Ransome Mastiff 30”

[burls]

Gidday all from down under

I have acquired a Mastiff30” to start rejuvenating my lawn (yep it’s big).
(MAG engine not battery model)
Unfortunately it’s not running atm. So far l have been unable to get spark. I have taken the mag off and had a bit of a look – all looks ok except for slight rub mark on HT coil.
My first question is l have 4 wires coming from the coils, Yellow, Yellow Black from LT coil, Brown from earth point on plate and Black from the condenser. Where/how should these be routed

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[wristpin]

You don’t identify the engine – SRL xxx ? However back in the day many of the MAGs fitted to Mastiffs etc were equipped for electric start or lighting even though that wasn’t fitted. So, as you say coils – in the plural, you probably have a surplus charging coil.
Identify the ignition coil with the HT plug lead and probably a single primary coil wire going to the points where it will probably share a common terminal with the condenser / capacitor and maybe a kill wire going to an on/off switch on the handle bar. Memory says that the internal wires are often taken to a terminal block on the outside of the engine cowling.
If it will help, I can possibly find a wiring diagram but it will assist if you can supply the SRL number.

[burls]

Gidday mate, thanks for your input

Reg’d No DW 02348

Makes sense its a charge coil, l thought it must have been a trigger coil. With this new info, l will check points work correctly. I do suspect the spark coil has failed though.

Photo of coil plate for review

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[burls]

Update, l have spark

There was no continuity between points so gave them a good talking to and fixed that, set the points gap to 0.016” and now l have spark. Next is to clean the carby (it’s a mess)

[wristpin]

16 thou is correct but it was always important to make sure that the the points faces were flat and square to each other for a setting that would “last the season”. I remember having to go out to Mastiffs that had lost their spark mid season .
Bad news that the carb is in a mess. Hope that it’s not too worn and drawing air around the spindle.
A problem with old Mag engined Mastiffs was to get them to idle ( tick over) low enough to disengage the centrifugal clutch to allow clean engagement of the gears. The original Mastiffs had a slow revving JAP engine and a MAG in good condition was just about slow enough but needed to be “ about spot on” to disengage the clutch and then not bog down when the throttle was called on to move off. A Kohler conversion sold by the then UK Kohler distributor was never happy – just would not idle slow enough. So let’s hope that you can sort the carb; may be worth giving the lump a valve job while you’re about it.
I can’t vouch for it, but something tells me that Ransomes offered a set of stronger springs for the clutch – but it was a while ago !
Let us know how you get on!

[burls]

Carby is in soaking now, lve managed to get it all apart except for the tiny brass screw in the base next to the main jet standoff. All is very tight so hope no leakages. The needle was stuck in the seat, l got it out and hope it cleans up and seals. I looked around for kits but no success.
The carby housing has number SC16 838E.5/50 stamped on it

[davidbliss]

I have been restoring engines in size from small to large, the older bronze carbs are slightly easier as can heat parts but the die-cast monkey metal ones can be very delicate and more care is needed to get stubborn screws and jets out, many years ago just by accident after washing my hands left a real badly petrol varnish encrusted carburettor in the washing bowl full of hot soapy water, just thinking it might help clean some of the rubbish off the outside. Well it made a tremendous difference most of the brown varnish like deposits left by the petrol had gone whitish and blew away with the air line, even some of the jets just unscrewed easily, so out with a saucepan added a table spoon of washing powder and boiled it for several minutes and left it soaking overnight it was like magic, even managed to clear those very very small cross drillings into the Venturi that some small product carbs have, I had one carburettor brought to me looking like new but wouldn’t idle, I just guessed a long drilling might be blocked, bit of WD 40 or washing up liquid over one end and bit of air in the other and no bubbles and boiling it worked as so easy. Now a word of warning, a DO NOT DO and many people would have said and seen this coming, I would often put a float into hot water to find pin-hole leaks as hot air expands, solder up hole, if it hadn’t got one its important to drill a very small hole and let the float cool and then solder that up and check again. This particular time water must have been near to boiling and just dropped it in and poked it under, I had not checked carefully enough as must have had some bit of petrol in and a minutest hole as instantly it went off pop and took some time teasing it back into shape. Just recently started to rebuild a very early Zenith as jets were so badly damaged had to mill part of them away and make new with screw cut threads as a odd (French?)pitch, one blanking plug had less than three threads. As for good idling I like Zenith and fit those, and can still can get some new, like the 24 T that fitted tractors, Villiers and Petters even the little J.A.P water pumps we still have two in use from the 40s and replaced the old carbs with new 40 odd years ago 13 T CA-2 identical but now I find the petrol pipes are push on. Meetings in London still had parts for the J.A.P and Villiers.

• This reply was modified 2 years, 1 month ago by davidbliss.

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[andyfrost]

Always check floats in COLD water , as much as I hate the modern world , ultrasonic cleaners are the way to go , they will clear carbs that no amount of compressed air will ever do.
Meetens are sadly no longer with us , Paul Childs(the leading man on Villiers/JAP on this planet) sold the buisness quite some time ago , L&S engineers bought the remaining stock , but sadly lack Pauls knowledge and expertise.

Andy.

[burls]

Cleaned the carby best I could but still think it is the fault. I cant get it to idle and the governor keep hunting. Any thoughts on where or what carby replacement I can get/use?

[Author]

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