Fuel Sucker

"I have a 1990 Silverton 34C w

"I have a 1990 Silverton 34C with two 454/350hp Crusaders. The week-end prior to Mother's Day week end I ran the boat everything fine fuel consumption per floscan was normal. The Monday after Mother's Day, my wife and I left for a nine day cruise out of lake ponchatrain into th e Gulf of Mexico along the Mississippi Gulf Coast. As so as I fired up I noticed excessive fuel being used by my port engine.Bottom line I shut down that engine and continued on with one engine. I was traveling with a Trawler so no problem keeping up. I only used the engine when docking. When I got back I pulled both Quadrajets and had them rebuilt. Both were dirty and very cruddy. Put back on same problem. Changed plugs in both engines prior to trip, then changed plugs in port engine before restart with rebuilt carb. Swapped carbs on engines same results. Floscan shows 4-5gph at 650rpm on port engine 1/2 gph on starboard engine at same speed. I am a maintenance troubleshooter and have bee since 1968 and can usually find the cause of a problem, but guys this has me stumped. I found this forum by accident, did some reading and there is a great wealth of knowlege here. I hope some one can help solve my problem. THANKS"

Are you sure your floscan is w

Are you sure your floscan is working correctly? 4 to 5 gph is not unreasonable where as 1/2 gph can't be right or if it is and the carb is the reason you should find a way to clone it and your fortune will be made.

"Bill,

You didn't menti

"Bill,

You didn't mention why you changed the plugs a sceond time (first before start of trip and then again after installing rebuilt carb) on port engine. How did the plugs look? It sounds like you didn't run the port engine much anyway.

As Paul suggests, you just have a problem with the floscan sensor on the port engine. You swapped carbs and problem (whether 4-5 gph or .5 gph is correct, they are drastically different), so why not try swapping the floscan sensors?

Erich"

"Bill,

I tend to agree with

"Bill,

I tend to agree with the sensor swap. Do you use any filters prior to the fuel entering the sensors?"

"I'm still trying to under

"I'm still trying to understand the message here:
"Swapped carbs on engines same results."

Does this mean the port was still running rich or did it go with the carb swap, to the starboard?

If the problem is with the engine and not the carb, its mostlikely electrical or mechanical. You didn't indicate any abnormal noises so I'd lean towards electrical. Point gap on an older style distributor, Cap or Rotor corroded and won't fire or misfires, advance mechanism broke, etc.

you mentioned multiple plug changes but never any indication of their condition...??"

"OK, I changed plugs on both e

"OK, I changed plugs on both engines before my trip, this was just a routine maint. item along with an oil and filter change. Plugs in both engines looked ok. Changed plugs in port(trouble)engine due to excessive fuel problem. Plugs were carboned real bad.Also changed oil in port engine due to gas saturation in oil. As far as the floscan goes my engines both starboard and port at 650 RPM IDLE have never consumed over 1/2 GPH. Now PORT engine consumes 4-5 GPH at IDLE. I also can smell raw gas in port exhaust and also see the gas sheen on the water. Yes there are filters before and after the floscan. 2 Prior and 1 AT the carb. I am running DELCO-ELECTRONIC ignition 35000 volts. Starting to susoect problem could be manuel fuel pump dumping into crank case. Any thoughts or remedies welcome."

"The pump diaphragm being rupt

"The pump diaphragm being ruptured could do just what you are describing. There should be a plastic line (mine were yellow but they will darken with age) connecting the fuel pump to the carb, usually at the front over the fuel inlet line. If you can see any liquid in it, the pump is leaking. when the engine is running, if the pump is bad and leaking, the excess fuel gets dumped right into the primary."

"Well, that's interesting.

"Well, that's interesting. Engine flooding with gas and the carb is known good....

That much fuel getting into the engine, if thru the carb is easy to witness. Remove the flame arrestor and site down the carb bore with the engine running. Wear safty glasses and have an assistant with a fire extinguisher in hand. I don't think a fuel pump dump into the crankcase will get to the combustion chambers.
Are you sure you swapped carbs? They were both off at the same time..

edit; YES, mark has a great idea there."

Carbs were marked port & s

Carbs were marked port & starb.I always mark wires or components to double check myself. And yes I do have the tygon tube going from pump to carb.

did you get an odor ofo raw ga

did you get an odor ofo raw gas when you pulled the tygon tube when swapping carbs?

"I have decided,after consider

"I have decided,after considerable thought,to place a low pressure(4-7psi)electic fuel pump on the port engine. If it is a fuel pump problem that should solve it. If not I will really be at a dead end. I think we all agree that the only things that control fuel flow and the amount of fuel flowing, is the fuel pump for pressure and volume and the carb for amount of fuel metered into the engine through the primaries and secondaries. Engine load and RPM set the demand and frequency of delivery. If I have missed anything let me know.I won't be able to try the fuel pump idea for about another 10 days. You know work sure can interfere with really important stuff. Thanks for allthe response. Any other ideas or suggestions are always appreciated."

Be sure you wire the fuel pump

Be sure you wire the fuel pump through an oil pressure switch that shuts them off when the engine stalls. It's both USCG required and an important safety item.

Jeff

"Update: Found my fuel problem

"Update: Found my fuel problem. Took pump off this past weekend took to work Monday and being the inquisitive type, tore the pump down and found the diaphram to be in terrible shape. rubber missing around the part of the bellows that flexes the hardest and had a great deal of fuel seepage which caused fuel to be pumped into the crank case and caused fuel starvation for the carb. new pump will be installed Friday for week-end festivities. Thanks for all your input."

Guess what caused that? Ethan

Guess what caused that? Ethanol gas! Another near disaster caused by those bureaucrats that stuck us all with this crap without a public hearing--and they want to go to 15 % next!

Time to let our voices be heard.

Jeff

"Bill,

When you say it caus

"Bill,

When you say it caused fuel to be pumped into the crank case, I assume that it got there by being pushed up the Tygon site tube and into the carb. I don't think that this would starve the carb but cause an excessively rich mixture. Don't forget to change that oil which has been diluted by the gas.

Erich"