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Collection, Preservation and Display of Old Lawn Mowers

Ransomes Marquis Mk4 - in need of re-animation

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My 17" super colt (I think - perhaps super punch - anyway 98G14 engine) was a bit reluctant to start this season, so the obvious answer was to buy another completely non-working Marquis Mk4 20"  (serial number DE716) ......which somehow feels like buying a jag as an upgrade to a cortina but perhaps I am being disloyal to Suffolk.

I think it has been 'stored outside' for a few years, but the engine turns over and it's basically complete.  There is so much greasy grime on it that a lot of it seems in good condition underneath - obviously the exposed paintwork is a bit rough.  One of the main rollers seems jammed, the other spins freely.  There are only two front wooden rollers left and no grass box - which i have no doubt will cost me at least 5 times what the mower cost,  but I think that stage is a long way off yet. 

I was hoping for one of those 'despite being immersed in a bog for three decades, a splosh of fresh fuel, and  a light going over with a feather duster and she started on the second pull' type of anecdotes.  Unfortunately that is not the case.

I have a  couple of questions:

1) There is no sign of a spark at all, despite vigorous pulls- either across spark gap or from end of HT lead.   I saw a reference in another thread to a 'window' through the flywheel, but I cannot see it.  Is the next stage to take off the flywheel and get at the points (or electronic ignition?) or are there other things I can try to do first?   (I am desperately trying to avoid my 9 year old boy instinct to just take stuff apart willy nilly and end up with a pile of bits)

2) There is a sort of bracket thing on the back of the engine shroud that looks as if it may be meant to hold a spring, and perhaps rotate - is it some kind of choke mechanism?

3) Is the big disk a centrifugal clutch ?- if so it appears to be jammed as it always turns the drive shaft even when rotated slowly by hand.

In the meantime I will shove a scope camera down the plug hole and see if I can see the state of the inside of the cylinder, and drain the oil and refill it.  I have squirted every visible nut and bolt with penetrating oil.  I am considering buying an ultrasonic cleaner to clean the carb (and the zenith off the suffolk).

Thanks in advance - I know the depth of expertise to be found on this forum, and the willingness with which it is shared - I was last here asking questions about a kick start 2 stroke late 1950s Atco, in about 2009..... in the end I had to sell it - it was like driving a tank around a small lawn - noise, smell and fear.

 

 

 

Forums

wristpin Tue, 07/05/2019

Never mind pics down the bore, let's have some general ones of the machine to aid identification of the "sort of bracket" and even what engine you have. If theres no window in the flywheel, I'm guessing a Briggs and Stratton. Stamped into the blower housing (engine shroud) will be the words Model, Type and Code. The numbers under those words will tell a story but for now if the first two digits of the number under Code are 80 or later, your engine should have electronic ignition and theres no need to pull the flywheel.

Let's  have those images

 

MattD Tue, 07/05/2019

Its definitely a BSA sloper ..hence why I was mad enough to buy it -- I will take some closer pics in the daylight but these are the ones I have at the moment

And the plug hole is not over the piston bore, so I could only just see the very edge of the piston anyway !

wristpin Tue, 07/05/2019

OK, but a Sloper flywheel should have a window. See below, covered with a steel plate secured with a screw. Behind the flywheel will be a coil, condenser and contact breaker set and as the machine has spent time in inhospitable conditions it will make life easier if  it is removed to give decent access for a proper examination and clean up. Don't be tempted to use a legged puller around the outer circumference of the flywheel  and don't use the fins to hold it.

You will need to acquire or make a puller to pick up on the three UNC tapped holes provided for pulling near to the flywheel's centre boss. Do not be tempted to lever against the rim and bash the crank to jar it off .

Hopefully a good clean up of the points will find a spark  - 18 thou gap. - but be prepared for a bad condenser as they tend to suffer from damp and time ; more so than the coils.

You can convert to electronic ignition  - retain the coil and replace the condenser and points  with a module such as a Meco or Nova. The Meco, in particular will fit inside the magneto  but either may be installed outside while leaving the points and condenser  disconnected but in place.

 

 

 

MattD Fri, 10/05/2019

Wristpin - thanks for the suggestions so far.

I have a puller - but not right size bolts for the holes in the flywheel - any idea what the thread is?  And where do you go to get imperial bolts nowadays?   I could tap it out to an M size but that may go wrong.

I did find the window when I looked in daylight - whats behind it looks surprisingly new and clean, - points and condenser -  but the contact points are not closing at all, which I assume will prevent any kind of spark - I've slackened off the retaining screw but I cant see how to close them.  If I remember correctly in a car distributor there was a slot you put a screwdriver in an levered the whole points backplate around to adjust its position relative to the moving arm.

Of course getting the flywheel off would help as I could see the whole thing!

The oil that came out had the consistency of phlegm......i will put new in and flush it out and replace again after I have got the engine running.

Ultrasonic cleaner for the carb arrives tomorrow - looking forward to some weekend fun.

Matt

 

wristpin Fri, 10/05/2019

Puller threads. As per my post, UNC (Unified Coarse) which can be a bit of a problem as nearly all the “ high street “ Ironmongers / diy multiples only stock metric these days. Try an agricultural merchant or an online specialist such as Namrik .  I would advise against re-tapping oversize metric .

https://www.namrick.co.uk/acatalog/Home_U_N_C_Bolts___Nuts__7.html

Points. The cause of  your  problem in achieving the correct gap may be that the moving point is seized on its pivot. Again, easier to deal with without the flywheel.

MattD Sat, 11/05/2019

Flywheel puller threads seemed to be 1/4UNC based on the locating screw - got some bolts from a traditional motoring store - one of the threads was a bit oddly angled but it worked fine.

I have a spark!  - I felt it before I saw it.  I took the points and condenser out, cleaned all the contacts and put them back - with an 18thou gap and oiled the felt pad.  I removed the plug connector and re-screwed it onto the lead and cleaned the brass plug gripper.   The flywheel magnet seemed a bit weak, which worried me but I can now see a spark across the plug gap (rather than up my finger) so it is all working.

The fuel pipe has fallen apart so will need to be replaced.   I am wondering whether to take the carb apart and clean it - or see what I can make happen in its current state without messing any settings or jets about.

I guess I need to look at freeing the centrifugal clutch and unseizing the rear roller as well.  Is the clutch accessible without removing the engine?

Matt

wristpin Sat, 11/05/2019

It is possible to slide the drum up the top shaft to access the shoes, but I usually remove the engine. To move the drum you will need to release the grub screw in its boss, open the limiting circlip and slide it away to give more access and probably clean the paint off the shaft.

Freeing the roller can be a bit of a saga. First remember that they are cast iron and quite brittle. To get the roller out of the chassis the drive sprocket has to be unscrewed, left hand thread and probably ** tight. You will need to make a tool or use a chain wrench  to grip the sprocket. At the other end the shaft has a slot in it . Again, a suitable tool is needed to grip it . I usually do the job with the engine off, the machine on the bench and tipped back so that the handle bars provide a reaction to the clockwise turning force needed to undo the sprocket.

 

 

 

will 

MattD Sun, 12/05/2019

Today was not a good day - in attempting to remove the grub screw on the clutch I was worried that I was rounding it off with the allen key - so I shoved in a torx bit which seemed a lot better fit - and then promptly ripped the end off it - leaving the remains firmly embedded inside the grub screw.

I had used penetrating oil and left it for hours and heat from a blowtorch, at least twice over before resorting to the torx bit - but all to no avail.

I've since blunted about 4 cobalt drill bits attempting to drill it out and have managed to get about 1.5mm into the top.  The torx bit was certainly pretty hard steel - if not strong enough.

The engine is still resolutely attached to the clutch!

I have managed to clean out and de-rust the fuel tank - and just about got the stuck roller moving.  I put the engine bolts into my ultrasonic cleaner and they are now super clean.  So there was some progress but not a lot.

MattD Wed, 15/05/2019

I've googled DIY spark eroder already....   I think paying to get it fixed may make the whole mower fall into the 'economically unviable' category .  I will continue to drill away at the grub screw/broken bit from time to time and perhaps in the end patience will pay off.

Should the two sides of the clutch come apart anyway?  From the parts diagram it looks like there is a bearing between the two halves - is there any kind of clip holding the two sides in place?   I cant work out if it's just seized shoes jamming it or something more structural and I don't want to do any more damage.

With the engine off the chassis I could at least concentrate on getting that running.

Thanks

Matt

 

 

hortimech Wed, 15/05/2019

Yes, the clutch should come apart and fairly easily. The easiest way is to unbolt the engine and pull it away from the clutch bell housing/shaft, though you might have to give it a sharp tug. You will still have to get the drum removed, but you will be able to remove the entire shaft to work on it.

wristpin Thu, 16/05/2019

As per Hortimech's answer but the "quite easily" bit is a mite optimistic from recent experience .  The top shaft that carries the drum extends into the centre of the clutch flywheel that carries the shoes where it is supported by a self-aligning bearing. The fit between shaft and bearing can be extremely tight and sometimes the bearing pulls out of the flywheel and remains on the shaft where it can be removed with a normal two or three leg puller. I had one recently where the only way to separate the engine from the top shaft was to simultaneously hit both exposed sides of the flywheel with two heavy copper hammers.

Removing the seized clutch shoes from their pins was not a lot easier and they left their bushes seized to their pivot pins .

Before I reassemble one as tight as the above I carefully file a small chamfered lead onto the end of the top shaft and polish up the shaft with fine emery cloth tape to ease its entry back into the bearing . Being able to slide the drum away from the clutch body allows "sighting" the shaft into the bearing.

When reassembling the shoes onto the flywheel note that the pivoted ends lead . Fitting them with the free ends leading results in a very snatchy clutch

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