7.4 Carburetor Engine, Will Not Start A Week Later.

My last two boats with Rochester Q-Jet carbs always required a few seconds of cranking before pumping the throttle to start. I had carbs on both boats rebuilt with new well plugs and the problem was still present. To this day, when I start my boat after a week or more of stiing, I crank for five seconds, pump three times and start, works for me.
 
SCORPIO said:
My last two boats with Rochester Q-Jet carbs always required a few seconds of cranking before pumping the throttle to start. I had carbs on both boats rebuilt with new well plugs and the problem was still present. To this day, when I start my boat after a week or more of stiing, I crank for five seconds, pump three times and start, works for me.
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X2 Carb are vented, gas evaporates period. Every Q-jet I've seen whether old or just properly rebuilt has the same symptoms. No big deal, just crank for 3-5 seconds, pump the throttle 2-3 time and the motor starts instantly. Only way to change it would be to install and electric fuel pump but I'm not convinced they are any more reliable than a mechanical pump.
 
I need to "prime" the carb too after setting for awhile. Usually turn it over a few times, stroke the throttle 2 times and start her up. Only time it took longer was when the points corroded or choke stuck.

You should have auto choke and breakerless distributor.
 
Sdarc, Thanks for the tip!
It's not a real big deal but it is somewhat annoying!
I will perhaps change out the carb when it comes time for a rebuild.

Jeff
 
If you read the original post, the man has had this boat since 2010, and this problem just started which kind of blows your evaporation theory out of the water. Rebuild it . leaky plugs, bad pump, sticky whatever, the problem will go away.
 
My carb is rebuilt and I still need to prime it after sitting for a couple weeks. I could crank the starter for a few minutes and it will start or I can save the starter, give it 2 pumps on the throttle and it starts instantly.

Mike I would go easy on the starting fluid. Too much and you could burn a piston or score a cylinder wall. Starting fluid will wash the oil film off the cylinder walls and may score them.
 
I have used a thin peace of cloth and sprayed through it to atomize the liquid a bit. Raw liquid going in can burn the piston. It's the vapor that ignites. In place of either use a small spritzer bottle with gas in it. Spray a little in the carb then get the bottle away from the carb before starting. Never spray while turning the engine over as a backfire or ignition spark may cause the gas or either to blow up.

If you use gas, do not spray through the filter. Gas will leave an oil residue that can catch fire. The oil residue is what helps lubricate the upper cylinder walls.

All of these methods are dangerous and only with great care would I try them.
 
Carb cleaner works well and is less volatile than starting fluid, you wont get the piston knock.
 
sdarc said:
These carbs do not have the well plugs. But somehow they do leak into the intake and then the combustion chamber. I had one do this on a Chevy ZZ4 crate engine. Hydraulic and broke the rod on start up in my driveway. Engine had stopped with a valve open and the fuel dumped in. Hit the key later and instant bang, bang, bang... My engine builder found a flooded chamber on a big block. I haven't figured out why these do this. been going Holley ever since.
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if you put a spacer with heat sinks under them it will reduce the issue
they are bad t boil the fuel bowl and spill out the bowl vents down the throat of the carb
 
Spacers do help. Unfortunately that wasn't the case with mine. Started the truck to move it 40' down the driveway. Went back about an hour later to move it back to it's original space and bang went the motor.
 
Does the crank/pump/start thing not work for your boat? I have never used starting fluid or anything else on a boat engine, too much risk of backfire IMO. If it won't pump up fuel using the crank/pump/start routine, then I suspect you have a bad fuel pump, because a good one should bring up sufficient fuel in a few seconds to fill the carbs and allow it to start normally.
 
SCORPIO said:
Does the crank/pump/start thing not work for your boat? I have never used starting fluid or anything else on a boat engine, too much risk of backfire IMO. If it won't pump up fuel using the crank/pump/start routine, then I suspect you have a bad fuel pump, because a good one should bring up sufficient fuel in a few seconds to fill the carbs and allow it to start normally.
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Did try it, but didn't work. Will try again when I need to start again.

MM
 
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