What is cause of bowl vent leaking on Mercury outboard carburator?

Question

I have a 90 HP Mercury outboard motor. It has developed a leak on the side if the carburator thur the bowl vent the other two carburators are fine. Motor idles then stalls. Will a kit take care of this problem.

Answer 1

Hi i would check out your needle valve and float adjustment, they do have  a carb kit that will help , just take your make and model number off the side of the side  or in the front there is a metal tag that's ribbed on  and those number to a deal of out board's will get you the kit to fix it.  a few tool's and you could do it for less than 200 bucks

Answer 2

Good answers so far, but I would add; In most "kits" new floats are not supplied.

I would definitely build the carbs, AND put new floats in all of them. Composite floats can get saturated and not shut off the needle and seat.

Answer 3

I would clean and put kits in all 3 carbs. It probably is the needle valve sticking, but you might as well do them all while you're in there.

Answer 4

The kit should solve the problem.  However, you may want to remove the bowl and check out the float and needle valve.  It sounds like it is stuck open and not shutting off the fuel when the  bowl fills up.  It works very similar to the float valve in a toilet tank.

Answer 5

Yes I think a carburetor kit my rectify your fuel leak problem, there are four possible reasons why the carb is leaking.

1. needle and seat are worn out 2. needle and seat are obstructed with foreign material 3. carb float becomes saturated with fuel or is cracked and fills up with fuel 4. incorrect float setting. Any of these conditions will make the fuel mixture to the engine too rich and load up the engine causing it to stall out. After installing the new kit make sure the carb float is set correctly. Good luck.

P.S. Bill you be very careful any fuel vapours under the cowl and a stray spark could give you a unwanted condition called FIRE. Remove the cowling and make sure the engine is well ventilated God forbid if there is a fire it's easier to put out.