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Holley carb kit, adjust float level? Help!

GaryWilkinsonGaryWilkinson Posts: 356 Solid Baller
edited June 2020 in Boat Talk

My 95 Nautique was running rough-ish at the end of last year and decided to do a carb kit. Got it all done and started it up to what sounded like a Topfuel dragster on the staging line it was that rough. Couldn’t hold and idle less than 1500 rpm and it was loud and tons of grey smoke and burnt oil coming out. I figured it was the fogging oil (hopefully) shut it down and talked to mechanic who said did you set the float levels?

Can’t find those screws on my model of carb.

Any ideas?

I need to ski back to the handle obviously.


  • JetsetrJetsetr Posts: 466 ★★★Triple Panda Award Recipient ★★★
    The Holley 4160’s either have non adjustable float bowls or adjustable...
    I’m THINKING you have a stuck float/needle and seat or two. Tap the float bowl with a hammer (seriously) sometimes that’s enough.

    Otherwise you need to remove the bowl and slightly bend the float tab to lower the float.
    Pull the air cleaner off and see which side is dumping the fuel back and we will go from there.
  • Orlando76Orlando76 Posts: 1,294 ★★★Triple Panda Award Recipient ★★★
    Marine Holleys aren’t externally adjustable.
  • JetsetrJetsetr Posts: 466 ★★★Triple Panda Award Recipient ★★★
    I swapped the adjustable bowls onto my 4160. Pretty sure your correct Orlando76.
  • GaryWilkinsonGaryWilkinson Posts: 356 Solid Baller
    @Jetsetr @Orlando76 agree, no external adjustments.
    The gas is FLOWING from the primary side. Nothing (yet) from the secondaries.

    Any documents / videos you could point me to would be great. Haven’t found anything yet.

    Is it as simple as taking off the 4 bolts that hold each side on? Gotta be careful of those transfer tubes that crossover to the other side.

    Any info is really appreciated. Thanks fellas.

    I need to ski back to the handle obviously.
  • Orlando76Orlando76 Posts: 1,294 ★★★Triple Panda Award Recipient ★★★
    edited June 2020
    Not to be a smartass but YouTube and google. Keep in mind it’s a MARINE 4160. Auto 4160 has external adjustable floats. Open it up and make sure needle is seating properly. Does your engine sit level? Some inboards don’t sit level so primary float typically overflows and secondary starves.

    Most carb guys will disagree with me but next time just buy a brand new marine 4160 from Summit calibrated for the Ford or Chevy. Bolt it on, adjust idle and voila it’s good. You’ll always be happier with a new carb vs a rebuild.

    Edit-Nevermind I re-read thread. 95 Nautiques sit level.

    We know your carb is jacked now, but back to last seasons issue, what ignition system are you running on that boat?
  • ReallyGottaSkiReallyGottaSki Posts: 218 Baller
    Well not exclusively..
    Indeed most marine holleys have no external adjustment but its not hard and fast.
    But what you shouldn't see are any bowl plugs for setting the level.
    for instance list 9022


    Holley Blue bowl gaskets let you take the bowl off a couple times with no damage and

    Yeah something is amiss with the primary float/neede/seat. go in there and chech for gunk. If trash in there, investigate how it got past the filter.

    A little oil on the xfer tube orings help with leak-free assembly. then roll and push the xfer tube around fore/aft and seat the orings well after assembly.
  • BraceMakerBraceMaker Posts: 4,548 Mega Baller
    @Orlando76 - I don't disagree - but you can send them to a few people for tuning for less than half price and it works great. In some ways this also helps to get the correct power valve etc.

    In future however I do not recommend doing a carb rebuild before checking on the ignition system. As often rough running is poor ignition while a strong ignition system will fire off some very poor carb settings.
  • JetsetrJetsetr Posts: 466 ★★★Triple Panda Award Recipient ★★★
    edited June 2020
    @GaryWilkinson remove the 4 bolts/screws in the corner of the float bowl. Also remove the fuel line (and use the correct wrenches or fuel line wrenches so you don’t round off the nut). Remove the fuel line FIRST. You can do all of this with the carb still on the engine, but you will need to catch the fuel in the bowl. Not that much, but enough to make a mess and fire hazard.

    SAVE yourself a bunch of trouble and buy some blue float bowl gaskets and transfer tube O rings first! Nothing more frustrating than to have fixed the problem and and have the transfer tube leaking fuel and ya have to take it apart agin. Just replace them when the bowl is off, and make sure they’re not rolled and seated properly. I use a touch of a product called “fuel lube” but a touch of grease works well too, it lets them move a bit while installing. As mentioned the blue float bowl gaskets can be reused a few times. I’m guessing the needle is stuck wide open for some reason (junk, or hung up) or you have a bad float. A bad float will sink and keep the needle open all the time.

    Where are you located???? If close I will fix it for you if it’s still giving you trouble.

    These carbs are REALLY simple...
    I have a 4160 on the shelve here and will take some pics of the internals for you...

    @Orlando76 I’m really not into throwing $650-750 away on a new carb to fix a really simple problem, and as someone who grew up with nothing I always had to at least TRY to repair stuff.

    Feel free to PM and I can give you my phone number if you’re still having trouble.

  • 2Valve2Valve Posts: 368 Crazy Baller
    I rebuilt one of these for a friend's boat some years ago and we spent a great deal of time getting the floats adjusted perfectly. It was a nice improvement in running and idle. People don't realize how critical float adjustment is on any engine.
  • Orlando76Orlando76 Posts: 1,294 ★★★Triple Panda Award Recipient ★★★
    edited June 2020
    @Jetsetr I partly agree with you, but....No disrespect to Gary but I feel no matter what he’s going to be into this for $600 IF he doesn’t solve this issue himself. I feel the mechanic he talked to isn’t a marine mechanic. As the mechanic should’ve said “how’s the ignition, and btw marine 4160’s (and all post 1972 marine holleys as far as I know) don’t have external float adjustments?” Now he’s going to have frustration and downtime to factor in. Is he in Canada? What’s that like a 5 day season? I like to fix and figure things out myself. I also know that if I don’t fix and make that carb perfect in 1 R&R, once I factor in frustration and downtime, I could have easily gone to work and made that $699 for a brand new carb with minimal frustration.
  • JetsetrJetsetr Posts: 466 ★★★Triple Panda Award Recipient ★★★
    @Orlando76 I totally understand your point/position....
  • ALPJrALPJr Posts: 2,382 Mega Baller
    SkiDim. I got a new 4160 from them for our Prostar. I was surprised how easy of a job the replacement was and how much better the motor ran.
  • MDB1056MDB1056 Posts: 581 Crazy Baller
    Carbs are actually pretty easy and inexpensive to rebuild, and plenty of places for high quality kits and instructions. I highly recommend doing it yourself vs buying a whole new carb. That's a lot of gas money......
  • JetsetrJetsetr Posts: 466 ★★★Triple Panda Award Recipient ★★★
    If it was a Rochester Quadrajet I would tell you shit can it and get a Holley! Have a Edelbrock (Carter) 1409 on the SBC in the Malibu. It sat for 4+ years and I just changed the accelerator pump and it runs perfect (another simple carb to work on)...
  • WayneWayne Posts: 551 Solid Baller
    @GaryWilkinson when you rebuilt the carburetor did you compare the old gaskets to the new ones in the rebuild kit? Holly had a few gasket designs and the rebuild kits usually include a few different ones that look similar. Every little hole matters.

    Having non adjustable float bowls is not a big deal. If the carb has plastic floats you can’t adjust float level. You need the metal floats so you can bend the float arm. Typically if you hold a float bowl upside down and look at the flat part on the float. If the flat part of the float is parallel to the inside wall of the float bowl your good to go.

    For how much crap was on the ground and your description of the idle it would have to be running very rich. The little 180 degree tubes on the top of the carb are the bowl vents. Was any fuel coming out of them? If a float is stuck causing the needle and seat to be open, fuel will some times come out of the bowl vent tubes.

    The behavior you are describing can also be from a blown or leaking power valve.

    I highly recommend getting reusable bowl and metering block gaskets. Summit Racing or Jegs carries kits from Moroso which are much better than the blue Holly gaskets. You can also “make” the standard gaskets into reusable by using rubbing alcohol to remove the glue and then spray the gaskets with Pam cooking spray. However I wouldn’t recommend doing that unless you have some spare gaskets to learn on.

    Not sure where you live, if you were local I would help you go through the carb again to be sure there are no issues with it.
  • WayneWayne Posts: 551 Solid Baller
    Should have made a clarification on the plastic floats, they are non-adjustable unless you have the threaded needle and seat assembly that was pictured. Also the plastic covering the needle and seat assembly slides out of the bowl if needed.

    The plastic floats can also deteriorate over time and become “water logged” with fuel so the don’t float properly. I’ve never seen that personally but it’s stated in all of the Holly performance books I have.
  • MDB1056MDB1056 Posts: 581 Crazy Baller
    @Jetsetr have to disagree on Quadrajet. Great carb, super easy to work on and rebuild, easier than Holly. Like all brands they all have followings. I know many who label Qjets as one of the best ever made. I’m a fan of both.
  • JetsetrJetsetr Posts: 466 ★★★Triple Panda Award Recipient ★★★
    @Wayne The pics of the internal float bowl assembly was from my 4160 with the adjustable floats. Was just showing the OP what’s inside. If I remember the non adjustable floats are a bit different, with a “arm” that you bend to adjust the level. Great tips on the power valve and vent tubes. That was a LOT of fuel to make a mess like that!

    @MDB1056 Never had much luck with Q-Jets...lot of people do REALLY like them though...
  • GaryWilkinsonGaryWilkinson Posts: 356 Solid Baller
    @Jetsetr @Orlando76 Thanks so much for the help guys. Truly great of you to take the time.

    Few points: mechanic is a marine engine mechanic, that’s where it is now but he won’t get to it for probably 10 days. I trust him, knows his stuff. BUT I may go there this weekend and at least take some pics for myself and this thread.

    I wasn’t there when my cousin did the carb kit. He knows engines pretty well but yes, could have made an error of course.

    Ignition is stock, plugs, points etc. Tried a few years back to use upgraded wires ((Accell?) and ran poorly, went back to stock wires.

    When the idle and general performance gradually deteriorated last season I admit I didn’t think of ignition components. Probably should have swapped out wires, point, condenser first instead of this world of hurt I find myself in. And yes, our season is very short, 2 1/2 - 3 months, most of it in wetsuits.

    Ya Dave, you have to be really careful on the fuel line nuts. A perfect fitting wrench is the only way to go. In fact I’m going to check that it wasn’t cross threaded! (gasp)

    The minimum will be to go to the boat in my mechanics years and take some pics with the bowls off. Hopefully I won’t need new gaskets to do just that.

    What do you think about switching the bowls to external adjustment capability?

    Thanks again for the help and tic, tic, tic. I can hear the season moving along goddammit.

    I need to ski back to the handle obviously.
  • JetsetrJetsetr Posts: 466 ★★★Triple Panda Award Recipient ★★★
    I swapped fixed to adjustable on a MC S&S...made getting float height set a lot easier with the non level carb in the earlier boats. We had an issue with fuel just dripping thru the Venturi causing a little bit rich condition @ idle, and after a while the engine would load up. However, removing the float bowl really isn’t that big of a deal for fine tuning the float. Like Wayne said if you turn it upside down and the float is level that’s going to get you pretty close. I think you have something stuck in the needle or a bad float for as much fuel that was going thru.
  • JetsetrJetsetr Posts: 466 ★★★Triple Panda Award Recipient ★★★
    Didn’t forget the needle???
  • MDB1056MDB1056 Posts: 581 Crazy Baller
    @GaryWilkinson - Can't still have points ignition as noted earlier post you said "point". Assuming it's electronic ignition since a 95. Really hate to see you without for another 2+ weeks. I'd recommend you put the carb on the workbench (or kitchen table) and take apart and reassemble in an afternoon and be back on the water. It's really not scary at all....
  • GaryWilkinsonGaryWilkinson Posts: 356 Solid Baller
    @MDB1056 ya believe it or not, it’s points ignition. Distributor cap, rotor, condenser etc. It’s all there.

    I’m going to have another go at it this weekend.

    Found this on the web also.
    This with your collective advice above Will get me going hopefully.

    Two methods of float adjustment are provided for with Holley
    performance carburetors depending on the style of float bowl
    and needle and seat assembly employed. They are the inter-
    nal (dry) setting and the external (wet) setting. The internal
    float adjustment is accomplished with the fuel bowl off the
    carburetor. With “internally adjustable” needle and seats, the
    fuel bowl is inverted and the float tang, or tab, is adjusted to
    the point where the float surface is parallel to the fuel bowl
    surface, just underneath. An initial dry setting can also be
    accomplished with “externally adjustable” needle and seats.
    To achieve this, invert the fuel bowl and turn the adjusting nut
    until the float surface lies parallel to the fuel bowl casting
    surface underneath.
    Another, more accurate adjustment can be made with the
    side hung style float if measuring gauges, such as drill bits,
    are available. Here, with the fuel bowl inverted, the primary
    float can be adjusted to the point where there is a 7/64" gap
    between the “toe” of the float and the bottom of the fuel bowl
    surface underneath. The float “toe” is the part of the float fur-
    thest from where the arm is attached. The secondary float
    can be adjusted to the point where there is a 13/64" gap
    between the “heel” of the float and the bottom of the fuel
    bowl surface underneath. The float “heel” is the part of the
    float closest to the point where the arm is attached.
    A “wet” level float adjustment can be performed on either the
    side or center hung floats, if the fuel bowls have provision for
    the externally adjustable needle and seats. This adjustment is
    made as follows. Start the vehicle up and move it out of the
    garage and into an open area where plenty of fresh ventila-
    tion is available. Allow the idle to stabilize. Turn the engine
    off and remove the sight plug from the primary fuel bowl to
    inspect the fuel level. If it’s been determined that adjustment is
    required use a large screw driver to crack loose the lock
    screw. With a 5/8" open-end wrench turn the adjusting nut
    clockwise to lower the float level.
    Conversely, turn the adjusting nut counter-clockwise to raise
    the float level. Tighten the lock screw. Restart the vehicle and
    let the engine idle stabilize. Shut the engine off. Remove the
    sight plug to reinspect the fuel level. The fuel level should sta-
    bilize at just below the level of the fuel bowl sight plug hole.
    The Duracon float rides higher on the fuel than either the
    brass or nitrophyl float and, therefore, a higher setting is in
    order. A Duracon float, set at the same level as either a brass
    or nitrophyl float, would make the carburetor run leaner,
    everything else being equal. This is because there would be
    less fuel available in the fuel bowl. The Duracon float setting
    must be higher to compensate for this condition.
    Dry Setting for Duracon Center Hung Float:
    The primary side setting is .3125" (5/16"), measured with
    the fuel bowl inverted, at the middle of the float. The second-
    ary side setting is .3750" (3/8"), measured with the fuel
    bowl inverted, at the middle of the float (back side).
    Dry Setting for Duracon Side Hung Float:
    The primary side setting is .2188" (7/32"), measured with
    the fuel bowl inverted, at the toe of the float. The secondary
    side setting is .3125" (5/16"), measured with the fuel bowl
    inverted, at the toe of the float.
    Wet Setting for Duracon Float:
    Refer to “Wet Float Setting”, discussed previously.
    I need to ski back to the handle obviously.
  • BraceMakerBraceMaker Posts: 4,548 Mega Baller
    @GaryWilkinson - WILD I had thought that starting in 91 SN had gone to those funky electronic distributors protec?
  • Orlando76Orlando76 Posts: 1,294 ★★★Triple Panda Award Recipient ★★★
    @BraceMaker Protec was 92-94. Possibly 91. Then the went back to conventional distributors after that.
  • BraceMakerBraceMaker Posts: 4,548 Mega Baller
    @Orlando76 and by conventional - breaker ignitions?
  • Orlando76Orlando76 Posts: 1,294 ★★★Triple Panda Award Recipient ★★★
    Conventional: While this is called a “conventional” ignition system, it’s something of a misnomer. These are not used on modern cars, at least not in the US. This is an older style of ignition system that uses points, a distributor, and an external coil. They’re high-maintenance, but easily fixed and pretty cheap. Service intervals ranged from every 5,000 to 10,000 miles.

    Electronic: An electronic ignition is a modification on the conventional system, and you’ll find these in widespread use today, although distributor-less systems are now becoming more common. In an electronic system, you still have a distributor, but the points have been replaced with a pickup coil, and there’s an electronic ignition control module. These are far less likely to breakdown than conventional systems, and provide very reliable operation. Service intervals on these types of systems are generally recommended every 25,000 miles or so.

  • BraceMakerBraceMaker Posts: 4,548 Mega Baller
    Ok we're on the same page I usually refer to electronic systems that replace a points set up with a hall effect sensor or similar while still in a mechanical advance distributor as a "breakerless ignition" as opposed to an electronic ignition and haven't referred to a points as conventional for the same reason as referenced I'm not sure the guy who changes my oil knows how to use a feeler gauge or dwell meter.

    I use that nomenclature as I do not love breakerless conversions of conventional distributors but do like HEI conversions.
  • Orlando76Orlando76 Posts: 1,294 ★★★Triple Panda Award Recipient ★★★
    They all have improved. Module failures on conversion kits have gone down from what I’ve gathered tremendously... but, It’s hard to beat a clean 1 wire installation of a DUI. For some reason when you throw a ballast resistor in the equation people go brain dead.

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