Carb problems

[Dead Weight]

I'm having problems with the carbs I have on the hondo (Speedin' Hondo) They are vaccume secondaries and they are not opening. It has a tunnel ram, two carbs, on a roller 427 with I believe a .660 cam. ( I have the cam card at Dragboat Dads house). Is there a way I can convert it to mechanical? Should I take the spring out? I don't know much about the vaccume secondaries, so any help is greatly appreciated!

[Moneypitt]

The sec. are controlled by a diaphram, and the diaphram is controled by a spring. These springs are available from holley in various colors/tensions to dial in your set up. You could be experiencing bad diaphrams, too stiff springs, and a lack of sufficient vacuum to operate the carb. Pull the dia. housing off and suck on it, it should operate, hold your tongue against the port, it should stay pulled. if not the dia is bad, if it stays put you need to know the vacuum pull of the engine and get the right springs.....Is this an on the trailer check out? If it is, don't touch the carbs until you put it on the water as the vacuum impulse on the trailer may not last long enough to pull em open....MP

[Dead Weight]

We had it at the Kings river this past weekend and My dad (dragboat dad) and brother (speedin' ian) took it for a couple runs and the secondaries didn't budge. I don't think there is much vaccume, so can I try taking the springs out all together, or will that not work, assuming I've tested the diaphrams and they are OK. I've been told to take that little ball bearing out in the diaphram too, what's your take on that? Thanks for any info you might have!

[Hotcrusader76]

Something you to need to keep in mind is that if you experience even the slightest amount of bind in the secondary shaft, that vacuum signal will do 'nada' for the opening.
Operate the secondary shafts manualy to ensure they rotate absolutely with ease. Often times a good backfire or two will dis-orient the little teflon seals mounted on the secondary shafts causing a bind, not to mention grime build-up will also cause them to stick.
Lastly, as it was stated above, make sure your diaphragms aren't leaking and that the little cork seal between the vacuum canister and mainbody are still there. Often times over the years the little cork seal drys up and slips out under pressure from the vacuum signal. This induces a vacuum leak and no operation of the secondarys.
PS...You can convert the vacuum secondary to a double pumper but the cost involved out-weights even the price of billet HP Holleys, but it is possible. Remember that Holley vacuum secondary carburetors are double pumpers that have not been completely drilled out.
I convert many double pumpers into vacuum secondary carburetors for the street guys weekly, whom want to run 950 Holleys. With a few lead plugs (same as Holley uses) and re-direction of circuits you have a killer flowing vacuum secondary but this is obviously cost effective when the parts are raw.
Ever see a HP950 Vacuum Secondary marine carburetor?:D
~Ty

[Squirtin Thunder]

I want one !!!

[Dead Weight]

Thanks for the input Hotcrusader. I will take the carbs off tomorrow and test for leaks/binding. So, what you're saying is that I can't just make a linkage to connect the two butterfly rods and dissable the dia. to make it open manually? I just want to make sure they open and wasn't sure there would be enough vaccume with my set-up. It's just a cruiser and I'm not going to set any speed records, but at the same time i still want it as fast as possible!!! ;) Thanks again for the help!

[GofastRacer]

Hmmm, sounds like it's time for injectors!..:D

[Hotcrusader76]

Originally posted by GofastRacer
Hmmm, sounds like it's time for injectors!..:D
:D :D :D

[Moneypitt]

Art, And what time wouldn't be for injectors? The only time I would use injection over carburation is daylight or dark, and only if I'm alone or with somebody.........
Dead weight, before you start screwing things up with assist linkage or removal of springs, make sure the passages are clean, get some vacuum readings, and install the right springs for your vacuum impaired set up. And don't put the little screws in the secondary link slot!!..................Moneypitt

[Dead Weight]

I took the Dia. off the carbs wed. and tried sucking in and holding it, but I couldn't even suck any air in, I took them apart and tried it with the ball bearing (steel ball in air passage) removed and they worked perfect, operated and held air. Can I run them without that bearing in the air passage? What is that bearing even for? The butterfly rods moved freely as well. Thanks again. Sean

[Moneypitt]

NO........

[GofastRacer]

If you take that check ball out, the secondaries will slam open and you will have a bog since there is no squirters for the secondaries!..

[GofastRacer]

Originally posted by Moneypitt
Art, And what time wouldn't be for injectors? The only time I would use injection over carburation is daylight or dark, and only if I'm alone or with somebody.........
:D :D :D :D

[Dead Weight]

so what do I do about the check balls then, because I could not get the dia. to move under my own suction and I can't imagine the venturiis creating more than me. It wouldn't budge at all untill I took them out, but I do see what you mean about them flying open. Is there supposed to be a ridge in the pocket to keep the balls from closing the passage all the way, because as it stands right now, the ball closes off the passage completely. If so, can that ridge wear down? Once again I thank you all for taking the time to help me with this problem and an other questions my family have had over the years! It really cool to have people like you that we can go to that have so much experience! Sean

[Dead Weight]

I had the boat out again this past weekend testing and I got the carbs dialed in pretty good. I ended up taking out the check ball and the secondaries finally opened up, but not all the way. I then put a softer spring in it and they worked just fine. I am having a slight problem with it falling on its face, but only if I jab the throttle real fast from a stand still, if I lay into it on the go or just apply it a little slower, it works perfect. Again, I couldn't get the secondaries to open at all untill I took the check balls out, so my question is, if I'm happy with how it is running right now, can I leave it? or will running it without the check balls cause any damage down the line? thanks again! And thanks again to Sanger Boy for all the Dist. help!

[plaster dave]

call this guy Mike @ 818-425-9057hes the best:D

[Dead Weight]

thanks plaster Dave, Mike told me exactly what I need to know. real cool guy and very helpfull. Thanks to everyone else as well. got the boat running pretty good and mike gave me a couple good tips to get it running even better!