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454 mag carb idle too low in gear?
Chrisvr6
Member Posts: 166 ✭✭
Would you bump your idle mixture up a bit if the motor gets bogged and dies when put into gear (first detent on shifter)? Really only when its cold seems like
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Boat Name: King Kong
"Boat + Water = Fun"
Boat Name: King Kong
"Boat + Water = Fun"
Other than that or something similar, all I got left for you is improper plumbing on the four way stat neck/housing, or jammed open check balls allowing flow.
There are two types of chokes-- manual and automatic.
Manual chokes have to be adjusted by the operator from the helm. These were common in REALLY old cars.
Automatic chokes are, as the name implies, are automatic-- no operator intervention required. There are two types of automatic chokes, electric and divorced.
Electric-- When you turn the ignition key on, 12 volts is applied to the bi-metal coil inside the choke operator, this causes the choke to open over a set TIME period.
Divorced -- A bi-metal coil is contained in a little "can" mounted on the engine's intake manifold by the carb. As the engine warms up so does the bi-metal coil, thus causing the choke to open.
Chokes help cold engines start and run by making the fuel/air mixture rich, as the choke opens, the mixture leans out.
The mixture being rich will cause higher than usual fuel burn and can cause an engine to stumble when the throttle is advanced.
Don't try fixing a cooling problem by adjusting the carburetor.
Good luck
the risers aren't even warm when you run it?
man- you've got something going on that I bet some would love to recreate in their own engines!
Boat Name: King Kong
"Boat + Water = Fun"
first off, check that circulation pump bolted to the front of your engine. At this point I'm willing to bet you're running a high volume/high flow w/p... BBC's can push 100gpm at just off idle speeds (800rpm), a high flow can push in excess of 160gpm... that's a hella lot of flow.
now, you need that flow (being belt driven it increases with RPM to match up) up top, but you don't need it down low; or, you don't need as much as you're getting (whether it's a high flow or not)... so- how do you 'fix' this issue without having to remove the pump?
grab your pulley puller... we're going to under drive the thing!!! if that thing has a 7" pump wheel, put a 7.5" wheel on it... You'll need a longer belt, but, they (belt and pulley) aren't near as expensive as a water pump and installation. In my humble opinion, you'll want to only change the w/p pulley and go larger (to slow the impellers roll only) and not interfere with the alternator or the p/s pump.
there are calculators available online to determine the amount of revolutions dropped/added by over or under driving accessories. a nice side of this mod (if you choose to go this way)? Added ponies... you won't believe the amount of parasitic power loss that accessories rack costs you.. I'd guess off the cuff you'll add 10 ponies by adding a half inch of diameter.
that ought not happen no matter what.
the choke (carb'd) is good for two things- getting a cold engine running w/ residual fumes available in the runners, AND, keeping a cool engine from predetonation... predet is terrible on engines, obviously... a very rich mixture, however, is harder to ignite than a lean mixture, so it's less likely to detonate before spark is applied... a cold engine has parts (primary concern of the marriage between heads and block, and wrist pins of pistons) that expand at different rates, and therefor allow for wiggle.. a predet could really take advantage of this and blow a head gasket or break a wrist pin- so, these things run rich until they're warm. EFI does the same thing, but senses what to do and when instead of just using 'round about' margins.
anyway... stioch is air to fuel ratio is 14.7:1, which is the perfect blend. For performance, it's said that 13.9:1 is best, as it is considered that the fuel actually becomes a coolant before blowing, and it wards against predet again... also, it allows a margin of safety when you shut it down fast or an air obstruction is encountered.. perfect for economy is said to be 15.1:1... slightly lean.. a lean ratio (15.3:1+)is a highly volatile ratio ready to blow at any time under any influence, even such as compression alone... it's to be avoided.
your engine has a meter on the carb and the carb alone which alters air:fuel... you need to adjust that.. even at full choke you ought not be above 13:1 a/f... anything below that and you're washing the cylinders. You can't adjust for this unless the engine has reached full operating temperatures... if it's running rich enough to die, you're running in the 'wash' range of 12~13:1, because it flat won't run with more fuel present than 11 parts air... it'll flood out...
rich runs cooler... lean runs warmer...
when is the last time you serviced your carb? when the jets clog, they drip... when they drip, they hang around longer and combine with the next gulp of whats 'sposed to be around 14.5:1 a/f in the runners, which now becomes 11:1 or worse because of the liquid fuel...
I'd pull that carb and clean it. tune jets. clean the throat and the passages, and all the pins. Running as rich as you are, there has to be a cause beyond engine temperature... and one thing to consider using a carb'd engine- you may descending amounts of fuel present in the cylinders from the cylinders closest the carb to the ones furthest away, which means some cylinders running rich, some okay, and some dangerously lean...