Engine flooding episode

[Laker]

Yesterday , a beautiful Sunday , I boarded Sabina with my family for a combined test flight of a new North Sail A3 asymmetrical spinnaker / last sail of the season. After pre setting the asymm I hit the starter on the reliable Atomic 4 and it fired right up. I was bit hasty clearing the choke , and the engine died.That is common in cool weather ; I was impatient. So I pulled the choke again and hit the starter , got an instant restart. After 20 seconds or so the engine started faltering as it usually does with the choke pulled , so I pushed it in. Engine cleared , ran for 30 seconds or so , faltered and died. This was new. I cranked the starter , with and without choke ; it fired 2 cylinders with choke open but could not sustain itself. All indications were of a flooded engine. Water supply off , ignition off , swapped out the plugs. Rearmost 2 were soaked in gas , fwd 2 carbon coated. Water supply still off , I hit the starter with choke open & wot. I got the budda budda bubba bup bup bup bup buddabudda VROOM of a flooded engine clearing itself. Let it run for another 30 seconds , shut it down , opened water supply and restarted. Clean start , but after 45 seconds or so it gagged and died - FLOODED AGAIN !!! Now I was scratching my head. I was about to cancel the boat ride , but opted for one more try. Pulled and cleaned plugs , (same plug indications ) , water supply off - this time FUEL supply off , cranked with choke open & wot. Got the same sound effects as above , engine cleared , opened water supply , ran well for about 1 1/2 minutes until it faltered lean due to closed fuel valve. I decided to let the engine run while I opened the fuel valve , knowing that if it flooded again the carb was gagging the cylinders with gas. With supply opened the engine resumed normal running ; minutes passed ; shut down and restarted many times all normal. I tossed off the docklines and we had a beautiful sail.

Float stuck? By shutting fuel valve I emptied the carb bowl and whatever was wrong in the carb corrected itself? Anyone have a similar experience and/or explanation?

Thanks in advance , Laker

[ndutton]

I concur. Float stuck open. The question now is why?

[Marian Claire]

How is your throttle set when you start for the first time, cold? You mention WOT later. Your start up, 20 second falter as normal with choke pulled, just does not match what I have experienced. As usual more question than answer. Dan S/V Marian Claire

[Laker]

My normal throttle setting for cold start is intended to be high idle , but I usually get a good rev and have to pull back real quick. No sense spooling up a cold engine with no load. I went to wide open in an effort to clear the flooding. In my formative years with car engines the standard procedure was to remove the air filter , shove a pen into the carb to force the automatic choke to stay open , slowly press the pedal to floor- trying to avoid activating the acceleration pump - then crank w/ wot till she cleared. CK

[Marian Claire]

Thanks. That is the setting I shoot for also. The RPMs rise as I slowly disengage the choke so I counter by slowly throttling back to keep the RPMs around 1400.
As suggested could be a piece of crud intermittently keeping the needle valve from seating. Was there any fuel in the flame arrestor area? Have the plugs been fouled in the past? Any gas sheen on the water when you start up? Sounds like you have been running rich from the plug report. Would severely fouled plugs give you the same problem?
When you say "swapped out the plugs" did you install new? Cleaning or replacing with new plugs seems to have "solved " the problem but for how long?
Nag nag nag. Dan S/V Marian Claire

[Laker]

" Thanks. That is the setting I shoot for also. The RPMs rise as I slowly disengage the choke so I counter by slowly throttling back to keep the RPMs around 1400.
As suggested could be a piece of crud intermittently keeping the needle valve from seating. Was there any fuel in the flame arrestor area? Have the plugs been fouled in the past? Any gas sheen on the water when you start up? Sounds like you have been running rich from the plug report. Would severely fouled plugs give you the same problem?
When you say "swapped out the plugs" did you install new? Cleaning or replacing with new plugs seems to have "solved " the problem but for how long?
Nag nag nag. Dan S/V Marian Claire "

Fuel at spark arrestor : None slopping out , definitely smelled flooded.

Gas sheen on water : Sabina has all of 8 ft of overhang at the stern ; no sheen observed , but probably , when it was flooded. Not normally.

Running rich / plugs - yeah , when it was flooded the two which managed to fire were carbonned up , otherwise plugs look normal.

Swapped plugs : I had a set onboard which had been treated in a plug cleaner. They were in like new condition ; that was the "buddabudda gag-gag VROOM start-up , followed by flooding again after about 45 seconds of clear running.

The key bit of evidence here seems to be that , after getting a restart and clearing the cylinders with fuel valve CLOSED , and running for about 1 1/2 - 2 minutes until the engine began to falter for lack of fuel , the re-opening the valve , the malfunction did not reoccur. Some sort of correction took place when the carb bowl was empty (engine running , fuel line valve closed) , or as the bowl refilled , engine still running with valve re-opened.....

[Dave Neptune]

Question

Laker, do you have a polishing filter in front of the carb? If there is something in the lines that can hold the needle open it should get filtered out and never make it to the carb.

If you do have the filter in place did you remove the fuel line between them recently? Old hoses often loose chunks inside when being pulled off & on. Those type of chunks are often the needle culprits.

Dave Neptune

[Marian Claire]

Laker: Thanks for putting up with all my questions. I still can not grasp the two fouled plugs after a single event of flooding the carb. I just think you may have had a short term needle valve issue and a preexisting running rich condition.
Dan S/V Marian Claire

[Laker]

The two fouled plugs were soaked in fuel. Back cylinders - low end. As to pre-existing running rich , I ran the same set of plugs for 3 years without fouling. I believe it all happened in the isolated incident. Apparently raw fuel was being fed into the manifold. The only remaining question , I think , is what to do next. There is the old axiom : If it ain't broke, don't fix it. Me being me , since the little mill is now running so well , I'll probably hose the intake with carb cleaner , run it a bunch , and leave it be.

CK

[JOHN COOKSON]

Have a look inside the distributor cap for tracking and shorting between terminals.
Also have a look at the engine while it is running in the dark at night. Maybe just maybe there is shorting of the spark wires which you temporally "fixed" when you moved them around.

Nag,nag,nag. John D\B TRUE GRIT

Edit: Also spark plug wires not connecting properly to the distributor cap and or spark plugs.