Saving Old Seagulls

Hi all.
New here, and have what I believe is a relatively early 102 (S/N OP613) which I was given by a neighbour who was sorting through an estate. My nine year old son and I are currently giving it a tidy up. I doubt that it had been run for many years prior to us receiving it, but we set about cleaning out the carb and setting the points. Initially it wouldn’t start with the rope, but a little persuasion from the 18 volt Dewalt and it fired up ok.

I believe the engine is from the late 1930’s, but can anyone shed any more light on its possible ‘pedigree’?

Before starting it I removed the pair of grease nipples on the one side and found a congealed greasy residue. I decided any oil would be better than none so I injected regular motor oil into there until it overflowed (I also hoped that the oil would dilute the grease and help with flush out?’.
There is no plastic cap on the gearbox, just a pair of grease nipples on one side of the lower unit and a single nipple slightly higher on the opposite side. I’ve read through the advice on the SOS website re gear oils but I remain a little confused. I understand that where grease was once recommended it is widely accepted that 140 gear oil is preferred? But how much? I read references suggesting both half full, and full on the website? Do I inject oil into the lower of the nipples until it comes out the top hole?
What about the single grease point on the opposite side? Oil or grease?

Many thanks in advance
Neil.

The local man to talk to for you would be Chris Croul who lives in Beach Haven, not too far for you, his phone number I will PM to you when I've dug it out.
Please don't try to start with the drill again It doesn't do them any good when they're over 80 years old.

Charles

I spoke to Chris who will PM you his phone number, give him a call any evening, looking at your pictures your going to be busy.

Good luck Charles

Nice find! Your OP engine is a fairly rare beast, last of the line of pre-war marston seagulls. I think yours would have been made after the transition to the British Seagull company.
In terms of gearbox lubrication, 140 grade perhaps thickened with some light grease will be fine. These are fairly rare engines, so need to be looked after, avoid use in salt water for example, but if you must, run it in fresh water afterwards to flush through. The ignition coils are a weak spot, but new ones are available in the UK.

The oil that was used in the Wartime & pre War gear boxes was approximately SAE 450 a viscosity that no longer seems to be easily available.

It looks like the prop shaft/bearing is losing quite a lot of lubricant so there could be either badly worn bearings or too thin gearbox lubricant.

With a serial number in the early 600's there is a strong possibility that this one was built in 1936.

For the majority of its life this motors two stroke oil was 30 grade motor oil with a oil mix ratio of 8:1 & without a complete strip down to measure all the bearing clearances it might not be the best idea to go on a cruise to the Bay of Islands carrying an 8 year old.

At over 80 years of age this motor will be in a very fragile state, the gearbox looks tired, the fuel tank will probably have a lot of junk/muck inside & will need a real good clean as will the carb & fuel tap, at 80 years old the ignition probably has a life expectancy that should be measured in minutes not hours!
When you remove the fuel tank to clean, be very gentle with the cylinder as the water jacket outside walls will be surprisingly thin especially if its had any salty use, so plenty penetrating oil a week before if your removing the tank whilst attached to its support bracket as those jubilee clips look well past their best.

Go & see Chris Croul he will talk you through it all.

PS, get yourself the right size spanners, you won't be able to buy those nuts & bolts from Supercheap.

Charles

Thank you all for the responses. Yes, the project will be approached with caution now that I know the significance of what I’ve got.
The jubilee clips holding the tank wound undone surprisingly easily after soaking in CRC overnight. They are now soaking in a parts cleaning / degreasing solution, and will be followed by a bath in rust remover. Similarly, the inside of the tank wasn’t actually too bad; Ive dealt with much worse motor bike and classic car tanks. So, it too had an overnight soaking in cleaner to remove the varnish and muck, and now is being rust treated. Removing the tank bracket from the block is something I am weary of: those four bolts look well stuck?!

I suspect the prop shaft seal has indeed been weeping while it sat idle in someone’s shed for how ever many years? I will disassemble it and check the state of things in due course.

No prop shaft oil seal ,only Bronze bush with the prop shaft through the worn hole in the middle.

Looks like I made a mistake on the date I should have said 37, sorry.

Charles uk wrote: Mon Mar 31, 2025 7:16 pm Looks like I made a mistake on the date I should have said 37, sorry.

Thanks Charles
So as mentioned above, this OP would most likely have had the “British Seagull” flying gull tank transfer, rather than the “Marston Seagull” logo?