Hello all, just got my latest aquisition running but can't ID it. It's a standard shaft 102 with clutch and looks like it is older than my other 102's. Model number is DON . 376
Any ideas ?
Regards
Steve
Mystery 102
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
DON is the series code given to ON (1937-1941) motors that originally had a rubber buffer drive but were converted to a spring drive.
The only one of these I've seen had:
A 2 blade prop
The earlier (Marston-type) Amal carb
A steel tiller arm
Steel (unplated) driveshaft tube
Lug on the water pump housing and a bracket on the silencer to fit the accessory aluminium rudder.
Copper magneto cover.
Short water jacket block, with no fins.
It would be interesting to compare, and a photo would be great. Your motor is virtuaqlly a Marston, in fact if it's one of the earlier numbers it actually is a Marston. Sadly I can't tell you what the numbers actually were - but they started with ON 101.
I can't be certain, but I'm fairly sure this one should have a floating gudgeon pin (no circlips), a steel tank with bayonet fitting filler cap, and the earlier cast alloy tank attachment lugs rather than the later pressed steel versions. It should most probably have jubilee clip tank straps rather than the later plated steel ones.
I look forward to hearing more..
These mo
The only one of these I've seen had:
A 2 blade prop
The earlier (Marston-type) Amal carb
A steel tiller arm
Steel (unplated) driveshaft tube
Lug on the water pump housing and a bracket on the silencer to fit the accessory aluminium rudder.
Copper magneto cover.
Short water jacket block, with no fins.
It would be interesting to compare, and a photo would be great. Your motor is virtuaqlly a Marston, in fact if it's one of the earlier numbers it actually is a Marston. Sadly I can't tell you what the numbers actually were - but they started with ON 101.
I can't be certain, but I'm fairly sure this one should have a floating gudgeon pin (no circlips), a steel tank with bayonet fitting filler cap, and the earlier cast alloy tank attachment lugs rather than the later pressed steel versions. It should most probably have jubilee clip tank straps rather than the later plated steel ones.
I look forward to hearing more..
These mo
102
Thanks Charles.
It does have an early Amal complete with a mixing chamber drain cock which I've never seen before. The cylinder has no fins and the tiller is steel. The fuel tank is the same as my other Marston with a central spigot filler cap and attachment brackets brazed on to it. Also the ignition looks the same except the flywheel cover is alloy, although it does have a home made look about it. The flywheel is stamped JM I 420
From the powerhead down everything looks standard 102. The drive tube is plated and the 4 blade prop has 102 cast into it. Also no sign of any fixings for a rudder.
Could this be an early powerhead fitted to a later 102 leg ?
If anyone could advise me how, I will post some pics.
Regards
Steve
It does have an early Amal complete with a mixing chamber drain cock which I've never seen before. The cylinder has no fins and the tiller is steel. The fuel tank is the same as my other Marston with a central spigot filler cap and attachment brackets brazed on to it. Also the ignition looks the same except the flywheel cover is alloy, although it does have a home made look about it. The flywheel is stamped JM I 420
From the powerhead down everything looks standard 102. The drive tube is plated and the 4 blade prop has 102 cast into it. Also no sign of any fixings for a rudder.
Could this be an early powerhead fitted to a later 102 leg ?
If anyone could advise me how, I will post some pics.
Regards
Steve
I think the best bet would be to mail some to John, who'll put 'em up on the site, or indeed to our web master who is a most helpful chap.
I'm puzzled by the 'fins or no fins' question, and have been feverishly corresponding with others who have infinitely more knowledge than myself.
It appears that the presence or absence of cooling fins on most of the early models (78cc Teardrop, 102cc teardrop, and 102cc short water jacket blocks) is something of a lottery. It would be wonderful to think that Marston's and British Seagull chose to equip motors destined for warmer climes with fins, and those for more temperate regions with none, but I rather doubt it. It's more probable that they just built the things with whichever block was next on the shelf. Further reearch may reveal more.
I rather think that your motor is 'as built'.
Do you have a serial code and number on the crankcase? Is the tank decal present?
I'm puzzled by the 'fins or no fins' question, and have been feverishly corresponding with others who have infinitely more knowledge than myself.
It appears that the presence or absence of cooling fins on most of the early models (78cc Teardrop, 102cc teardrop, and 102cc short water jacket blocks) is something of a lottery. It would be wonderful to think that Marston's and British Seagull chose to equip motors destined for warmer climes with fins, and those for more temperate regions with none, but I rather doubt it. It's more probable that they just built the things with whichever block was next on the shelf. Further reearch may reveal more.
I rather think that your motor is 'as built'.
Do you have a serial code and number on the crankcase? Is the tank decal present?
102
The only markings on the crankcase are the DON . 376 in the usual seagull location and the tank has been hand painted so any decals can't be seen. The tank has brought up another mystery because as I've stripped the engine today I've found that it is only held on with 2 bolts, instead of 4, because the tank mounting bracket holes don't line up with the cylinder holes. Regular 102 brackets do line up however....
Another question if I may, what type of throttle lever should this motor have ? The one fitted has no ID markings and looks more likely to have come from a lawnmower or something. I have some old Villiers levers so if they are suitable one shall be fitted.
I've mailed a pic to John so hopefully he'll be able to post it
Another question if I may, what type of throttle lever should this motor have ? The one fitted has no ID markings and looks more likely to have come from a lawnmower or something. I have some old Villiers levers so if they are suitable one shall be fitted.
I've mailed a pic to John so hopefully he'll be able to post it
I think I will use a Villiers in that case, as it is much better looking than the contraption that came with it. The stripdown was successful and the only nasty find was that the cylinder waterways were a bit clogged with rust. The cylinder is now soaking in a bucket of diesel which will hopefully soften it up a bit. Reassembly was completed using a finned cylinder which was in my workshop awaiting a new home. I wondered if this might be a bit sacreligious but in your earlier posting you mentioned that they are common to these models. Anyway, she now runs very sweetly so thanks for all your advice.
Regards,
Steve
Regards,
Steve