Engine not retaining fuel in carb.

Hi I have a problem with the gas on my inboards not staying in carb. You have to prime the carb in order to start. I have twin inboards 305 chevy mercruisers with quadrajet carbs. 1982. The carbs were rebuilt in 2004 when I repowered the engines. The boat has sat for 10 years and runs good when primed and started up.
I also have another thread on overheating and am still working on that.

if this is after a week or so, its not unusual....byproduct of the modern formula used for 'gasoline' nowadays....

Some of the ingredients in gasoline have a boiling point around 104 F, so, when you stop your engine, the residual heat of the engine ( 140 to 160 degrees) will immediately start the "evaporation" of the gas in the carb. At "room" temp, gas will totally evaporate in fairly short order.

I Don't know why my post didn't make it to thread. I will repeat what I said. The engine looses gas after shutdown of 5 minutes . What could be a possible fix to this ? Will I have to keep putting gas into carb every time I want to start. This didn't use to happen. BTW I have high octane fuel in tank .

Sounds like the carb has an issue....but, more importantly, does your oil smell of gasoline???

I'd be inclined to discourage your use of your vessel untl this is resolved....

My old boat did that all the darn time. Drove me nuts. I eventually rigged up an auxiliary electrical fuel pump before the mechanical pumps, with a momentary switch, to fill the carbs before start up.

If you already have electric pumps this is easy to do; just send power to the pumps with a momentary switch. If not, you can buy marine safe pumps and put them before your mechanical pumps. Then, by holding the switch down for a few seconds, the carb bowls will be full and away you go!

As an added bonus, it does wonders for increasing the life of starter motors and flywheel teeth.

Jeff

Ayuh,.... Rebuild the carbs again, it's been 13 years, 'n quadra-jets are known to leak down,...

Thanks for info guys . Will keep you posted