-
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!!!!
-
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.
-
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...
-
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.
-
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
-
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?
-
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?
-
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.
-
Replace the fuel pump with a Holley Mech. My boat had the same problem.
-
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.
-
Is the spring on the left or right side?
-
You need to pull your tanks out and completely flush. You can use tide soap to flush tanks. Replace all your fuel lines, filters, etc. I know you said you have new filters youll need new one's again. Also you should replace the fuel pump also just a stock mech. If you don't do all these things these problems will plague you for every. I know because I bought a boat that had sat for years with gas in it. The gas turns to cystals in your tanks.
-
Hey ZGOO. The secondary return spring on a vacuum secondary carb is in the vacuum can. If your'e gas is clean in the filter, or sight glass most likely your'e filters are doing the job. NOW if the secondary butter-fly shaft needed to be pushed down to get fully closed you found the problem. If at all possible do not remove the butter-flies, as realignment to proper closure is a bitch. I would advise lube and move till it seats automatically on its own. And if you pull the vacuum can on the right side of the carb look at the color of the spring, this identifies the amount of vacuum it takes to open the secondaries. A silver spring will open long before a purple or green will. NOW carb tuning trick. At W.O.T. {wide open throttle } manifold is at zero vacuum and as the motor comes to grips with the amount of feul absorbed vacuum will again incress thus again creating vacuum and at this point the spring comes into play. It will then open secondary floww to feed the starving bitch. And by the way a 650CFM carb is aliitle small for a 460 ford.
-
Well taking out the tank to clean is not going to happen due to it being under the floor with no way of removing it. I did look in side of it and it looks pretty clean, so I will have to take my chances. The plugged elbow had the crude in the tight turn as it went into the check valve and it was rough water when it happened and some of the crude came loose and drop about and 1" down the pickup tube into the little cup screen sitting in the top of the tube, so the crude was swirling around in this little area until it cut the fuel flow down. So that should fix that. Now the carb.....
I will remove the vac. can and check it. I do know the when I had the carb apart that the shafts turn free with no sticking. The boat is such low hours that the carb is like new. But I did push up on the vac. can rod and the sec. did not close all the way. Could the spring be weak in the vac. can? Also, the linkage on the primary side that has a rod from the primary to the secondary is a short bent rod, with the primary closed how louse should that rod be?
The 650 Holley is the stock carb that came with the boat, if you guys could see this boat, the condition would blow you away. For a nearly 30 year old boat it is amazing to see how many people commnet on it. I was docked next to a new 38' Fountain and and more people were commenting about the Glastron. I even had people in other boats and skis come over to where I was floating down the river to say that was a cool boat! :D That never happened in my Chaparral. What would a bigger carb do for this engine?
-
The spring in the vac can should be very light to ease the opening of your'e secondaries and reseat the secondary butterflies when you come off throttle. But this not going to happen if the baseplate shafts are hanging up. When a boat sits for awhile all may seem clean on the outside but you never know what monsters are growing in tight spaces. Just work with them with some carb sray and then wd40 and they will operate smooth once again. The linkage on primary to secondary should wiggle when both are closed. 650 okay but 750 vacuum secondary like an old 3310 would bump the topend rpm on a jet boat assuming water jacket exhaust and stock motor.
-
What would a bigger carb do for this engine?
I looked at other CFM selection charts, but this might help you. It is for automobiles.
http://www.buicks.net/shop/reference/carb_cfm.htm
-
Could be as simple as a backwards gasket. Did ya check?
-
Hey ZGOO. The secondary return spring on a vacuum secondary carb is in the vacuum can.
dammit I hate getting old. Yes, the spring is only on mech secondary carbs. I coulda swore it was on both, but a quick check of my inventory says no. Only mech secondary carbs have the spring. Seeing as how the vac canister has a big freeking (and tunable!) spring inside, it makes sense. Duh.
I've only been doing this for 25 years. I feel smart at the moment. :rolleyes:
I would say you need at *least* 750 CFM with a single plane, 800 CFM with a dual plane to get max RPM.
-
Here is an update on this problem.
I replaced the rubber vac. part and check it to make sure that it will hold vacuum. The check ball is in the right hole and the spring was marked with a yellow paint. I checked the sec. shaft and it is free and smooth. I then took the boat out and it ran fine but did the same thing after a full rpm run to get the sec. open, it will still not idle below 2,000. The primaries are closed and on the idle stop but the sec. are open enough to keep the idle up at 2,000. So I removed the sec. vac. can and check to make sure that the vacuum ports to both the sec. and primary sides were clear, and they were clear. It's acting like there is too much vac at idle and keeps the shaft open, but that's impossible.
One thing that someone might be able to answer is the base gasket on the manifold to carb mount. there is a thick gasket that is all open between the sec. and primary sides, is this normal or is the carb suppose to have the sec. and primaries seperated from the carb to the manifold?
I rebent the linkage rod on the primary side that goes to the sec. shaft and made it tighter so that when the primary closes it will pull the sec. closed as well, is this a good ideal?
Guys, I'm totally stumped on this one.......:confused:
Dan
-
does it have a choke? if so, have you checked to make sure it's not sticking a little?
-
Steve,
Yes it has a choke, but it's open and doesn't have a fast idle cam for the choke.
Dan
-
Some how I'm think it is tied to vacuum. If I pull back from full thoddle and it stays at 2,000 rpm and I do nothing but shut the engine off and trun the key to restart it wil idle at 900rpm. This driving me crazy!!!
-
Dan,
The reason I asked about the choke is sometimes it can get stuck just enough to speed up the airflow in the primaries which will open the secondaries. Holley vac sec carbs work off venturi vacuum in the primaries and not manifold vacuum.
-
-
Hey zgoo, assuming you checked the butter-fly movement for returning back to seat and all is ok. Here is another thought, check the distributor and make sure the advance weights are returning to initial timing. You say after shut down and refire it idles fine. could be enough to alow the timing to come back and allow the motor to retard and be nice. Kind of off the wall but it does happen, ie: 12 degrees at idle 36 degrees at wot if it sticks whats the rpm at idle going to do?
-
Hey zgoo, assuming you checked the butter-fly movement for returning back to seat and all is ok. Here is another thought, check the distributor and make sure the advance weights are returning to initial timing. You say after shut down and refire it idles fine. could be enough to alow the timing to come back and allow the motor to retard and be nice. Kind of off the wall but it does happen, ie: 12 degrees at idle 36 degrees at wot if it sticks whats the rpm at idle going to do?
-
Well to day I spoke with the orignal owner of the boat, he purchased the boat new in 1979 and only used it about 10 hours the first two years, then put in his garage. :D The boat is all orignal so to my ???
When I pulled the carb the carb mount gasket was about 1/4" thick and all open between the pri and sec areas, is this normal?
I have not check the timing.
-
-
I got it figured out,
I rebent the pri. to sec. rod a little tighter and that fixed the problem, I guess that the motor had great vacuum that it caused the sec. to pull open at an idle. Making the rod shorter worked.
I just would like to thanks to everyone for all their input on this, I think thats what makes this site so special for the fact that all of you are willing to add your thoughts on a problem..... Thanks Again!!!:idea:
Dan
-
I've run into this 'high idle until shut down and restart' when using the weaker tension (faster to open) vac sec springs. Off hand, I don't see any issue with making the rod a little shorter (as long as it doesn't bind) as you have done.
-
Oh, BTW, engine vacuum does not effect the vacuum secondaries. It works off of airflow. There is a channel in the primary bores, that when airflow going thru primaries gets to certain level, will cause a vaccum in this channel, which is connected to vac secondary mechanism. There is typically a channel like this in the secondary side too, so as airflow gets to a certain point here, it adds to the the vac signal from primaries and pulls secondaries open even further.
So, yes, it is vacuum operated but not from engine intake manifold vacuum.
Just wanted to point this out to everyone for it is a very common misconception and is good info for knowing more about how carbs work.
-
CFM, Your right about that. After having this problem I did research the vac. sec. circuit. I should have said air flow. She runs great!!!:)
