125/170 Series.

These are scans of original (and rare) brochures and leaflets, they are full of useful information. To keep the loading time to a minimum, I have reproduced them below in a small format. Where text needs to be readable, just click where instructed and you will get a large (readable) version of this area -this will take some time to open.

170/125 SERIES Leaflet

125front  170 small

The model 170 and 125 were a great departure from the traditional ‘British Seagull’ for ‘British Seagull’ and the development of the power head and exhaust led eventually of course to the QB engine.

 The cover did not appeal to all, but the power out put was well in excess of anything ‘British Seagull’ had produced before. (The unit was alleged to produce 7.5 bhp)  The ‘170’ of course was a reference to the pounds thrust at the prop. Add to that the new Forward-Neutral-Reverse gearbox that made this motor so versatile. The engine was fitted with an Amal fuel pump and remote tank.  (Though the tank connectors did not last and now they are replaced with an ‘off the shelf’ connector set, available from most good chandlers.)

 Sadly both models had an ‘Achilles Heel’. 

It was soon found that the con rod and big end cap would easily self-destruct if the engine was over revved. Within a few years ‘Chillington’ had run out of connecting rods, so sadly many otherwise perfect engines were scrapped. I have recently, Sept 2001, heard from a customer that he has had a new con rod made. It is possible that more could be made, so if this is your problem, and you have an otherwise complete 170 or 125 in your shed, speak to me and I’ll follow it up.


Martyn Sandbrook has sent in pics of a new con rod cap he has made from bronze. It is hoped this will cure the problem with his inboard 160. The 160 is the same engine power unit as the 170 and 125. Photos below.

bigend1 small bigend3 small bigend4 small I think you will agree the new one is a bit beefier than the old.!! Martyn is a little concerned about engine balance, he may have to drill the flywheel to counter that. We will see.