[wristpin]

If Meetens can’t help, I believe that Cox and Turner can make them.

Piston Rings

[wristpin]

What a coincidence , I’m just doing a mechanical renovation on a similar UK spec machine that was marketed as a Merry Tiller Titan. Not nearly in as good cosmetic condition as yours. UK spec machines just used a standard SAE 30 or 40 engine oil in the chain case, but as the machines got old and unloved and suffered from leaking rotor shaft oil seals the chain cases were often topped up with semi fluid grease.
Most UK machines had handle bars that could be swung to either the left or right so that the operator was not walking on the freshly turned ground.
The 5hp Briggs on my machine has a 1969 date code.

[wristpin]

You should be able to date the engine by finding the words Model, Type and Code stamped into the engine cowling ( or in Briggs speak the blower housing). The numerals under. Code show the year, month and day of manufacture, so if they start with 55, the engine was made in 1955. If it’s s lot later than the 50s the machine may have been re- engined.
As far as I know the oil in the chain case is checked via a rubber plug or grommet at the top right side of the case. If you want to drain it you will probably have to remove the right hand rotors and turn the machine on it’s side over a suitable tray. May be as well to drain the engine first . If there’s not much oil in the case, start by adding a small quantity and running the machine just to check that there’s not a gross leakage from around the rotor shaft bearings. Dismantling the case to change the bearings and seals is quite a performance, so if there’s a small leak and the machine is not going to get heavy use it could well be advantageous to add semi fluid grease to the case rather than oil.

[wristpin]

I would question the wisdom of setting the points to 16thou, the top end of the recommendation of 12 to 16. I would always aim for the middle of the range as quite often the final tightening of the clamping screw will move them a fraction. If the aiming point was 14thou and they do move, you are still likely to be within range without the need for further fiddling about.

[wristpin]

As ever, start with valves – faces, seats and gaps, then the ignition – points faces and gap, and then the carburettor. No amount of fiddling with the carb will achieve satisfactory running until the basics are right.

[wristpin]

Looks as though it has a JAP engine. Think that I’ve recently seen that another owner is having problems in obtaining a recoil spring. Is it for using or painting and posing?

[wristpin]

A bit more identification information may help e.g. – two or four stroke, plate clutch / cone clutch etc. May even have the original ID tag under a chassis frame bolt head on the RH side plate.Sometimes a round disc and other times like this.

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[wristpin]

That post was mine and referred to a conversion that my late business partner and I did in the early 80s. Having done a straight forward conversion we found the revs somewhat difficult to control. After a bit of head scratching we repurposed the existing points to act as a switch in the feed from the electronic module. The passage of time doesn’t help with remembering exactly What we did but as far as I can remember we considered it to be successful.

[wristpin]

The F15 having been stripped of anything that may be of use it was now the turn of several part stripped JLO L97s and and an electronic ignition RM100 with a rather bent crank. Fortunately JLO used an easily dismantled three piece crank and the lower section was common to a lot of their smaller rotary mower engines, so after a bit of cannibalisation we have a potentially usable short + engine – just need a carb!
The offending lower crank section.

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[wristpin]

Yes, I’ve got a Points F15 on a Ransomes Twenty Four that’s been in the family since new and despite only being started now and again, is always ready to go.
On the subject of Villiers electronic mags and starting I have noticed that the F12s with electronics need a more determined pull than the old points systems that when all else is correct will usually fire on little more than a foot of rope.
Perhaps it’s a characteristic of electronic systems in general, as the Briggs manuals of the day make a point of saying that theirs need x rpm cranking to fire them up . X being more than for the points system – but I’ve forgotten what !!

[wristpin]

From a position of total ignorance of the job in hand I seem to remember the MT accessory sheet showing some dinner plate sized discs called “ crop guards” . Would they have any application in this case ?

[wristpin]

being fitted with the s12 carb would mean it’s a later model , hence 1/8″ timing.

I have a feeling that the plot may get slightly more complicated as one manual with the 1/8″ timing lists a Villiers Junior carb and the other A B10 or Type V.
Is the clue in the OP’s description of the engine being a Mk15HS (High Speed) which none of my manuals cares to mention? Faced with a Mk15 minus its ID plate, what distinguishes it as an HS?

[wristpin]

It may be “process of elimination” check the timing is correct. It’s far better to remove the cylinder head to do this , the points should just begin to crack open at 1/8″ BTDC.

My manuals dated Sept 56 and March 60 say 1/8″ and the ones dated Aug 54 and Jan 55 say 3/16″
Always reassuring !!
They do all agree on the points gap though!

[wristpin]

Being an overhead valve engine it is easy to check the valve gaps, so do that. Then check the plug gap and without removing the flywheel, the points . You then know that three of the possible variables are correct. Should you find that the points are way out they will have affected the timing – slightly – but correcting the setting may just improve things.
With all that lot known to be correct, re- check the carb ; return it to book settings and work from there.
If you are still in trouble you can check the timing without removing the flywheel but it may be easier if you remove the cylinder head – just depend upon the position of the plug hole in relation to the bore for measuring piston position. If with the correct points setting, the timing is way out, it will be necessary to loosen the flywheel – and while you are there remove it and with the improved access give the points a thorough clean.

[wristpin]

I do know that Binks was a carburettor manufacturer. No doubt the pre-war motorbike enthusiasts will tell you that.

Also on my Dennis

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