[vhgmcbuddy]

Hi all, we currently have 150 machines booked in for tractorfest, looking like another great line up, looking for more howard machines, so if you have one and would like to exhibit please drop me a line and we can get some forms out to you

[vhgmcbuddy]

Ransomes MG crawler. When I was a child, I had a cut away drawing of one showing all the different parts. It always fascinated me and have wanted one ever since. I am pretty sure I still have the drawing somewhere!!

Like yourself, my Dad is to blame for my garden machinery collection. He had always grown his own fruit and veg (and still does even in his 8th decade!!), so once a year the Trusty was dragged out of hibernation and used to plough the garden. A Howard 400 was then used to break the soil down.
I was never really interested in the stuff until 7 years ago, when I was made redundant from my then job. Finding myself at a bit of a loose end, I dragged one of his abandoned Trusty’s from the nettle patch and started tinkering, and have never stopped!!

Sean

[vhgmcbuddy]

Here are photos of one of my two, both identical. Are probably a later model as both the cutter bar and wheel are chain driven.

Attachments:

1. 
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[vhgmcbuddy]

jap two stroke engines manual ordered

[vhgmcbuddy]

Sure I have 2 brand new tubes if you need them. Guessing you will as most of the time you will destroy the old ones getting them out!!

Where are you based? I am in West Sussex if you get stuck

[vhgmcbuddy]

so I guess the 40 on the end indicates type 40, I have looked up the G and this indicates 1959

[vhgmcbuddy]

thankyou for the replies I have found the engine number – s80’G’14957’40

[vhgmcbuddy]

I believe it is a jap 80cc

[vhgmcbuddy]

Chris,

Thank you too; all good info!

Tony

[vhgmcbuddy]

Ted,

Many thanks; will give it a go!

Tony

[vhgmcbuddy]

Andy, in the manual posted by Charlie and Rod, it states rotate the engine back from TDC by 38 degrees. If the engine has a stroke of 104mm for 180 degrees of crank rotation, 38 degrees works out at 22mm down the bore, not far off an inch, which agreed sounds way too advanced. Maybe a mistake in the manual??

Sorry Tim, can’t help identifying the engine from the numbers you posted. Maybe post a photo or two so we can be sure we are all talking about the same model of engine?

Sean

[vhgmcbuddy]

Ah! Thanks Busman – seeing as the head comes off so easily i was thinking there has to be a simpler/more accurate way to get the points opening at the right point of compression than dicking about trying to measure degrees of rotation etc – it would be far more accurate to simply take of the head, measure down the bore that specific distance to the point of optimum compression and set the spark to come then.

As it is – having measured it by 38degrees rotation from TDC by my method described above, the cylinder is a good inch or so down the bore and this seemed too great a distance – not actually achieving a decent level of compression. Now your manual talks about 1/4″ I’m even more suspicious that what i’ve set it to can’t be right….

How can i tell what model of engine it is? The number 81020/4 is stamped on the engine cowl, but there is nothing stamped on the brass plate riveted to the “stone flap” at the back of the machine, it’s just blank…

My engine has a solid copper head gasket on which i was advised to simply heat to cherry-red with a blow torch, quench, then install -thereby “annealing” it – which I didn’t do as i didnt have a blow torch down the allotment…i just put it back together – it’s dry, no gasket sealant and didnt seem to be before either….

At the moment, there’s no spark so i’m going to try and sort that out – if i get it sparking I’ll give it a go as it is (set at 38degrees back from TDC) and if that’s really ropey then will re-do it 1/4″ down the bore….

It must just be me but i am sure the manual could have been written in a more straightforward manner.

[vhgmcbuddy]

Just to confuse matters, the manual I have differs from what has already been provided by Charlie and Rod, stating that the points should commence to open 1/4″ before top dead centre. Don’t know how many versions of JAP engine were available for the Gem and if my manual applies to your engine.

Attachments:

1. JAP-600-Mk-III-Type-5-Timing.pdf

[vhgmcbuddy]

Made some progress i think…

Took the cover off to the chain drive between crank / magneto and was able to take off the crank sprocket/chain. Made a little plastic indicator out of a plant label fixed to the crankshaft with the nut, and then turned the starting handle to rotate the engine through the compression stroke to TDC, and then wound it back 38degrees.

This translated as about an inch in travel down the bore – does that sound about right?

I then rotated the mag shaft until the points were just starting to open.

Put it all back together.

whizz the handle…

No spark at the mag…. the cap doesnt have a screw to hold the HT lead in place, i think it must be a push-fit, but as the HT lead itself doesnt have a brass ferrule crimped to it, it was just held in place with masking tape – so i think that needs some attention first, but with the amount of cable exposed and pushed into the mag cap it should still have been okay.

I’ll get a little wet-n-dry paper and try and clean up the points, and may as well get a new spark-plug too…

then take it from there…

[vhgmcbuddy]

good move,
read as much as you can.
you are asking the right questions, it will work well when fixed.

whole book, there several editions.
https://www.dropbox.com/s/8lnthdz07lflmz1/Engine%20Gem%20JAP%20600cc%20MK%20II%20Engine_Instruction%20%26%20Parts%20List.pdf?dl=0

serial number as stamped into top of main frame pipe is how to date.
should be on the brass plate on rotor cover too.
then see howardgem.webs for approximate date, see where it fits in the list there.
post sn here with a pic or 2?

cheers Rod.

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