Need a little help....

['78 gt boat]

I've got a Holly marine 780 cfm carb and I'm having a problem with the vaccum secondaries sticking after I have run it WOT. When I bring it to an idle I have to open the engine cover and manually drop the RPM's. What's the best way to fix this?

[RICHARD TILL]

is the spring still on top of the vacuum diaphram? is the diaphram old or hardened? disconnect the rod from the diaphram and check butterflys and shaft for free travel. if not, you might have a warped throttle shaft or plate.

[Speed955]

Hope this doesn't come off wrong, but is the carb totally clean, no gummed up parts etc.? May try cleaning it really good and put some Marvel's on all the moving parts like the shaft and linkage.

['78 gt boat]

It is a rebuild from Stahle Performance and just put on last year. I will try to get some pics of it tomorrow due to the fact that I'm a total novice to carbs.

[GofastRacer]

On the opposite side of the diaphram there's an arm from the primary to the secondaries and a curved slot, that arm returns the secondaries to idle position, make sure the arm is adjusted right(by bending it)!..
http://www.***boat.com/forums/attach...1&d=1176470968

[cfm]

It is a rebuild from Stahle Performance and just put on last year. I will try to get some pics of it tomorrow due to the fact that I'm a total novice to carbs.
Send it back and tell'm to fix it.

[gn7]

On the opposite side of the diaphram there's an arm from the primary to the secondaries and a curved slot, that arm returns the secondaries to idle position, make sure the arm is adjusted right(by bending it)!..
http://www.***boat.com/forums/attach...1&d=1176470968
DITTO, the rods job is to shut down the secondary blades,if it's not set right they won't shut all the way and you need to tweek it a little(straighter)

[RICHARD TILL]

thats right about the rod. i shoulda thought about that.

[GofastRacer]

thats right about the rod. i shoulda thought about that.
is the spring still on top of the vacuum diaphram? is the diaphram old or hardened? disconnect the rod from the diaphram and check butterflys and shaft for free travel. if not, you might have a warped throttle shaft or plate.
Still stuff to take into consideration though!..

['78 gt boat]

Thanks for all of the info. I still need to get to my boat to get a picture. Maybe I'll just send it back to have it fixed like suggested. Thanks again