Stuart Turner 1.5hp - seized

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m1taylor

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Hi,

I have just acquired an unwanted ST 1.5hp R3M. It has not be run for over ten years. Fortunately there are no cracks on the blocks as the water was drained prior to storage. But the engine is seized - as someone who has never taken an engine apart before, any helpful advice would be appreciated. i really want to see if I can unseize it before spending any money on it, so that I can ascertain whether I have a viable poject or not.
 
If you can the head off then pour a load of thin oil onto the piston top and leave it for days or more to allow it to soak through.

Can you access the main bearing etc ?, if so a similar exercise is required.

At the end of all that try a piece off wood on top of the piston follwed by a few sensible taps with a hammer to get things free.

This is not specific to a ST.
 
Is there any movement at all on the flywheel? If there is just a fraction of an inch before it locks up, then the piston has seized (?rusted) in the bore. Pour some diesel through the plug hole and leave it a couple of days before trying to shift it again. Should free off unless badly rusted in which case the bore and piston are not likely to be serviceable anyway.

If there is absolutely no movement in the flywheel, then the crankshaft is seized, and this can be a lot more difficult as there is no direct access to the crankcase. The best bet then is brute force - a hefty socket on the flywheel nut, with a good long extension to give plenty of leverage. If things are not too badly corroded it should shift. Once you have movement, move the piston to the lowest point, then pour around a pint of diesel in and give it a day or two to penetrate thoroughly. If it leaks out from behind the flywheel, then the crankcase seal has gone, and you will never get the engine to start until a new one is fitted!

Make sure the diesel is drained off before trying to start the engine!

Why diesel? It is every bit as effective as any commercial penetrating oil, and a whole lot cheaper in bulk than WD40 or similar!
 
Thanks for that - I think it is a lower end seize, as there is no movement in the flywheel. So I will do as you suggested. And thanks re Diesel - hadn't thought of that! Someone suggested olive oil to me, but that stuck me as rather a waste!
 
Doing a "top end" overhaul on an ST is pretty straightforward. Splitting the crankcase to get at the crankshaft seals is much harder. Lashings of diesel and time, as suggested, will help enormously.

The cylinder casting, cylinder head, exhaust expansion chamber and end casting all have cooling galleries cast into them. They are prone to silting up. Make sure these galleries are clean and free of rust scale. In mine the silt was like concrete and it took me weeks of picking and poking with a wire coathanger to clear them. Even boiling them in water wouldn't soften it!

If the engine has been static for 10 years as you say then the cooling water valves may have seized; either in their guides or 'face to face'. They can be freed easily enough and the faces polished up. Poking a drill bit up the guides and twiddling it with your fingers will shift any salty crud.

The carburettor is very simple; dirt and verdigris can make it sticky so Brasso and elbow grease help here.

FYI. spares, gaskets, etc. are readily available from Fairways Marine; contact details in PBO and CB mags.
IMG_1606.jpg
 
Nice picture!

Takes many of us back a few years. A very tidy Stuart, complete with tramcar gearchange and Stuart seacock. The plug spanner and spare plug stowage is out of shot!
 
Mix 500 cc 10:1 diesel and vinegar+tadge of washing-up liquid -shake well -Remove plug and
pour 100 cc into engine. wait for a couple of days and repeat. Provided there is no
major mechanical damage in engine-ie crank fractured,con rod bent etc-this treatment will ungunge and clean. Drain engine sump . Turn over by hand (repeat
'treatment' if any 'sticky' motion is encountered) Fill with clean oil- replace plug
and engine should run like a 'bought one' (save xcess 300cc mix for seized nuts
bolts )
 
Re: Nice picture!

Mirelle.
Never had the plug out since putting the engine back in the boat last July. Last took her out only a fortnight ago, and the engine starts 3rd or 4th turn of the handle every time.

One other thing. I have seen an installation where the owner had painted the casting underneath the magneto. This needs metal to metal contact, so keep this area clean. A smidgin of oil will keep the rust at bay.
 
Well the thanks to all the good advice, the engine is now freely turning. It was the lower end - loads of oil and and old can of WD40 applied from the top. Then gently, but progressive rocking with a large spanner on the flywheel nut. Gradually the flywheel move a little more, and then I managed to get it turning, and a nice sound of compression in the cylinder. So I may have a viable project! One daft question - I have no starting handle yet - but just how does the starting crank work? It seems just to turn freely and continuously in a clockwise direction, but it doesn't seem to move the flywheel or cause the engine to turn over. Am I missing something, or is there something broken?

Also, do you think I will get away with a top-end de-carb - ie I don't want to have to touch the crankcase. How will I know if I can get away with that?

Thanks in anticipation
 
Theres a ratchet arrangement which should engage the start er mechanism with the flywheel - behind it, where you cant get at it. More freeing oil might get it going. Almost certainly the ratchet tooth has stuck in the up position. Not a problem - if only you can get at it!
 
The ratchets are held in place by two weak springs which may be corroded to nothing. I had a problem with mine where the ratchet teeth were worn round and woudn't engage on the starting wheel sprockets. A bit of welding and half an hour with a file sorted them. I hired a biggish set of pullers to get the flywheel off and get at things and make the painting easier.
 
Re: Nice picture!

Mariposa - just you wait! Re-starting a hot engine is the problem - ST handbook says "fit a new, cold, plug".

It will catch you out when you least expect. I have vivid memories of being sworn at by Germans in Dutch locks!

Cheers,

Mirelle (but was Mytica 2 1/2 tons TM, in those days)
 
Jimminy.
Mine is the P5M with Forward / Neutral / Reverse gearbox on the back. My pic shows the starting chain disappearing between the flywheel and crankcase. I think the R3M has a centrifugal clutch, although the R in the type designation you would expect to mean 'Reverse'.

Mirelle
I have no doubt you are correct. One day, when it is most inconvenient, it will refuse to start, but so far I've been pleasantly surprised. BTW I always stop the engine by shutting off the fuel rather than shorting the magneto. That way you don't end up with either a too rich mix, a gummy carb, or explosive vapour in the bilge.
I've said it before, and I'll say it again, the combination of unleaded fuel and modern 2-stroke oil is like nectar to these machines. If (okay, when) I take the plug out I'll post a pic of it.
2 1/2 TM, correct. Just how I get a tunn of wine through the hatch I haven't figured out, unless I drink it first.
 
Re: Nice picture!

I agree, that picture certainly reminded me of bygone years. I'll probably have to go for more therapy now!
My Stuarts had an inbuilt brain, they would always start and run well UNLESS you really needed them.
I had sailing clutches with no reverse, so Dutch locks were even more fun.
Dan
 
Re: Nice picture!

[ QUOTE ]
I have vivid memories of being sworn at by Germans in Dutch locks!

[/ QUOTE ]

My great-uncle had a similar experience. Mind you, he was at the helm of a converted landing craft which had a bloody great gun poking out the front!
 
Hiya. I stumbled on this as I'm looking at doing up an old R3M myself that I bought with a very exhausted old clinker launch that has been laid up for over 6 years. To my delight, with the attachment of a short fuel line and a new plug cap the engine runs. However the cooling ports are completely sealed with rubbish. I'm therefore hoping to have the top off to clean them out but obviously it's stuck tight. The manual suggests tapping at lugs on the cylinder head with a soft hammer or turning the cylinder bolts a turn and starting her up. The former's not had success yet so I was wondering about soaking the outside in plusgas to try to free it up then having another try. Is the 'blow the top' metho very dangerous or likely to get shards of gunk into the cylinder?

Having read this thread, should i pour some of the diesel / vinegar mixture into the top of the cooling outlet to try to dissolve some of the gunge and hopefully remove some of what's sticking it together? Any recommendations for removing a stuck head from a seawater cooled engine much appreciated.

Many thanks
Ben
 
I've never heard of loosening the cylinder head bolts and starting her up to loosen the head. It might work, but it sounds a bit risky. Have you tried running it until it's hot and then having a go at removing the head with the aid of a hefty mallet? I ended up using a block of hard wood and a lump hammer.

Re-read my previous post on cleaning the cooling galleries. I had no luck at all with chemical cleaning and, IMHO, the only way to confirm the galleries are clear is to poke a wire through them.

Best of luck with your project.
 
I wanted to ask exactly the same question while this threads running.

How do you get the cylinder head off???? I have a P55 6HP 2 cylinger,while on the French canals she blew a head gasket. I couldent move the head. eventualy i towed her to a barge/boat repair shop. They couldent manage either.

We then got a tow to St Jean de Losene where we tried again but try as we may it wouldent move. I paid for a place untill March the following year and zoomed off to buy a diesel engine

With new diesel instaled we took the stuart turner into the workshop and only by useing a wide flat chisels one each side and one each end and with w 5LBS hammer
could we move it

By useing thicker metal wedges we raised the head 2cms or about one inch but there it stayed. we tried hitting it heating it useing a hydralic puller! But it wouldent move.

How is the head supposed to be removed?? Its still in my workshop coverd in oil old cloth and wood shavings!
 
I don't understand. If you raised the head by a couple of cms it IS off.

Look at the picture; 6 bolts, 1 cooling water connection and a spark plug. The cylinder head is just a domed lid sitting on top of the cylinder itself. Okay, it can be a bitch to remove, but once you've broken the joint there's nothing to stop it coming off.
 
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