Yamaha 5 BS air-cooled

[JBf]

Hi everyone.
I recently got two of these engines, one Yamaha and one Mariner twin.
My problem is that I can't get any documentation for them.
I looked across the internet for a repair manual, to no avail.
Could one of you help me out?

Best regards Jim

 

[ash2020]

1. Parts List (1976+)​

A comprehensive parts catalog that’s ideal for identifying and ordering replacements:

• Yamaha 5BS‑661 Parts List (from 1976 onwards) – includes exploded diagrams and part numbers scribd.com+11gjoel-marinecenter.dk+11boatdesign.net+11.

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2. DIY Maintenance & Repair Guide​

Although not officially Yamaha-sourced, this PDF offers step-by-step instructions, specs, photos, and troubleshooting tips tailored to the 5BS‑661:

• “How to Maintain and Repair a Yamaha 5BS 661 Outboard Motor” – covers fuel system, cooling, lubrication, prop shaft, and ignition issues simcarabinieri.it.

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🛠 3. Full Service Manual (Paid PDF)​

For a complete official service manual (95 pages, multi-language) including wiring diagrams, tools list, procedures, and exploded views:

• “Yamaha 5B & 5BS Service Manual PDF”, available for purchase (~€14.99) from a European marine parts webshop nionwatersport-webshop.nl.

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4. General 103 cc Two-Stroke Manual​

This is a generic service manual for a 5 hp, 1-cylinder, 103 cc 2‑stroke Yamaha outboard (approx. 1984). Good for mechanical reference if you can’t find the exact model PDF gjoel-marinecenter.dk+11slideshare.net+11simcarabinieri.it+11.

 

[Refueler]

Years ago - I had two of the Yam 5BS engines ..... I liked them ... being air-cooled were slightly lighter than the water-cooled version.

One point to note - being Air Cooled - they run a little hotter than the water cooled ... and I was advised to use 2T oil for Air Cooled engines as in garden gear etc - not the lower temp rated for water cooled. Never had a manual - so just trusted the Outboard service guy advice.

 

[JBf]

Thanks a lot, guys.

This link was with a virus, though: simcarabinieri.it.

It will be my backup motor. I like its light, and it has no impeller to worry about.
I will mainly lie around beneath the deck but of course it has to be serviced and ready to go should my main engine go crap.
The main engine will most likely be a tuned-up Tohatsu 8 HP. It had its carburetor and propeller changed, so it's like a 9.8 HP.

Best regards, Jim.