blue thunder

Was catching a little air the other day on my way to Jelly Fish Joels off a 50 footers wake. Entered at WOT then did the standard pull back of throttles after liftoff. Did the standard reentry WOT blast for a smooth landing. This time though it seems the port engine stalled in mid flight (holy friggn right turn batman!!).
After getting things under control again and stopped (middle of the shipping channel btw) changing my drawers, and raising hatch, I note pools of fuel on intake of stalled engine. I quickly break out he quicker picker upper (bounty) as I don't like fire much anymore. Get that cleaned up, remove flame arrestor and, figuring my float needle dislodge thought I'd give a little crank to see where it was coming from. Bad idea... flame god errupted from Qjet and when engine didn't start, kept burning. Oh ****... flame arrestor on quick to douse flames, fuel valve turned off and head for home on other engine. Cruised for 2 plus hours in the beautiful 100* sunshine heading towards home, and finally decided to take another peak. This time I removed the kill switch for that motor. Remove flame arrestor and almost immediately this time saw the problem. The secondary air valve was open, and upon further investigation saw the metering rods had jumped out of their seats.. WTF!!! Broke out the needle nose and within seconds had them working fine again. Tried to start engine with throttle wide open... nothing. Oh **** forgot kill switch. Tried again and bang, roared to life. Let run a minute while buttoning things up then oh ****... stalls again. Oh yeah, fuel valve off. Starts right up again and I fly home like nothing happened.

My question is.... how the hell does this happen? I never heard of metering rods jamming. I rebuilt these carbs over winter and they work great. Any suggestions what to look for? I'm glad I was alone... my wife would have had a freaking cow!!!

BT

Vinny P

I have never heard of that one!! How the hell can the rods pop out??? The taper at the bottom of the rods should be long enough to still be in the jet while at W.O.T. Between that and the actuator arm they pin to should be enough to hold them in place. Maybe with a real good jolt, it is possible that they dropped out of the actuator arm and fell into the bowl. I guess you were lucky, it could have been far worse...

blue thunder

Yeah Checkmate, going in I took a pretty good jolt. The rods were still in place but one of them was clearly bound and holding open the secondary air valve. I couldn't free it up by hand and needed to use a needle nose to pull them up... then they dropped back in. I'm going to check out the whole carb this weekend and make sure it hasn't had some other failure I didn't notice. Any other thoughts?

One strange thing is the fuel outside the carb. When I got back on the throttles, the only thing other than the hard right turn I was noticing was the rpm on the stalled motor (didn't know it was stalled) at 2500rpm. The other tach was at 3500. Is it possible the stalled engine was being driven by the prop (still in drive) and the fuel pump kept pumping. I noticed this same thing on a tach of when I blew an engine at WOT last year. The engine seemed to be turning (driven) through the prop when it wasn't running. Does this happen?

BT

Vinny P

BT;

Maybe I am reaching here but the only thing that comes to my mind here ( at least about the fuel on the intake ) is that maybe it is possible that the engine stalled when the secondary needle came out of the jet due to flooding with fuel. Is it possible that the engine then ran in reverse for a short while ( being driven by the prop ) and pucked up all the fuel in the intake????? I don't have any experience on a twin engine boat, would the other running engine have enough power to move the boat for a while and also drive the stalled engine from the prop in reverse causing this condition???

blue thunder

Checkmate... that is what I was wondering about the engine being turned by the prop. The pukng of fuel probably occured because the secondary throttle plate was closed at mid flight, and the metering rods were effectively wide open with the air valve open. For a short time the engine would have continued to turn over from inertia. That is probably when the fuel dump happen. Quite unpleasant all in all.

If the engine did turn backwards momentarily, then I really dodged a bullet because I think the exhaust valves would have breifly turned to intake valves and intake valves to exhaust. That would explain the puking out the carb??? No hydrolok though....

BT

Cord

Can't really help you with the carb problem, but the next time that you have a carb fire, try cranking the engine with the throttle open. They will usually go out.

blue thunder

In my case Cord that would have just puked more fuel onto the fire. I should have removed the kill switch before cranking.
Thanks for the thought....

BT

mopower

Prop can't drive the engine on a Bravo. With the drive in forward , turning the prop forward , it will just slip

blue thunder

Dad gum... I believe mopower is right on that. Thanks for the wake up call mo.

BT

Ted G

I would bet that the metering rod holder holes are slightly worn and allowed the rods to cock slightly. I would order 2 new ones and put them on just in case. You may also have bent the end of the rod slightly which allowed it to move. Another possibility is that the pointy headed engineer that designed the carb never thought we would do the things we do with them in boats and never took those kind of forces into account But I have never heard of that happening before.