Marquis petrol tank

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robint
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Marquis petrol tank

Having followed Chris G's post on his rebuild experiences,  I note the frustration of said petrol tank and its obtuse fixing bolt.  Am I right in assuming the entire fan housing must be removed to access this  bolt?  Its said a special spanner can be used

There is a bit of rust in the bottom of the tank but I cant tell how important this is

Looking at the tank, are the two halves hard soldered together?

Any advice on how to treat the internals and apply a rust proof coating?

 

edit

 

it turns out that removal of the fan cowl is a simple matter of 4 bolts though I am less happy that two of them them are cylinder head bolts.  I might convert these into studs with dome nuts.  Cylinder head bolts into aluminium castings - alarm bells

wristpin
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As long as the rust stays put

As long as the rust stays put it doesn’t do much harm. I clean them by electrolysis but  some people use citric acid. Don’t use “ brick cleaner” or any hydrochloric acid based rust remover as they eat the solder. Tank sealants can have issues of their own.

Tank removal. A flat ( not cranked) ring spanner does the job. If you look right through Chris G’s thread you will find an image that I posted.

Chris G
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Agree that if there is not

Agree that if there is not much rust and it is not loose / flaking - then it shouldn't be an issue, closer inspection will give you a better idea, you will get the tank off, its not that hard with the right spanner and reassembly is much easier.

Hydrochloric... may differ on this one. Yes it eats solder, and rust of course, it also starts to munch steel and will carry on munching if not processed properly. It must be thoroughly cleaned off and neutralised with hot alkaline detergent and only to be used if sealing a tank afterwards as it will flash rust very quickly. But it is quick and highly effective, I've used it many times as prep for POR15 sealing in fuel injected applications which are far more sensitive to rust.

 

 

robint
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Ive used phosphoric acid for

Ive used phosphoric acid for cleaning up superficial rust on old tools, nuts and bolts ect.  Its not too agressive and passivates the rust rather than eating it away to bare metal.  WOW that tank sealant stuff is really expensive, maybe wait till a spare fuel tank comes along.  Will see how the tank is when I get it off. As you say , what numpty designed that?  Then we wondered why the british car industry fell apart - some good Top Gear vids on reasons why - my pet hate was anything British Leyland

Chris G
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EDIT!!!! Everything I wrote

EDIT!!!! Everything I wrote above relates to Phosphoric NOT Hydrochloric !

Phosphoric is in fact the active ingredient in POR's "metal ready"  treatment, thats why I buy it in 5lts at 85% for a fraction of the cost of POR 1ltr metal ready.

The actual POR15 sealer is expensive but done properly you can just forget about it, I have had it in tanks for over 10 years.

Bit gold plated for tiny mower tank tho :-)

robint
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Stand back from success

Stand back from success

I managed to loosen that cursed bolt holding the tank down  more by luck than judgement.  I will be replacing it with a SS socket head bolt.  At least I can chop down an Allen key to suit.  That King Dick spanner shown by WP is as rare as hens teeth

https://www.ebay.co.uk/itm/1-4-UNC-A2-STAINLESS-SOCKET-CAPS-IMPERIAL-HEX...

 

I looked inside the tank and its a bit gungy.  I might put some gravel in it and give it a whirl on my tumbler to lshake up loose stuff

Having removed the engine cowl I now see a flywheel with several fan blades missing.  Maybe look for a spare.  I dont see any "window" for points adjustment. Does this imply it has electronic ignition?  The flywheel is bolt on with a 24mm nut.  I had to send off for a suitable socket for this.  Some have said these are fitted on a taper shaft and perhaps dont have a keyway.  So if I take off this flywheel I may lose my timing.  I would stamp a mark on these items first

 

Or I may just chicken out and leave well enough alone

As they say, if it aint broke, dont fix it

robint
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well I posted some pix and

well I posted some pix and they havent turned up. what have I done wrong?

robint
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I'll try again with just one

I'll try again with just one

 

no that didnt work either

wristpin
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Try this. You can post

Try this. You can post multiple images in one hit.

https://www.oldlawnmowerclub.co.uk/forum/guidelines/adding-images

EDIT

I may have posted an old link,

Try this one

https://www.oldlawnmowerclub.co.uk/forum/adding-images

robint
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so why does it say this?

so why does it say this?

" You are not allowed to post new content in the forum. "

I wasted an hour trying to find a work around and got nowhere. I followed instructions religiously

wristpin
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Looks like I posted an

Looks like I posted an invalid link.

Apologies, try this

https://www.oldlawnmowerclub.co.uk/forum/adding-images

olcadmin
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This looks like the fourth

This looks like the fourth separate thread about the same mower restoration. That makes it difficult (and tedious) for our very conscientious contributors to keep track and provide meaningful replies. Please try and keep discussions about one mower/restoration in a single thread.

OLC Admin

robint
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Another solution, pack the

Another solution, pack the bolt with some washer or a spacer ca 10mm high which will bring the bolt head above the flywheel

As shown there is plenty of clearance to use conventional flat spanners.  PHEW  why didnt some bright apprentice in Ransomes spot that simple trick

 

 

 

NM
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That doesn’t look like a 4”

That doesn’t look like a 4” (100 mm) spacer.

robint
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Sorry I meant 10mm or 1/2". 

Sorry I meant 10mm or 1/2".  Its the sight of that fuel tank that throws me

robint
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I had another light bulb

I had another light bulb moment on how to remove this offending bolt.  Its crude and destructive but if you are stuck...........  Get a tubular spanner 11mm or 7/16" and disc cut off the hexagon part.  you should then fit this over the nut and there should be enough hexagon to use a spanner (17mm) or adjustable to give sufficient purchase.  Its a 1/4" unc/bsw x 3/4" bolt screws into the aluminium crank case. If seized try 24hrs of plus gas.  I always use copper grease when reassembling. It lessens future seizing

 

Failing that means removing the flywheel if you have a 24mm socket handy

wristpin
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Mountains and molehills come

Mountains and molehills come to mind!!!

 

Start the day with a smile and get it over with!

robint
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actually this is a BSA fault,

actually this is a BSA fault, they assemble the tank then put the fly wheel on. apolgies to ransomes apprentices