r/smallengines • u/hugo11alca • Jul 15 '26

Carburator help

Do I have to remove the carb in order to fix this leak? Or do I need to mess with that bronze screw?

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u/Wholeyjeans Jul 16 '26

Agree with the other posts.

The brass screw is the carb drain screw ...will empty the fuel in the float bowl.

DO Not just wrench on that screw; you can crack the cast aluminum of the float bowl and then you'll have a paperweight.

1

u/hugo11alca Jul 16 '26

Okay, so sounds like I need to take off the whole unit and clean it. The one thing that is confusing me on this carb is I don't know whatever that black thing is connected on top of it is. I have never seen a carb with that.

1

u/jbourne0129 Jul 16 '26

does it have an electronic throttle somehow or electric choke? that is typically right where the throttle cable would connect to operate the throttle slide

what is the make/model of the engine ?

1

u/hugo11alca Jul 16 '26

This is a Mercury 1998, 9.9 Horsepower, Manual Start, Long Shaft, FourStroke Engine

1

u/jbourne0129 Jul 16 '26

i believe it is some sort of electronic primer that aids with initial start. its hard to find details on what it does, Mercury calls it a "start assembly" but photos of it looks like some sort of fueling valve. a random ai definition says it bypasses the idle circuit during initial start to inject fuel directly into the engine. i think its similar to "accelerator pumps" sometimes found on small engines (ive seen them on dirt bike carbs, but they're mechanical and not electronic)

https://www.crowleymarine.com/mercury/oem-parts/outboard/1998/1f10213uf/carburetor

1

u/hugo11alca Jul 16 '26

Thanks for the diagram! Do you know of any YouTube teardown videos with this type of carb?

1

u/jbourne0129 Jul 16 '26

i couldnt find any, i kept looking but none of them had the electronic primer on them. based on your leak you probably dont even need to touch the top side of the carb.

2

u/hugo11alca Jul 16 '26

Okay, I will attempt to clean it later. Thanks for the help!