.s. Paul, I have added this page to the Master Record:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=60982

Yes Jack I would say the electrics are sorted. Mind you after draining the crankcase out I bet it would go. With all that was in the crankcase compression of the air fuel mix would be difficult.

Hi Paul

What amazes me is that I have no record of anyone owning a Rotamatic.
We're talking about a very big company - Ogden Industries - that sold these
machines for a couple of seasons: yet where are they?

For the record, may I ask how you know your Trojan is off a Rotamatic?
I certainly believe it is; because of the fan above the flywheel.
I suspect Ogden made the fan, and cast the unique alloy cowl.

The Rotamatic, in its Olympic colours, would have looked outright stunning.
A green and gold moon buggy, I guess

All very collectable.
-------------------------------
JACK

Hi Jack, I have the cast cowl which has the fuel tank strap on top and the Ogden logo on the front. Colour looks to be a mustard, may have been gold. I will post up a pic.




Spacers are still present on the mounting bolts to lift the motor up clear of the deck, photos are of as found. You can't see the large scrawled Ogden logo in the pic and it is only barely visible anyway.

Hi Paul

I was wr ... wro... wron... close.
I meant that it was painted with a gloss green enamel base,
with yellow cowl (not gold) and yellow wheels.

Thanks for the photos - first non-factory ones I've seen.
----------------------------------------------------------
JACK

It's a bit cleaner now :-) pity the fuel tank wasn't kept on it.

Just curious on looker...Have you checked the compression? I know borderline minimum compression can give me fits sometimes on 2 cycles here.

Hi AVB,

Found a broken ring and cracked rear seal. Giving it an overhaul now and will see how it goes from a fresh.

Secured the crankshaft seals today, looking for piston rings now. 46 mm bore, 2mm ring. Anyone bought rings for a Trojan/Tor before, mine is 75cc engine with Std piston ?

Ive Not seen New parts for Trojan Paul, I think you'll need to find a collector or club who may have old stock, if no one here has a set.

Ive had success with JP before for impossible pistons and rings, if all else fails check em out. Pretty sure they do A fair bit of Villiers as well....like the 7F.

Send them a sample ring and they may be able to match them.

http://www.jp.com.au/JPPistons.html

Thanks Mal,

On to them and sent a few emails back to the Mother country. 46mm rings are a common size and even the gap profile can be found but 2mm thickness is what I need. Still trimmers use 46mm and there's loads of them, just a bit more digging required.

Lucky the gaskets are only paper type, wonder how thick though ? Corn Flake or Weet Bix type :-)

Rings are sorted, coming from JP Pistons, odd thing with the crankshaft bearings. I have another motor for spares which I stripped down, found that the two cranks use different bearing sizes.

One crank has a 20mm I.D. Bearing either end but the one used on the Ogden mower has a 17mm on the blade end and a 20 mm on the magneto end. Wonder why they went to using a different size bearing on the stressed up end of things. Perhaps this is the reason for the fancy clutch ? Above the blade plate as the crank is thinner down there.

Well done Paul on the Rings Paul, they've helped me a few times.

Not sure on the bearings?

Gasket size Im unsure of. Basic rule for crankcase to barrel is, fit the barrel and measure the distance between barrel end surface and piston to find your thickness,and use the appropriate material allowing a few thou for crush. Crankcase halves are usually dry,sealant or of the thinnest material...eg paper thickness.

As for the head, see if there is any salvageable material to measure,or just run std Victa 125 thickness?

Anyways glad you got your rings, cant wait to see it running:)

Thanks Mal, Bearings are all sorted, crankcase and base gasket are just paper and sealant. The crankcase has an inner lip to seal the halves, very clever. I can salvage the head gasket but I may make a new one. I will put up some pics soon.

A few pics of the progress

First for Jack some better pics of the Ogden cast alloy cowl
Gallery images include:-

Remnants of Ogden logo
Carb side
Underneath
Engine progress
Sealing lip on one side of crankcase
Engine number
Piston
Look what I found
I am hoping it will clean up for a good spare :-)

Hello Paul and ODK Members & Guests

First, thanks to HT6 for recommending JP Pistons.
They appear to be the premier company for sourcing pistons, rings and etc.

Paul, thanks again.
These are invaluable photos in recording this Ogden version of the Trojan 75cc.
The yellow (not gold) cowling would have looked absolutely stunning on this
moon-buggy mower.

This mower was painted in green and yellow for a single purpose: the Melbourne
Olympic Games, in the year this rare mower was introduced. I hope this motor
will mate with a chassis ... some day.

p.s. I love the lipped seal on the crankcase. It was kismet!

All very significant.
---------------------------------
JACK