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Boat Repair/seagull outboard motor


Zimmerman wrote at 2006-06-18 22:13:28
British Seagulls fall into 2 categories. The earlier ones run with a 10:1 mixture, but later ones (including ones with Bing Carbs)run with 25:1 mixture. There is a conversion kit.

Antares wrote at 2006-07-29 12:35:39
I have 3 different british seagull outboards and they all use 1 to 10 oil to fuel mix, a little smoky but they will last forever.

Tom wrote at 2006-08-02 14:55:50
Just a note on the ratio oil to petro on the british seagull outboard.  Pre January 1978 models require a 10:1 perto/oil ratio.  Models manufactured after Jan 1978 require a 25:1 ratio.

foonman wrote at 2006-08-13 20:48:43
from (another) website, 10:1 from 1931 engines to 1978 engines, And 25:1 from 1978 to present. The rod bearing on some older engines appears to be machined from the aluminium of the connecting rod, on later engines PROBABLY a roller bearing.

RedSkywalker wrote at 2006-09-22 20:08:52
The vast majority of Seagull outboards are set for a 25 to 1 ratio but there is a conversion needle available to change them to 10 to 1.

Forrest wrote at 2006-10-14 01:45:54
(I have a British seagull  outboard motor (5 hp). The correct oil/gas ratio is 1 to 10.  

Seqgull guy wrote at 2007-04-07 00:01:20
Go to British for the info you want.  Seagull outboards used either 10:1 or 25:1 depending on the model.  

MIKE wrote at 2008-09-29 04:38:33

whezznor wrote at 2008-10-13 17:18:10
10 to 1 on pre 1978 motors, 25 to 1 to present. Seems like a lot of oil but seagulls have different bearings than other 2 strokes. Anything less will kill them quick. Also some 1968 to 1978 can be converted to run on 25 to 1.

Seagull sam wrote at 2009-08-27 18:30:15
Absolute rubbish, follow this advice and you will wreck your engine within minutes. According to the year of manufacture, Seagull outboards run on either a 10-1 or 25-1 petrol/oil mix. E-mail Seagull with your engine number and they will confirm the mix for you.

Johan Galea wrote at 2009-12-07 09:47:06
Seagull outboards are either 1:10 oil ratio or 1:25 .The modern ones which were specified as 1:50 disintegrate if used so and i reccomend 1:25 anyway.

The seagull normally has the oil ratio embossed on the fuel cap .

normally you can judge by the fuel tank if it is brass 1:10 if it is iron or plastic 1:25 (the only way to know for sure is by dismantling the villiers carb and cheking what needle size it has if 3 stamped on it it's 1:10  if it has a 2 it's 1:25)

Reg wrote at 2015-11-25 13:56:30
Seagull outboards are simple 3 port deflector piston engines with low compression ratio. In line with their age they are specified to use 10:1 fuel:oil ratio. However it is ok now to use 25:1 and needles + jets are readily available.

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C. Thomas Hunter


I am a certified and active Coast Guard Auxiliary Coxswain and instructor. I teach a course in boating maintenance for Pronce George`s Community College in Maryland. I have a broad range of experience in boat operation, maintenance and repair. I currently own a 25 year old power boat that many have thought is new. I rebuilt and restored this vessel from the keil up. I will be happy to be of service to any of your folks that migh need help. If I can help, I will. If I can`t help, I will say so.


50 years of boating in both sail and power.
5 years in Coast Guard Auxiliary operations and education.
Boat owner with a limited budget.

U.S. Coast Guard Auxiliary
Prince Geroge's Community College instructor in boating maintenance, boating safety, and navigation.

Bachelor's degrees in Mechanical Engineering, Electrical Engineering and Physics.

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