Tohatsu 9.8 ,4 stroke

[Moorsman]

Hi all ,I have the above and sometimes just will not start ,if I over prime it can it flood and stop it starting,the bulb never gets hard ? Normally all my other oatboards the bulb gets hard

[Fenlander]

Are you talking about the primer bulb in the fuel line or a primer bulb on the front of the outboard near the choke knob?

What sort of age is the outboard? Has it always been hard to start? Does it run and idle well once warm?

[Moorsman]

Hi fenlander ,the primer bulb ,it is only three years old not done many hours ,if it does start runs well ,never really know if it will start ,trying now not priming it !

[Moorsman]

The bulb in the fuel line ,I have noticed petrol over flowing from the top of the carburettor when i press it but should it make the engine flood ?

[Fenlander]

You should be able to get the primer to go hard and normally if it doesn't then a new primer bulb is in order... I had the one on my new Suzuki 20 fail within its first few months.

But you may have a different problem... the float needle should just allow fuel to fill the float chamber and then shut off which is the point the primer normally goes hard. Fuel shouldn't overspill.

So looks like you need the carb off to see why the float needle isn't shutting off.

You will need the float height setting from a repair manual to check it out fully but you may find something obvious like a spec of dirt or split needle rubber tip.

[Moorsman]

Thanks very much good onfo ,the carb has been cleaned by two marine mackanics but I think you must be right about the float being wrong that’s why it over flows ,cheers

[Fenlander]

I'm assuming your motor is the same as in this video sold as Tohatsu/Nissan/Mercury/Mariner....

https://www.youtube.com/watch?v=0Gi8g50jC7A

I have the Mariner version here at the moment and I'm overhauling the carb. As a matter of interest it has a float problem where the top of the float is hitting the body of the carb inside the float chamber before it fully shuts off the fuel.

You can't adjust the float like you could in the 60s so a new float and needle is on order. It's not a fault I've seen before but can only think it has either been fitted with too short a float needle (unlikely?) or the plastic tab on the float has bent/distorted over time.

See in another video where the guy takes the carb apart, at 4min you can see the float hanging from the plastic tab....

https://www.youtube.com/watch?v=39kvIylvgbI

[Moorsman]

Thanks very much ,very interesting,I will check it .