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454 mag carb idle too low in gear?

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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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    I'd check the autochoke first... They are notorious for freezing up/jamming on themselves.  
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    Chrisvr6Chrisvr6 Member Posts: 166 ✭✭
    Its a mechanical choke. 
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    Chrisvr6Chrisvr6 Member Posts: 166 ✭✭
    Still having an overcooling issue also. Will not warm up for anything. Its probably causing it to run rich and bog. I figured it'd be easier to bump up the idle since i can't figure out the overcooling issue. I hear some people run without stats anyway. 
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    MarkBMarkB Member Posts: 3,967 ✭✭✭✭✭
    Chris, I assume you replaced your T-stat?

    Boat Name: King Kong

    "Boat + Water = Fun"

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    Chrisvr6Chrisvr6 Member Posts: 166 ✭✭
    Yep. Twice. Tested in boiling water too. Its so crazy. 
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    MarkBMarkB Member Posts: 3,967 ✭✭✭✭✭
    How do you know you have an overcooling issue? Temp guage? Is it working?  Could be the temperature sending unit.

    Boat Name: King Kong

    "Boat + Water = Fun"

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    Chrisvr6Chrisvr6 Member Posts: 166 ✭✭
    Gauge comes up when i starve it of water on muffs and keep hatch closed to keep heat in. After shut down it creeps up as well once cold water stops flowing. 
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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    Do you by chance have a high volume/high flow circulation pump on that thing?  They were durn popular for trucks running BBC's... I could see somebody tossing one on there thinking they're doing good, but creating your issue by mistake instead.  They usually have an extended cone like nose on them with lil ribs that look something like cooling fins.  It'll be obvious because it'll also have a shaft extending through the housing, which is what the clutch fan would attach to if'n it were in a automobile. 

    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. 
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    blutobluto Member Posts: 25 ✭✭

        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

         

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    Chrisvr6Chrisvr6 Member Posts: 166 ✭✭
    Well all the hoses are cool to touch even after a hi-speed run on lake michigan. Will be taking apart the thermostat housing to see whats going on. Will i sink my boat doing this in the water? 
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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    naw, man.. you're not gonna take on water while doing this unless you draw straight from a thru-hull to feed it... and I doubt you do. 

    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! :smile: 


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    MarkBMarkB Member Posts: 3,967 ✭✭✭✭✭
    edited June 2015
    Just replaced my t stat on my 350 mag b3 and no water came in.

    Boat Name: King Kong

    "Boat + Water = Fun"

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    Chrisvr6Chrisvr6 Member Posts: 166 ✭✭
    naw, man.. you're not gonna take on water while doing this unless you draw straight from a thru-hull to feed it... and I doubt you do. 

    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! :smile: 


    You can have what i got going by removing your stat. Yup everything is cool to touch. You'd love it. Dying when leaving slip its running so rich. Soot across the whole rear. If i crossed the inlet lines, I'm going to sink it for sure if i have to uncross those. Lol
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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    you know what?  After thinking about this a bit, I got a solution for you.... 

    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. 
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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    re: dying when leaving the slip due to rich mixture:

    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...  
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    Chrisvr6Chrisvr6 Member Posts: 166 ✭✭
    Wow. It ran perfectly fine before i messed with the thermostat and impeller though. 
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    howardramshowardrams Member Posts: 223 ✭✭✭
    So, is your carb a quadrajet?  Is it stock?  Sounds like a choke issue or dirt in the main metering jet if it's putting out that much soot and smoke.  Running cold seems a separate issue altogether, likely caused by the thermostat being by-passed by a hose on wrong? 
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    Chrisvr6Chrisvr6 Member Posts: 166 ✭✭
    Its stock. Runs great other than a little bog in idle(first detent on shifter) when i leave slip at first. When i come back after a run and parking (at low speeds, first detent) no bogging but still rich because temperature never comes up. 
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    howardramshowardrams Member Posts: 223 ✭✭✭
    Make sure you try the marine thermostat Mercruiser specifies, not just a generic marked with the same temp.  The speed they open and close can vary a lot.
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    Chrisvr6Chrisvr6 Member Posts: 166 ✭✭
    So, who never puts back the thermostat after running antifreeze through the motor for winterization. This ****. 
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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    Now that's awesome.... Glad you found it!!!!  I've done worse... 
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