carburetor problem Honda BF 90

[thataway]

I have removed all of the old fuel from the tanks, and put in new fuel. When the engine was shut down, the oils were changed, and carburetors drained. The tanks had 2 gallons on the port and 6 gallons on the starboard tanks. This was treated with Stabil and Startron--but it smelled stale, so discarded. As I was priming the carburetors, I noted fuel leaking from under the cowling. On examination, the fuel was coming from around the dime sized disc on the upper part of the carb:



The silver disc in the upper left corner. First any idea what this is, and why it is leaking? (Pressure relief?)

The engine was put up a little over a year ago, and running well then. I did kick it over, for a couple of turns (less than a second) and it appears that fuel is coming from under or around this disc.

I didn't find the exact part on the internet, but may have missed it somewhere.

Thanks!

[BrentB]

ok to guess?

fuel vent

[BrentB]

maybe float is stuck and causing the leak
m2cw

[BrentB]

I think the float is on the over side on the disk which I call a vent

[thataway]

Brent you are correct. My first thought was a stuck float--but this cover was so far from the bowl, it seemed to be too far away. I stopped by my Honda Dealer--yep--that cover is over the bowl vent--which runs thru the body of the carb past the air intake...

To un stick this (an easy job), you have to pull the entire manifold! (not an easy job) Hopefully a few taps with a bar, and putting some carb clearer directly into that bowl (which may be a trick) will take care of it….

So when the rain stops--it will be squeeze and tap--plus carb cleaner….

Thanks,

Bob

[BrentB]

good luck...... atleast it is not held together with Bostic

[starcrafttom]

Yes stuck float. someone at Friday harbor last year had the same problem and I fixed if for them. Terry I think or maybe it was peter. Any way give it a tap and clean it with some carb cleaner.

[Jazzmanic]

[starcrafttom]

must have been terry

[thataway]

Lots of taps, filled the bowl twice with carb cleaner (thru the drain tube)--still stuck.

I am thinking of leaving carb cleaner in the bowl overnight.

Any other ideas? Usually they break loose fairly easily… Interesting that there was a little particulate matter when I drained the bowl the first time, getting out new gas. When I drained the bowls before storing the boat, the material was clean coming out of the bowl. There should have not be any gas in the bowl afar draining it.

[UncleRichie]

Some times you can open the drain on that carb and pump the primer bulb and run some gas through it this lets the carb float drop and hopefully washes the junk out of the needle valve . before you hook up the gas line in the spring pump some clean gas through it , not much fuel left in the bulb but what is there can get perty bad over winter.
Richard

[thataway]

Rich, I suspect that the float is stuck in the down position and float not rising. I ran all of the fuel out of the lines, and filter when I put the boat up. When I pulled the old gas out--I pumped until I only got air. Then I put clean fuel in the tanks--and pulled the new fuel into the empty Racor, as well as the lines--plus I replaced the bulb, and the exposed fuel lines--the last 6 feet.

Another friend suggested that we try and "tickle" the float with a piece of wire--but I was not able to get a wire into the bowl, since there is a right angle where the bowl drain valve is located. (Even tried with the valve screw out, so I could directly see the wire. )

Of course there is always the possibility that the float is damaged…seems unlikely on a 6 year old engine--but It could happen. Most of the floats are plastic these days…

Thanks.

[BrentB]

someone said use WD40 to lube parts

[Moxieabs]

Dr Bob,

Every time I've been confronted with a pressed-in cover plate on a carb there has been a spring controlled enrichment needle valve behind it. In your photo there appears to be a "notch" in the aluminum carb casting. Does this notch exist in the other 3 carbs? (it's dark and raining here in ME or I would pull the cowling and look for myself) If the notch is normal, perhaps the disc is loose/distorted? There should be an overflow vent tube from the float bowl to drain fuel if it is a stuck float. If the "notch" or warped disc is the problem, perhaps some fuel safe epoxy judiciously applied could solve the problem.

Dave

[thataway]

Dave,
The other carbs all have exactly the same plates. There is even a U Tube video showing the fuel pouring out from these vents in case of a stuck float valve. So I fear we are on the right track--just why did it happen--is the mystery. It must have been that E 50 I was forced to use in California two years ago

My best guess is that somehow there was enough "gunk" already in the bowl from some use of the ethanol. We had stored the boat for about a month at Lake Powell, and had not drained the Carbs then. I had actually used ethanol fuel in Calif--since pure gas is almost impossible to find in S. Calif shortly before we stored the boat at Powell. The boat ran well, but I suspect that some gum or varnish had already formed and during the time the float was at the bottom of the bowl, it became adherent. Now that I have seen the carbs torn down, I realize that the wire will not work, even if I were to get it into the bowl--which will not happen….

I am also concerned about the effect of Carb cleaner on the rubber and other parts of the carburetor. For example the valve tips are rubber on these carbs.

It may come to tearing off the manifold and taking the carb (maybe all of them) apart--then having to re-sync them…