LS carb
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LS carb
Having not had an LS before, was wondering if the FP carb is exactly the same or at least an easy fit. According to the service sheet I have[ from the late 70s?] cylinders and crankcases as well as gaskets are unavailable other parts must be scarce as well. Can a later head gasket be modified to fit?
An LS is quite a rare bird, and not many survive. It was really the second attempt at a small motor, following as it did the successful but short lived 'Lttle Model Forty', the FV and its larger brother the FVP.
The LS shared the same power head construction with the FV series, relying on bolts that passed right the way through the water jacket from the crankcase to the cylinder head, with steel gaskets either end. With many salt water motors this resulted in a lot of corrosion, with large lumps of aluminium disappearing from both ends. The original steel gaskets are unobtainable, but the surviving bits of the old ones may serve as a template. I have heard of people using the copper ones from later models, but I'm not sure how successful that was. I suspect that if the hgoles are in the right place it may be worth a try.
The original early fifties technical sheet referring to these motors emphasised the need for copious amounts of compound to seal the various bits tight. It was a black bituminous sticky product that cured into a quite hard lump. It's probable that sufficient of some similar gasket-goo could reinforce an eaten away steel head gasket well enough to function.
Therer's a picture on the main site of an 'exploded' FV which is identical in layout, can't find it at the moment.
Thew crankcase differs from the later Forty series in the attachment of the drive shaft casing, which is inserted into the crankcase base and secured by a clench bolt. Dismantling these motors can be a challenge!
Good luck
The LS shared the same power head construction with the FV series, relying on bolts that passed right the way through the water jacket from the crankcase to the cylinder head, with steel gaskets either end. With many salt water motors this resulted in a lot of corrosion, with large lumps of aluminium disappearing from both ends. The original steel gaskets are unobtainable, but the surviving bits of the old ones may serve as a template. I have heard of people using the copper ones from later models, but I'm not sure how successful that was. I suspect that if the hgoles are in the right place it may be worth a try.
The original early fifties technical sheet referring to these motors emphasised the need for copious amounts of compound to seal the various bits tight. It was a black bituminous sticky product that cured into a quite hard lump. It's probable that sufficient of some similar gasket-goo could reinforce an eaten away steel head gasket well enough to function.
Therer's a picture on the main site of an 'exploded' FV which is identical in layout, can't find it at the moment.
Thew crankcase differs from the later Forty series in the attachment of the drive shaft casing, which is inserted into the crankcase base and secured by a clench bolt. Dismantling these motors can be a challenge!
Good luck
I've got one of these under restoration at the moment.
It all came apart fairly easily, with only one head stud shearing in the crankcase, which has since been successfully drilled out without butchering the thread.
A previous owner appears to have replaced the head and base gaskets with home made, which would be OK if he'd got the stud holes in the right place.
Head and crankcase do have significant erosion around the studs but the block is perfect. The bore and piston show little sign of actual work and the crank appears perfect. There are a few rust pits in the gudgeon pin, so I intend to replace that.
New head and base gaskets have been made, using 1.5 mm steel sheet, surface ground flat at the college machine shop I used to attend and with central hole bored to diameter. Stud holes in the right places this time.
I've made up 316 stainless studs for it, on the basis that, for a relatively low stressed engine, corrosion resistance is more useful than ultimate strength. I still need to order other stainless hardware.
The flywheel mag appeared to have a good spark (ouch), but the carb needed a dunking in my old deep fat fryer full of hydraulic oil to get it apart. I'm not sure whether it's viable to repair yet.
I've decided against dismantling the gearbox and will be satisfied with a new water pump impeller at the bottom end.
Overall, it seems like a nicely designed little engine. I look forward to getting it back together and running it.
It all came apart fairly easily, with only one head stud shearing in the crankcase, which has since been successfully drilled out without butchering the thread.
A previous owner appears to have replaced the head and base gaskets with home made, which would be OK if he'd got the stud holes in the right place.
Head and crankcase do have significant erosion around the studs but the block is perfect. The bore and piston show little sign of actual work and the crank appears perfect. There are a few rust pits in the gudgeon pin, so I intend to replace that.
New head and base gaskets have been made, using 1.5 mm steel sheet, surface ground flat at the college machine shop I used to attend and with central hole bored to diameter. Stud holes in the right places this time.
I've made up 316 stainless studs for it, on the basis that, for a relatively low stressed engine, corrosion resistance is more useful than ultimate strength. I still need to order other stainless hardware.
The flywheel mag appeared to have a good spark (ouch), but the carb needed a dunking in my old deep fat fryer full of hydraulic oil to get it apart. I'm not sure whether it's viable to repair yet.
I've decided against dismantling the gearbox and will be satisfied with a new water pump impeller at the bottom end.
Overall, it seems like a nicely designed little engine. I look forward to getting it back together and running it.