carburetor problem Honda BF 90

T

thataway

Active member
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:

Carb1.sized.jpg

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!
 
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
 
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.
 
starcrafttom":3q0midkd said:
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.
Click to expand...
Not me Tom. Our engine is a Suzy DF90, fuel injected. :thup
 
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.
 
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
 
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.
 
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
 
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 :teeth

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…
 
Bob,

If I store my old Honda 45s they way you are supposed to they get a stuck float or two every spring. Unfortanately I have a lot of experience with you have going on. I know this is crazy, but I put Stabil in the tanks, don't drain anything, and squeeze the primer bulb every 2-3 weeks until they are firm again. I have never had a stuck float since adjusting my storage procedure.

My advise if soaking, tapping, and time hasn't worked, is to open the carb drain and give it a few blasts of compressed air. It has worked on mine before as a last ditch effort to avoid pulling the manifold. Sometimes running the trim up and down helps too......I feel your frustration here!

BTW, if I remember right, the 90 is very close to the 45s on the carb setup. It only takes a few minutes to get the entire manifold off with all the carbs. It really isn't to hard. Getting gaskets on the parts store shelf might be harder - at least it is for me......Good luck and I hope you fix it soon!
 
Yes, from reading and looking at the diagrams/photos, the same basic carb is used from the 25 on up thru the 150. The linkages are a bit different. Re-sync and getting the linkages correctly aligned are probably the most difficult part of removing the manifold, air filter. Just time in a busy schedule, and the boss wants to do the final clean and pack the boat, so we can go break some ice in Lake Superior…..

Alaska and Florida do both have their challenges with fuel. Unfortunately part of the year the C Dory is left for 3 months where I could not squeeze the primer bulb--but that is a technique well worth remembering. I had also considered the compressed air--The carburetor cleaner I am using has a pretty good pressure in it, and I seal the drain tube around the output, so the float gets a good blast. I probably would have fired up the compressor, and tried that, but…..

This morning, I gave one last good blow--plastic hammer to a piece of plastic held against the carb. Drained the solution which soaked the bowl thru the night, and squeezed the bulb--it came tight, with a couple of squeezes-- no more leak!

The engine fired up after a few cranks, and low speed idle is a little rough. I have filled the other carbs with cleaner, and have carb cleaner in the fuel, so I 'll see if that takes care of the rough idle. It does not stall on shifting, so I suspect with some fuel, it will smooth out.

Thank all of you for the comments and suggestion, and hopefully this discussion will help someone else.
 
I am so glad to hear that. When mine used to do that, an overnight soak would often free them up. It's good you didn't have to tear it apart. After all that carb cleaner runs through the carb, and you actually have pure gas in the float bowls, you can turn the idle mixture adjustments to smooth out the idle. Sometimes a little piece of crud gets stuck on the needle part of the screw and just a little turn lets it pass on by. If they are anything like mine, just a quarter to half turn or so does the trick. Then, put it right back where it was when the idle smooths out. If this doesn't work you might have some deposits in/on the stupid emulsion tube, or even a crack - which is very common. However, the idle mixture adjustment screw just might do the trick and I'd screw (pun intended) with those first. This will not mess up you carb synchronization.
 
Thanks---great idea, and I'll get to that! It was interesting to see when I first ran new gas thru the carb that was sticking--I had a little crud in it. After soaking all of the bowls in carb cleaner, and then draining, flushing with pure gas, again, each carb had a little curb. Darn Calif. for lack of sanity and not allowing pure gas for outboards…. (I love to blame California for all sorts of woes--I was 5th generation--but not the first in my line to leave. My kids love to defend California, and tell me why I should have stayed and paid their taxes! )
 
I just pulled the manifold, and opened the carbs to replace the idle tubes, on one of my motors. It really wasn't a bad job. It looks far worse then it is. The choke and throttle linkage just pops off of the carbs(mine were ball socket affairs). You don't have to mess with anything that needs adjusting.

Pop the two linkage bars offThrottle and choke)
Disconnect the fuel lines at the opposite ends from the carbs.
Loosen the nuts on the bracket that holds the linkage in the bracket, and slip them out, and then ease the barrels out of the throttle wheel(I'm assuming this is similar to my 90's).
I had two bolts that held the throttle linkage bracket on the motor. I had to remove the bracket to get the manifold off.
With everything out of the way, remove the bolts(I had two nuts on studs as well).
Remove the manifold/carbs/air box as a unit.
Remove the airbox from the carbs.
Repair carb(s).
Clean gasket surfaces, and reinstall new gaskets.
Replace the intake assembly.
Reconnect throttle linkage, bracket, choike etc., in reverse order.
Reconnect fuel lines.

It's not that bad of a job. Don't tinker with any adjustment, and you can put it right back together again. If it was running good before, then you shouldn't have to do anything but RandR the manifold and carbs.
The whole thing took me about 3 or 4 hours from start to finish.
I had to replace the intake to head manifold gasket, and the gasket between the carbs and the air intake box.
 
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