Carburettor draining Yamaha 3cylinder outboard

Pramsd · 10 November 2018, 12:27

Hi guys ,

Bit of a niche question - but does anyone have a clever trick, or know where I can buy a suitable tool for removing the bottom carb drain screw on my 30hp Yamaha 3 cylinder.

I manage with a lot of swearing and fiddling with a kitchen knife but it’s not pretty or quick! It’s in such a fiddly location I can’t get a spanner or a socket set to get it.

Anyone got any clever tricks?

Phil

beamishken · 10 November 2018, 12:43

If its just for storage run the engine with no fuel line untill it stops

matt h · 10 November 2018, 13:14

There isnt. Its only a standard deep neck ring spanner. They can snap easily tho

Tim M · 10 November 2018, 15:03

I've had this issue! In the end I decided the safest bet was to take all three carbs off. Bit of a pain but at least you know it's been done properly without risking breaking anything. The RNLI fit nice big thumb screws on these drain screws so you don't need a tool. Would quite like something similar.

Pramsd · 10 November 2018, 17:33

Thanks guys - deffo like the sound of those thumb screws , would be much easier.

I don’t really like the running the engine dry trick. I do that to a point every time I come in with the boat, but for winterising I like to drain the carb properly, blow it through with an air line etc.

Also always reluctant to run a 2 stroke dry.. I know its pedantic but they rely on lubrication in the fuel so it can’t be great for the cylinders to run it dry (appreciate that’s a properly cautious view)

Tim M · 10 November 2018, 17:42

Is it an auto mixing or pre mix model?

jeffstevens763@g · 10 November 2018, 20:16

So when you've run it dry how much fuel comes out of the float bowls.

I thought all cylinders were milled with tiny x's to hold oil for lubrication so the engine never starts dry.

Pramsd · 10 November 2018, 21:06

It’s the autolube version .. and a fair amount still comes out of the carb when I drain it..

I just wish the screws were easier to get to, if they were accessible i’d be tempted to drain them after every outing.

I’m paranoid because when I first got the engine it was a bit of a nightmare to sort, the carbs had been left full and the jets were so badly seized and clogged it took a blow torch and a lot of fiddling to clean them up.

Didn’t know that about the cylinders - would make sense for sure!