Cord

iTrader: (2)

Well, I had a real enjoyable weekend on the Mississippi. Things got kinda rough there on the way back. A bunch of cruisers were throwing some really big wakes. Not exactly LOTO water, but there were some huge rollers. Well everytime the boat went airborn the engine would lay down. When the boat would land the engine would be sputtering and missing. Sometimes it wouldn't be too bad, once I almost fell off of plane before it came back. I'm thinking that the issue is fuel related and that I'm dumping excess fuel in when in the rough. Currently the floats are set level with the plugs and the fuel pressure is at 8psi. Other than this one complaint, the engine runs like a top. Does anybody have some suggestions? Anybody experience this problem before?

Oh, by the way, the carb is Holly 850.

formula31

Does that carb have the vent splash tubes installed in the metering plates? Mine used to act like that in rough water until I put those in.

Cord

iTrader: (2)

Are you talking about jet extensions? It's a little tube that pushes into the jet to extend it further into the bowl. I'm not familiar with vent extensions.

Waterfoul

Tim, take the breather off, do you have two J shaped tubes coming out of the vents? The J shape keeps fuel from splashing into the vents. Or try adjusting the floats a bit.

formula31

No, these are plastic rectangular tubes that attach to the top of the metering blocks (vent) and extend into the float chamber. Ill try and get a picture tonight when I get home.

mr_velocity

The J tubes keep all fuel spashing out of the vents directed into the carb. This is part of what makes a carb USCG approved. If you think you are getting fuel spashing up the vent, try putting a 2" piece of rubber hose on the tube and run it again. Make sure the hose fits tight so you don't "swallow" it.

Recheck the the float level, also check to see if you have plastic or brass floats. My Holley 830s came though with plastic floats, changing them to brass floats solved the problem. Haven't seen this problem on my 1050 dominators.

Cord

iTrader: (2)

If I remember correctly, the carb doesn't have the J tubes. It has the standard slash cut vents. I do recall a tip about putting a piece of hose over the vents thus tying them together. Well, hopfully that'll solve the problem. Thanks for the help guys!

formula31

The purpose of the J-tubes (external) is to direct any overflow from the float chambers down the throat of the carbs. I dont think this had anything to do with your problem Cord. The float chamber vent splash tubes are internal and altogether different.

Cord

iTrader: (2)

Oh, you're talking about those little rectangular plastic tubes. I thought the carb had them, but I'd have to check to make sure they still exist.

formula31

Yup, those are the critters. I though all Marine Holleys had them and I think they are really needed with big waves and such.