Information on Johnson Outboard required

I have just purchased a boat for fishing and it came with a Johnson Outboard.

Serial No: 20BFL78C
Model No: B 3118

I would like to gain further information on the outboard mainly the year, HP and if the engine has an alternator.

Can anyone also tell me where i can puchase a manual for the outboard as i would like to fit an electric start and wire up the alternator if it has one?

I've had a good search for the serial no on the internet but had no luck.

Jamieherd,

20BFL78C is a 20HP 1978. It's a strange model number though and doesn't appear in some of the Johnson model number listings, but it is a valid model number.

It does show up in the 1922-1979 listing of "Recreational" models, so it isn't a commercial or military model.

I can't tell what parts manual covers it. I will be interested to see if anyone can find a parts listing for it.

Little more than a guess.

It is a Belgium made model ? The ID plate should confirm that if it is.

The OP is in the Uk or Ireland ? If so consult a local dealer . Can suggest a couple if in UK.

It is de-rated 25hp model?

An electric start model would almost certainly be fitted with an "alternator" and rectifier but a manual start model probably not.

Look for three yellow wires , one with a blue tracer and one with a gray tracer, coming out from under the flywheel to a terminal strip ... they will be the AC output from the stator coil.
If there is a rectifier, a round thing on a triangular two bolt mounting flange, it will also have three similar yellow wires, also a red wire, connected to corresponding wires on the terminal strip.

(just possible only two yellows )

An electric starter kit and a battery charging kit are both listed as accessories for 1978 25hp models but at well over $400 and over $200 respectively may not be an attractive proposition.

Just thoughts in case useful ... if not ignore!

I had a look at the ID plate and it states the outboard was manufactured in Belgium.

Vics - I am in Fife, Scotland. The outboard is manual start but it is an AC lighting model (So the cover says, it also says it is a 25hp model....), i will follow your guidelines and also have a look to see if it has a regulator/rectifier fitted. If I'm not entirely sure of whats happening or what i'm doing i'll maybe nip it along to these guys http://www.ferrymarine.co.uk/services_outboards.html
Anyone had any dealings with them?

Cheers for the advice.

An AC lighting model won't have a rectifier. The stator output will probably go to a socket. It may be two wire, or 3 wires like the electric start models.

If 2 wire you can use an ordinary bridge rectifier for battery charging but if three wire you need the special one. If it is 3 wire then you could make up a 6 diode rectifier as illustrated in the bottom section of the diagram below.

A battery charging kit may be available but sit down before asking the price!

Good idea to visit your local dealer but in case of difficulty contact OAKLEY MARINE in Brighton

Parts catalogs normally referred to at SHOP.EVINRUDE.COM but your engine is not listed ... not sold in N. America I guess.



Sorry about abbreviated nature of post ... First version vanished without trace when I tried to post it.