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Discussion Starter #1
I have a pair of new to me 660s and I need to know what acc pump cams came in them originally. The ones that are in there now are huge and look like the ones Holley shows for Dominators, is that right ?
The problem I'm having is, as soon as I even breath on the throttle they flush fuel like a pair of toilets back there (two big black marks on my garage wall now :mad:). I have them set so they will start to spray as soon as the throttle is moved. Should they work like this or should the start to spray when the sec sides start to move ? They are 1 to 1 linkage but there is slight delay before the sec side starts to open (if that makes sense).
Also I looked at Holleys site and they only show one size squirters for this style carb, its .025 on all 4 corners so I assume that's whats on them.

Thanks in advance for any help.
 

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Don't assume the shooter size is that, bob (GN7) gave me a larger set for mine and a drill bit. It sounded like it was common for guys to open them up.

My 660's have a brown or maroon cam in them, not sure if that's just a faded color or if it's even original. The cam hits the pump immediately on mine, the acc lever is also fully engaged by 2/3 throttle. The linkage has 2 settings for the cam, on mine they are labeled #1 and #2, you could try moving the cam to #2 and seeing what it does.
 

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Don't assume the shooter size is that, bob (GN7) gave me a larger set for mine and a drill bit. It sounded like it was common for guys to open them up.

My 660's have a brown or maroon cam in them, not sure if that's just a faded color or if it's even original. The cam hits the pump immediately on mine, the acc lever is also fully engaged by 2/3 throttle. The linkage has 2 settings for the cam, on mine they are labeled #1 and #2, you could try moving the cam to #2 and seeing what it does.
Same here, 50cc pumps on all four as well... I didn't notice a big difference with moving the cam around, but I'm still playing with them. Welcome to "Gaso O Dumpo" with the 660's :p
 

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660's are notorious for using lots of fuel. Primarily set up for drag racing. If this is a lake boat I would try looking at a set of 450's or 600's. Still plenty of air volume, just more fuel friendly. 50cc acc. pumps are standard on the 4224's. You could try a 30 but I wouldn't advise it.
 

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maybe when people remove the power valves.. they crutch it by using 50cc pumps and drilling the squirters, then pulling jet off the mains and drilling air bleeds to dry it out.
just a thought.
 

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660'sdo not have power valves nor do they have the provision to install them. They have a single 50cc accel pump spraying into all four barrels at the same time from a center mounted four hole shooter. There are possibly 4to 5 un-modified 660's in the world, and I doubt you have a set:D The most common mod was to open the shooters to cover a mid throttle bog. Next most common and some times the biggest screw up is modifing the opening rate on the secondaries to have them open later. This only make them open faster when they do open, and when the pump has dumped most of its fuel already, and therefore bogs even worse. The 660s are the biggest pile of kitty shit Holley ever build, if you use them for anything other than the drags. Idle to full throttle, PERIOD! Do not assume the accel is to rich while the boat is on the trailer. It may, and probaly will stubble the first you stab it at mid throttle. What it does while in neutral, you just have to live with. REPLACE THE BOTH WITH SOME DOUBLE PUMPERS OR LEARN TO DEAL WHITH THEM



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Discussion Starter #7
Thanks for the help guys.
Shaun, did you ever get yours to work right, I remember the thread about yours. You say you have a brown or maroon cam in them, so yours have normal Holley cams ?

What I'm not sure about is if these use normal cams or the ones Holley says are for the Dominators. It makes sense that because of the big pumps they might need the big cams (like mine have), but I wasnt sure if maybe the difference was in the linkage on these.

Mine have cams that look just like the ones Holley lists for Dominators (part #20-81) http://www.holley.com/20-81.asp

They dont look anything like any of ones that are in the kit for normal carbs. http://www.holley.com/20-12.asp But close to the brown one.

Heres a shot of mine (on the left) compaired to an Orange cam from another carb. The color is not right, its a kinda dirty off white color and has the number 336 on it.
 

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I would listen to gn7. You asked for help then shut the door. I know sometimes it is hard to tell the facts from fiction.
I bought the Holley HP carburetor book. It took a lot of study time but well worth the time. The Holley Kits come with several colored pump cams. The cams allow the pump to open and pressurize the nozzles. If the nozzles are too big, you loose your spray too fast. It is a delicate balance between the cam rate and the nozzle size and linkage geometry. Not an easy task. I may take many hours for a novice to find that sweet spot.
I recommend the Holley Book. I think I bought mine from Jeg's. Good luck.
 

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My shooters are stock size, that's what my cam card said from bigs at least. I'm going to assume i have the stock cam too but i cant say for sure because i don't know enough about these carbs. I never got the hickup fully worked out of my carbs but i never played with cams or shooter sizes. I loosened up my acc pump linkage and it helped so i think i just needed to delay my shooters a bit but who knows if that would have caused other problems. I ended up building a bigger motor and bought a set of 750's for it. The 660's are in the garage for now.
 

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I would listen to gn7. You asked for help then shut the door. I know sometimes it is hard to tell the facts from fiction.
I bought the Holley HP carburetor book. It took a lot of study time but well worth the time. The Holley Kits come with several colored pump cams. The cams allow the pump to open and pressurize the nozzles. If the nozzles are too big, you loose your spray too fast. It is a delicate balance between the cam rate and the nozzle size and linkage geometry. Not an easy task. I may take many hours for a novice to find that sweet spot.
I recommend the Holley Book. I think I bought mine from Jeg's. Good luck.
I wasn't trying to shut the door on gn7 (sorry if looked that way). I was just trying to get some info about what was originally in these carbs. So I could tell if someone had done something weird to them or not. I pay attention to everyone's posts and I actually quit messing with them until I get a chance to get it back in the water (next Sunday), because of gn7s post. I will add that nobody has messed with the linkage to the secondary side on mine. And I checked a set that a friend has sitting around (that I didnt know he had) and they had the same cams as mine. So, I might have one of those 4 or 5 sets of unmodified carbs he referred to. ;)

BTW, Thanks Shawn, when I put my cams back in I loosened them up a bit and the cloud of black smoke is way less now. :D
 

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So, I might have one of those 4 or 5 sets of unmodified carbs he referred to. ;)

:D
I don't really know how many unmodified 660's there are out there, but I can assure you I have seen more modified than left alone. And Iam willing to bet that the mods did not accomplish what the owner was looking for. The carb works well for what it was designed for, other than being a little rich on the idle circuit. Holley engineers are no dummys and a hell of alot smart than most "modifiers". They knew what they were building when they build them, it is the owners that bought them for something other than the intended design that screwed up. They are a tunnel ram drag race carb. PERIOD! Good Luck



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