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Thread: Strange Holley Carb Problem?

  1. #1
    zgoo
    I have a 1979 Glastron CV23 w/460 Jet. The boat is 100% stock with about 75 hours on it since new, was in storage for a lot of years. I buy the boat and change out the 12 year old gas, rebuild the Holley 650 Vac second carb. The inside and outside of the carb still looked new, but I still put a kit in it. I took the boat out and it ran great except for strange problem with the idle. When I would take the RPM's up to when the secondary kicked in and then return to and idle the rpm's will stay about 2000. I then removed the throddle cable and the idle stayed the same so it's in the carb. I checked the idle stop screw and it was closed on it's stop. Now here is where it gets strange, if I just turn the motor off and restart with out doing any thing else, it idles normal. It would seem that the secondary butter flies are sticking or some how the vac pull off is still pulling vacuum?
    The second problem is I was running back to the ramp at the end of the day and around 3000 rpm and it acted like I was running out of gas, the engine died, I restarted, run a few minutes longer, then did the same thing, so I restarted again then just idled back to the ramp area which took about 30 min. Do you guys think that since the fuel pump is about 30 years old that it's going out or could it be a plugged pickup in the tank. I was thinking that I should replace the mach. pump with an electric one? If I go electric, which pump would be best and how are they wired into the boat? Thanks for any and all help!!!!

  2. #2
    speedymopars
    I have a 1979 Glastron CV23 w/460 Jet. The boat is 100% stock with about 75 hours on it since new, was in storage for a lot of years. I buy the boat and change out the 12 year old gas, rebuild the Holley 650 Vac second carb. The inside and outside of the carb still looked new, but I still put a kit in it. I took the boat out and it ran great except for strange problem with the idle. When I would take the RPM's up to when the secondary kicked in and then return to and idle the rpm's will stay about 2000. I then removed the throddle cable and the idle stayed the same so it's in the carb. I checked the idle stop screw and it was closed on it's stop. Now here is where it gets strange, if I just turn the motor off and restart with out doing any thing else, it idles normal. It would seem that the secondary butter flies are sticking or some how the vac pull off is still pulling vacuum?
    The second problem is I was run back to the ramp at the end of the day and around 3000 rpm and it acted like I was running out of gas, the engine died, I restarted, run a few minutes longer, then did the same thing, so I restarted again then just idled back to the ramp area which took about 30 min. Do you guys think that since the fuel pump is about 30 years old that it's going out or could it be a plugged pickup in the tank. I was thinking that I should replace the mach. pump with an electric one? If I go electric, which pump would be best and how are they wired into the boat? Thanks for any and all help!!!!
    There is an idle screw on the secondaries, not readily accessable and it has it's own built in return spring. The fact that it idles when it has been sitting, says that the spring is probably dirty or has come off the little pin that holds it in place (and that you don't need to touch the secondary idle speed setting). Take some carb cleaner and find the secodary spring. It is on the opposite side of the throttle cable on the secondary shaft.
    Holley secondaries are not directly linked, and are more designed to open positively rather than close 100% - the spring is supposed to take care of that. After cleaning it, make sure it is clipped and providing closing force.
    I would change the filter first, it does sound like the carb is running out of fuel, or you were experiancing vapor lock (uncommon on a boat). Mechnaical pumps like to suck, electrics like to push - so if you get an electric get it as close to the tank as you can. I personally like the Mallory comp 140, it is quiet and flows enough for 800 HP. Obviously it is inherently more dangerous, as if something happens you will have fuel spilling out into your hull. This is the reason I will only run a mech on a boat while all of my racecars get nothing but electrics.
    To make it a little safer, have a manual switch to be able to shut it off, and get a remote fuel pressure gauge. That way if you see something wierd you can kill it and check it out beofre you have 10 gallons of fuel sitting under you.
    The other danger is that if you stick float in the carb - with a mechanical the engine will die and the fuel will stop as the carb venturi fills with gas and then overflows. With an electric, it just keeps pumping fuel out and onto the engine. Really dangerous normally, deadly if you have a cover.

  3. #3
    ck7684
    That mech pump is most likely shot after sitting for so long. Unless you really need a hi volume electric, I'd stick with a mech one...I'd also replace all the fuel lines etc. if they are rubber. You dont need any deteriorated bits coming loose and clogging any of your new stuff...

  4. #4
    napabob
    1. I filled up the tanks, and then I lowered the bow of the boat. I removed all of the gas and then let the tanks ‘dry out’ by leaving the gas caps open with some screen door material over them to prevent anything from falling into the open gas fillers, let dry for a day. With a flash light designed to prevent sparks (Used by firefighters) I managed to locate and remove debris from my tanks that had settled close to the front of both tanks!
    2. Install UL/USCG approved anti siphon valves at both tanks.
    3. Install UL/USCG approved fuel filter with water separator.
    4. Install UL/USCG approved marine gas shut off valves.
    5. Install UL/USCG approved marine mechanical fuel pump or electrical fuel pump.
    6. Install an ABC fire extinguisher (I have two at the bulkhead).
    7. Inspect/replace all gas fuel lines and connectors.
    8. Inspect/replace marine carburetor inlet fuel filter(s).
    9. Install a UL/USCG approve bilge blower if boat is equipped with engine cover.
    I use a Holley 750 CFM with vacuum secondary and when I installed it new it was missing one inlet fuel filter at the marine carburetor. Top it off with a UL/USCG approved flame arrestor, it is designed to work with the mechanical fuel pump.

  5. #5
    Moneypitt
    If you choose to go electric find an early Vega oil sender. It is also the power supply to the in tank fuel pump. Wire your fuel pump power thru it, no oil pressure, no fuel...........If you feel the problem may be in the fuel tank(s), plumb in a remote 5 gal can to your existing pump directly. If the problem goes away you know where to look, the tank(s), if not look in the other direction, the pump................MP

  6. #6
    zgoo
    I replaced all the fuel and water lines so that shouldn't be a problem. The fuel pump has a small fuel filter built into the pump. There is a little cup that has a clamp that holds it on the bottom of the fuel pump, and a small replaceable filter. I did replace the filter before I went out that day. When it started to run bad I removed the filter cup and there was clean gas in it. Where could I find the replacement pump like this one? Also what is the chance that there is a check ball in the pickup or a plugged pickup?

  7. #7
    zgoo
    I just went out and removed the pickup tube elbow with the check valve that goes into the tank and found in the bend of the elbow was plugged with crud and rust scale. I removed the check valve and clean it and the elbow out. There was a little screen in the top of the pickup tube and I removed it and cleaned it. I pushed a clear 5' hose in the top of the pickup tube hole and sucked up clean gas, there was no crud in it. So it looks like the fuel pump is fine.
    On the secondary problem, I pushed up on the vacuum rod and let go of it and the secondary throddle stayed open just a little. Where is the spring on the secondaries located?

  8. #8
    ol guy
    Sounds like you got the fuel disrtribution problem handled with plug in line. High idle problem is most likely the baseplate. Secodary throttle shaft is not returning easily. In other words, sitting for along time corrosion and such has made the secondary throttle plates hang slightly and creating a bind. Disconnect the vacuum can and check the ease of movement of the shaft by hand. If it does not return completely on its own bingo. Also vacuum opens it and does not return it. But shutting off the motor relieves any vacuum and it may come to rest at that point.

  9. #9
    Mr. Crusader 83
    Replace the fuel pump with a Holley Mech. My boat had the same problem.

  10. #10
    speedymopars
    On the secondary problem, I pushed up on the vacuum rod and let go of it and the secondary throddle stayed open just a little. Where is the spring on the secondaries located?
    There are two shafts that run through the carb. One is directly connected to the throttle cable, and moves when the throttle opened. The throttle plates are connected to this shaft.
    OK, so now you know what the primary throttle shaft is.
    The secondary shaft is the same thing, but connected to the secondaries, including the vaccum canister that you were playing with.
    Look on that shaft - there should be a spring wrapped around the shaft. That is the one I'm talking about.

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