Next question- Quadrajet

[Pirate Lady]

Now that we solved my fuel gauge issue. Next brain teaser.
7.4 Quadrajet.
If boat sits for a week, have to pump the hell out of throttle while turning key.
If boat has run the previous day it starts right up next day with one pump of throttle.
Been like this since I bought. I thought all this time it was the choke but it’s not. The engine is just as cold after sitting one day as a week.
So before I get a lot of responses…
Quadrajet
Not fuel in ejection
Not Smart whatever system
Not any kind of MPI EFI whatever.
I am thinking the float bowl is draining after sitting a while and I have to do all this pumping to fill the float bowl before firing. Where as after one day it is still full.
Thoughts if this is possible and how to fix.

 

[Happy Hour IV]

Not going to say normal but certainly well known issue. Google Rochester Leakdown. Most if not all passages in the carb are drilled out. The access hole for the drill bit is then plugged with a "well plug". This tend to leak with age. There is a fix procedure. I also had other issues so I had mine rebuilt. This partially cured the issue. I think part of the remaining issue is now evaporation out the bowl vent. It does no good to pump it until the bowl gets some gas in it from cranking. So crank it a little bit then pump 2-3 times and your good. For a complete fix convert to electric pump. I had a mechanical pump fail from old age so figured it would be a good time to try electric. I installed a push button primer that bypasses the oil pressure safety lockout. This way I turn the ignition on (no cranking), push the button until the bowl is full. starts with just a quick turn of the key. If you can hear the pump the sound changes when the bowl fills and builds pressure against the float. I have fuel flows, I watch the analog flow (pegged dial) until it suddenly drops to 0. Or just live with it knowing you have lots of company.

 

[dwna1a]

Mine are the same way and you see this issue every year about this time. My Qjet guy says he think the fuel evaporates from the bowl after a shut down of over a day.

 

[Pirate Lady]

You guys are Great. I knew I wasn’t losing my mind over this ! Thanks for confirming I ain’t nuts!

 

[dvx216]

there plastic plugs in the bottom of the bowl that over time leak down the bowl plugs might need replaced

 

[Creekwood]

Not going to say normal but certainly well known issue. Google Rochester Leakdown. Most if not all passages in the carb are drilled out. The access hole for the drill bit is then plugged with a "well plug". This tend to leak with age. There is a fix procedure. I also had other issues so I had mine rebuilt. This partially cured the issue. I think part of the remaining issue is now evaporation out the bowl vent. It does no good to pump it until the bowl gets some gas in it from cranking. So crank it a little bit then pump 2-3 times and your good. For a complete fix convert to electric pump. I had a mechanical pump fail from old age so figured it would be a good time to try electric. I installed a push button primer that bypasses the oil pressure safety lockout. This way I turn the ignition on (no cranking), push the button until the bowl is full. starts with just a quick turn of the key. If you can hear the pump the sound changes when the bowl fills and builds pressure against the float. I have fuel flows, I watch the analog flow (pegged dial) until it suddenly drops to 0. Or just live with it knowing you have lots of company.

Its this issue^^^^
I am just used to it so its no big deal. On mine it takes about 3 or 4 days to leak down so it doesn't start without a few cranks. Before that, one throttle pump to set the choke and the engines fire right up. If its been more than 3 or 4 days, I just let it crank for about 3 or 4 seconds. Then two throttle pumps and they fire up.

 

[Pirate Lady]

Thanks again, much appreciated.

 

[Soulshine]

You guys are Great. I knew I wasn’t losing my mind over this ! Thanks for confirming I ain’t nuts!

Problem solved.

You're still nuts though.

 

[boatman37]

I have rebuilt about 100 -Jets back in my racing days in the early to mid 90's. I always took a file and roughed up the bottom of those fuel well plugs then applied some JB Weld to them. Don't goop it on too thick as it could interfere with the bowl/well in the throttle plate and not let it sit flush.

 

[mrsrobinson]

Had the exact same issue on the twin 7.4's on my 330. Finally came up with a pattern, I think it was two full throttle pumps and a half pump and they'd fire right up when cold.

 

[Nater Potater]

I wire-brush the tops of the well plugs and slather some JB Weld on them, but it's been said that they will eventually leak again. I haven't seen it... However, if you're so inclined, you can pull the old plugs and install the o-ringed variants. The advantage there is they can easily be pulled at a later date if/when you're into them for a fresh rebuild. That's probably the route I'll take with the twins on mine this summer.