Tohatsu 9.8 2 Stroke Service Video

[Steve509926]

I've done the first part of the service on my 9.8 Tohatsu.

Its the first time I have serviced an outboard and I wanted to show others who have never serviced an OB before how easy it is.
No doubt I will have made some rookie errors and/or done things differently than some seasoned pro's, if I have, I'd be grateful for some feedback.
Also, has anyone any suggestions as to what the white deposits are as shown in the first part of the video.

https://www.youtube.com/watch?v=CHMxncWqDB0

[Fenlander]

That white corrosion fits in with a little used sail boat locker motor and is nothing to worry about.

I've noticed across all makes of portable outboard if crusty white corrosion is to appear anywhere it is usually at the head/block interface. I think it's where the face edges are unpainted but not 100% covered by the gasket.

If it is ever present on a used OB I buy then I gently remove with a small brass wire brush. If the paint is missing to any degree I replace that but usually just spray with corrosion protection or WD40 oil of some type.

The video is fine and I agree with not stripping that very clean carb as it's been running well too. Look forward to part 2.

[Steve509926]

Originally Posted by Fenlander

That white corrosion fits in with a little used sail boat locker motor and is nothing to worry about.

I've noticed across all makes of portable outboard if crusty white corrosion is to appear anywhere it is usually at the head/block interface. I think it's where the face edges are unpainted but not 100% covered by the gasket.

If it is ever present on a used OB I buy then I gently remove with a small brass wire brush. If the paint is missing to any degree I replace that but usually just spray with corrosion protection or WD40 oil of some type.

The video is fine and I agree with not stripping that very clean carb as it's been running well too. Look forward to part 2.

Thanks for the white corrosion/deposit explanation it makes complete sense.

I'll add that explanation & WD-40 protection into the part 2 video.

[Steve509926]

White crud removed, brushed off and OB painted. Thanks Fenlander.

I'm completing the service today, I've check the anode, it's fine, hardly worn so I won't be changing it. However I'm interested to see if it has lost any volume.
Has anyone got a new Tohatsu 9.8 anode which they could weigh for me so that I can compare it to the weight of the one fitted to my OB?

[Fenlander]

That looks loads better. I've probably said elsewhere after each use I very gently rinse under the hood (unless away for a few days then it gets done at the end), let it dry while I'm running in the flush bucket then spray with WD40 or better. That seems to keep them really nice year after year.

Re the anode I don't have a new one but volume loss is very noticeable as it becomes deep pitted.

[Steve509926]

Originally Posted by Fenlander

Re the anode I don't have a new one but volume loss is very noticeable as it becomes deep pitted.

That's good to know that they become deeply pitted, I thought they would have lost volume evenly.

[Fenlander]

About 50sec into this video gives a good comparison. In truth with leisure use daily launch outfits they stay good for ages.

https://www.youtube.com/watch?v=1mRfXLfTLZQ

[Steve509926]

Part 2 of the service includes the replacement of the impeller and refilling the gear oil. There is a "Part 3" which shall highlight the problems (stupid mistakes!) that I made.

https://www.youtube.com/watch?v=wkQa2tQGIJI

[Steve509926]

Hopefully highlighting my mistakes will help the first time servicer not to make them:-

https://www.youtube.com/watch?v=9SxWQ2bbVw8&t=4s

Go for it, it much easier than you think and you learn how your OB works.

[Fenlander]

>>>and you learn how your OB works

Indeed. My learning from teens onwards was from my late father who restored vintage motorcycles stripping them down to the last nut and bolt so they ran like new, similarly with antique clocks. It was a good grounding in all things mechanical that has stood me in good stead ever since.

There is a comment from someone on your YouTube video part 1 which could be very misleading and needs addressing. It says your non-start/running could have been from the carb bowl gasket seal being imperfect or screws not tight enough so pulling in air and causing the engine to stop.

This shows a complete lack of understanding to what makes a carburettor work. The whole principle of a carb is that the pressure in the air intake throat (Venturi) where fuel from the jets comes out is lower than the atmospheric pressure on the fuel in the float bowl. You could say the atmospheric pressure in the float chamber is all that pushes the fuel out allowing the engine to run. So a poor seal at the float bowl gasket causes annoying fuel leaks but as the float chamber is already vented to air then air ingress is not the issue.

In any case the jets pick up from close to the bottom of the float bowl so the only reason they would suck air is if the float is stuck closed or there is a fuel supply issue further towards the tank causing the fuel level in the float chamber to drop below the level of the jet lower orifices.

The tightness of the float chamber screws is a complete red herring with the non-running issue you suffered.

[Steve509926]

Thanks for the insight Fenlander much appreciated,

I will copy and post that on to the YouTube comments so that anyone reading it is not mislead, which I could have been if I hadn't already diagnosed the likely cause.

[Fenlander]

Yes because if you believed the carb float bowl gasket theory there is a danger of stripping threads on the screws by over-tightening or spending out on an unneeded gasket. It's an o-ring anyway not a compressible paper gasket and o-rings only need the screws nipping up to seal properly. That's one of their advantages.