De-winterized! Carb Issue

[JOHN COOKSON]

Been There Done This - It Wasn't Fun

After 3 or four tries without so much as a "pop", I knew something was wrong. Ran back down below to the engine compartment and was immediately greeted by the odor of raw gas! Fuel was dripping out of the carb throat, leaking through the joint where the flame arrestor attaches!
It seems the float valve was stuck open, and the pump was just flooding the carb with gas!
After a frantic cleanup and ventilation, I had to pull it all apart again to open the carb and see what was going on. All the while I'm thinking "Did I forget to put the needle valve in? Or did it fall out unnoticed while I reassembled the float hinge?"

I (make that we) could have had a fuel explosion in the engine room.
Now my SOP after any carb work is to crank 7-10 seconds then check the carb. Then do another cycle.
Also this gives the starter motor a chance to cool off and the battery a chance to snap back.
Once the engine starts I immediately shut it down and check the carb again.

TRUE GRIT

[Dave Neptune]

Pops

I was aboard a boat many years ago with a similar issue although it was a 4 cyl Chevy in a ski boat. When it went pop it blew the cover open, but no fire insued.
The only way I start my beastie after it has sat is at the engine!!! I have to open the cover to turn on the fuel valve anyway! I have a remote start switch wired into the box so I give her a few cranks to get the oil moving and then turn on the key and fire her up. If there are any leaks or issues I will see them. After we've been sailing or sitting at the island for a few days I just start the blower and fire her up. I do shut off the gas when ever I get back into the slip and let the fuel run out. I have always felt this to be a good practice as initial start ups after sitting are usually when this kind of stuff happens.
Edward nice catch on the PCV valve, a high idle is one of the first signs of eminent failure. Fortunately they don't fail often. Perhaps tracking the various brands may yield a "better one".
Also Ed you are very lucky you went to look rather than cranking til the batteries are dead, seen far that too many times.

Dave Neptune

[edwardc]

I (make that we) could have had a fuel explosion in the engine room.
Now my SOP after any carb work is to crank 7-10 seconds then check the carb. Then do another cycle.
Also this gives the starter motor a chance to cool off and the battery a chance to snap back.

I typically crank no more than 5 seconds, and then give the battery a moment to snap back too. And any time I'm messing with the carb or fuel system, I'm down there with my nose repeatedly checking for fumes.

I have a remote start switch wired into the box so I give her a few cranks to get the oil moving and then turn on the key and fire her up.

I have one too, but it is a portable unit with "clamp-on" contacts. I don't like to use it in these cases, when there's a potential for fuel leaks, because one of the clamps could pop off durring starting and draw a spark.

...you are very lucky you went to look rather than cranking til the batteries are dead, seen far that too many times.

"Chance favors the prepared mind"! Thanks in no small part to the collected wisdom here!

[Dave Neptune]

Pops II

I have one too, but it is a portable unit with "clamp-on" contacts. I don't like to use it in these cases, when there's a potential for fuel leaks, because one of the clamps could pop off durring starting and draw a spark.



That is why I wired one in permanently. It is also quite hany when working on the engine.

Dave Neptune

[edwardc]

Update on carb flooding

Well, it took two weekends before I could get back to the boat to install & test the carb again. This time, I hooked up only the fuel line and tested with pressure before going further.

Frustratingly, the gas started flowing out of the throat again! So once again, I unmounted the carb, drained it, and tore it apart. Everything still looked perfect inside.

As I sat there staring at the carb parts spread out in the cockpit, it hit me. I picked up the float, and shook it close to my ear.

Slosh, slosh slosh.

Although the outside appeared intact (even under a microscope!), and the surface was dry with no sign of a weep hole, one of the float bodies was definitely about half-full. This explained why the float valve sealed properly when I tested the empty carb by holding it upside-down, but it would not hold against the fuel pump pressure in a live test. It just didn't have enough flotation. This must have happened over the winter layup, as there was no problem like this when I winterized last November.

In the attached photo, I balanced the float on the edge of a screwdriver blade. You can clearly see that the float on the right is much heavier than the one on the left.

I thought i was out of business until I could order a replacement float. But while looking at the website, I noticed that the same float fits both the old and the new style Zenith carbs. And I just happened to have a beat up old-style Zenith in the bottom of one of the lockers! I pulled the float out of it, installed it in the good carb, and tested again. Success! No more gas leaking out of the carb!

Put on the new PCV valve, connected the choke & throttle , and fired her up. Once things warmed up, I fiddled with the idle & main jet adjustments and got her running great.

Next step was to hook up the Oxygen sensor and the Cyberdyne mixture gauge (identical to Hanley's) and see what it could tell me.

But that's a story for another thread.

[Dave Neptune]

Slosh

Ed, nice find! It is ususally something simple with such a simple engine.

Dave Neptune

[Administrator]

Great catch, Ed! I just sent Don a note, reminding him to mention this in the forthcoming carb mini-video.

Bill

[marthur]

I will echo the others: Good eye!

I have had the same thing happen to one of my outboards when the finish on the cork float failed and the float became "gas logged." However, I didn't think of it until you came up with the solution.

Here is a question for the crew: Imagine being on the hook in the middle of nowhere (where I like to sail, actually). If you discovered this is there a quick fix you can think of? Specifically, what Macgyver style methods can you suggest to drain and seal the float with the ordinary materials found in your tool box?

Alternatively, could you cut off the bad float and have the carb function with just one?

Mike

[Bold Rascal]

Good for you Ed

Hope all continues to go well for you and hope to see you on the bay someday.

[edwardc]

...Here is a question for the crew: Imagine being on the hook in the middle of nowhere (where I like to sail, actually). If you discovered this is there a quick fix you can think of? Specifically, what Macgyver style methods can you suggest to drain and seal the float with the ordinary materials found in your tool box?

Smart-Ass answer: Install your spare float!

More Serious answer: The floats appear to have a vent hole on the top, probably to allow the air pressure to equalize when the halves are soldered together. It seems to have been soldered shut afterwards. You should be able to open it with an icepick or something sharp, as solder is relatively soft, drain it, and reseal with JB Weld or Marine Tex. Or, if you're really gutsy, and are sure the float is empty & dry, you could try to remelt the solder with a lighter.

Alternatively, could you cut off the bad float and have the carb function with just one?

No, it needs the flotation of both halves to put enough pressure on the needle valve to hold it shut against the fuel pump pressure.

[marthur]

Nice answers, I did not know about the vent hole on the top.

Here is a hint: If you use JB weld, cover it with a thin layer of super-glue. The JB I have in the garage is not resistant to alcohol (but it is gas proof). Super glue is resistant to both.

I once repaired a crack in the carb bowl of my dinghy outboard with JB sealed in superglue. Six months later it was still going strong, but I swapped it out for one from a parts motor.

[Dave Neptune]

Thanx

Mike, thanx I knew of the issues with JB and alchohol and keep JB & JB kwik in my ditty box at all times and now I'll add super glue. Learn somthin' new here on the forum quite often.

Do you know if the super glue will stand up to kerosene or diesel?

Dave Neptune

[marthur]

Cyanoacrylate (the chemical name for most brands of super glue) is resistant to kerosene and most oils.