SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: muffbro on December 14, 2012, 06:39:09 AM
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I am rebuilding my Holly 3310-1 780 cfm carb. ( well...maybe )
I have never rebuilt a carb, ( well a few Mikuni's when was like 15 and that was nearly 40 years ago :o)
I have a Holly "fast kit" on the way, but it only comes with one power valve.
Do power valves have the size ....6.5 for example or part # on them so I can get the same powervalve when I remove it?
I know I can just tear it apart and look, but I'm still weighing the wisdom of doing the job myself, and if i decide NOT to , I dont want to bring a box O' parts to someone for them to "clean Up" :mad:
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Fast kit is the way to go...
Power valves are marked/labeled
Check the gaskets in the kit with the old ones
Take your time and clean, clean, clean all the parts
Daniel
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Fast kit is the way to go...
Power valves are marked/labeled
Check the gaskets in the kit with the old ones
Take your time and clean, clean, clean all the parts
Daniel
THX FOR THE INFO !
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Depending on your engine combo (cam, intake...) you might need to go with a lower vacuum rated power valve (4.5 or 5.5) if it's going into a boat.
Have you checked to see how much vacuum your engine is producing at idle? If you have a larger than stock cam there is a good chance the 6.5 power valves will cause a rich condition because of the lower vacuum.
The 6.5 power vavles are a generic "standard" for most street vehicles and will probably have to be adjusted for your application.
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I have not checked vacuum yet, and since I do not know the cam specs I was planning to use the same power valves as are in it now since it ran nice before I pulled it. I can only guess if it has a stock or mild cam in it.... If it DOES have that size PV in
It should I drop It down a size or two?
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If you were running this carb previously without any problems, you should be good rebuilding it as it was. If you had any problems with running rich you might try the lower number power valve (lower vacuum) to delay the enrichment fuel coming in too soon.
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Understood .... I appreciate your input and for taking the time to reply
Thx
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I decided I wanted to rebuild the carb myself....it's old, I'M old..... Maybe we will get along.
Sent from da phone
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I think I found out where the leak was.....I'm thinking the gasket is original .
There was a lot off white residue/ chunks in the float bowl .... And small deposits on the float bowl and metering block.....
Perhaps this would account for the erratic performance the last time out..... It was hesitating when I would nail it real hard.... Anyone have a suggestion for a good carb cleaner/soaker??
Sent from da phone
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They sell Berry Mans carb cleaner by the gallon.
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Depending on your engine combo (cam, intake...) you might need to go with a lower vacuum rated power valve (4.5 or 5.5) if it's going into a boat.
Have you checked to see how much vacuum your engine is producing at idle? If you have a larger than stock cam there is a good chance the 6.5 power valves will cause a rich condition because of the lower vacuum.
The 6.5 power vavles are a generic "standard" for most street vehicles and will probably have to be adjusted for your application.
Crewcheif is your Holley bitch, as in almost ANY Holley questions. He's on my speed dial.... :thumbup:
Personally, on the 3310, I've had better luck at squaring the jets on all corners, leaving the powervalve alone and using the lightest (Yellow) spring in the vacuum actuator (Rolls in play quicker and since there is NO power valve on the secondaries, gives them the head start they need to be seamless, which MIGHT have you jetting down to compensate for this if overly rich). Mind you, I mostly did these on 2-4bbl installs......I beleive larger carbs are really needed on single carb installs, but that is strictly my opinion.
But the Holley rebuild kit will get you going in the right direction. A couple things to check while you are doing it is metering block flatness and flatness of the bowls gasket surfaces as well as the carb body itself. A lot of times they get over tightened and warp and cause weird leaks that lead to symptoms that defy logic. A straightedge is fine, I use a surface plate, but I'm spoiled.
As Crewcheif and a couple others said, these are very different than setting up the carbs for "street" use. We truly only have 3 throttle settings....Idle, WFO, and a specific (Completely dependant on the boat, setup, preference, etc, but will ALWAYS be the same RPM number for that boat once you find what it is.....) mid throttle position for cruising. And THAT is why dialing in on the water, reading your plugs, is so important.
Ray
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They sell Berry Mans carb cleaner by the gallon.
I'll look for some thx ka0...
Sent from da phone
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As Crewcheif and a couple others said, these are very different than setting up the carbs for "street" use. We truly only have 3 throttle settings....Idle, WFO, and a specific (Completely dependant on the boat, setup, preference, etc, but will ALWAYS be the same RPM number for that boat once you find what it is.....) mid throttle position for cruising. And THAT is why dialing in on the water, reading your plugs, is so important.
Ray
pretty much. i do idle, 3k cruise, and WOT. not much inbetween haha.
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I'll look for some thx ka0...
Sent from da phone
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi.walmartimages.com%2Fi%2Fp%2F00%2F07%2F58%2F94%2F00%2F0007589400996_500X500.jpg&hash=6cadd58f24ad4fa08368c53d38dd5e59ccec30d1)
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Reb,
Thx for your time. I'm learning and appreciate the info...
Sent from da phone
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Ok. Disassembled ...... The gaskets are all petrified ...... Like a rock. No wonder it was leaking.... though I am surprised there wasn't more leakage.
Going to get the carb cleaner today.... is there a rule of thumb re: length of time I should let the parts soak?
Sent from da phone
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Ready to clean
Sent from da phone
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The only problem with the 1 gallon can of cleaner is you can't fit the main body of the carb in the can, but buying the 2 1/2 gallon size is not realistic for most users.
If it is really nasty I'll let the parts soak overnight, but normally I'll soak them for a couple hours.
I also use a cheep tooth brush (luckily my dentist gives them out for free) to help clean the tight areas without doing damage to the parts.
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One thing I try to remind people if they're not used to rebuilding carbs...
If you're going to remove the shafts, be sure to hit the butterfly screw areas with a small file to smooth them out before you try to slide the shaft out. Any burr could scrape through the bore and cause problems.
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I think I'll leave the butterfly's alone....
Going to drop it in the cleaner when I leave for work in the am..... Then scrub it tomorrow night. Then start the rebuild.... But I may paint it first....
Sent from da phone
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Anyone have any tips on removing the vent tubes?
The ones in this carb aren't budging..... And I don't want to break em
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Got em..... wd40 and a punch that was just a bit smaller than the tube itself inserted into the vent ....then grabbed it with the ol' vice grips and worked em out...
Sent from da phone
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Working in the carb, I'm comparing parts and there is a good sized difference between the height on the primary diaphragm....Is this because the old one is worn out and collapsed?
Also, the old carb had one 6.5 power valve and the other has NO markings on it at all..... WTF??
Sent from da phone
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The new one pictured is for a 50cc accelerator pump assembly and will not work in place of the 30cc pump you have currently.
The 6.5 marking indicates it will start to open at 6.5 inches of vacuum as the vacuum starts to drop. What other markings were you looking for?
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The new one pictured is for a 50cc accelerator pump assembly and will not work in place of the 30cc pump you have currently.
The 6.5 marking indicates it will start to open at 6.5 inches of vacuum as the vacuum starts to drop. What other markings were you looking for?
Ok first: I will track down a 30cc diaphram...thanks .
RE: powervalve: only one of the power valves that was in my carb has any kind of markings... the one labeled 6.5
the other has no marking on it. :banghead:
The 6.5 has square openings...the unmarked one has smaller round openings.
I would use the old one but the rubber is looking deteriorated on it and I don't really want to put it back in without knowing what it is. Suggestions? Is there a baseline powervalve for my application?
( The engine is supposedly rated at 400-425 HP. At least thats what the original owner told me.) I dont know if that helps..
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Ok first: I will track down a 30cc diaphram...thanks .
RE: powervalve: only one of the power valves that was in my carb has any kind of markings... the one labeled 6.5
the other has no marking on it. :banghead:
The 6.5 has square openings...the unmarked one has smaller round openings.
I would use the old one but the rubber is looking deteriorated on it and I don't really want to put it back in without knowing what it is. Suggestions? Is there a baseline powervalve for my application?
( The engine is supposedly rated at 400-425 HP. At least thats what the original owner told me.) I dont know if that helps..
Ahh, got it.
According to my old Holley book the 3310-1 is the only version of the 3310 series to have two power valves. Originally the carb was equipped with a 10.5 primary (#125-105) and 8.5 secondary (#125-85).
Again, without knowing how much vacuum your engine is producing, it makes it difficult to choose what to use.
At this point, for your application I'd start with and 8.5 primary and 6.5 secondary and adjust as needed after testing.
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6.5 on the left....
On the right ... The Mystery PV..
I'm learning.
I should have checked to see what the Hg was BEFORE I disassembled the carb....
......the 6.5 has a small shoulder, the mystery valve is flat where it seats.....I guess it wont make a difference since there will be gaskets on em both when assembled.... Maybe I need to look closer at the metering block.......
My amateur status as a carb rebuilder is painfully obvious.... Sheesh
Sent from da phone
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Crew..... I ordered the power valves ...6.5/8.5 Oh and I have another 8 million questions.....
Ha
The directions say: ' adjust float parallel to the bowl floor' ..... Ok. Mine are...are they?...am I over thinking this and just should be happy they are level?
Sent from da phone
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The directions say: ' adjust float parallel to the bowl floor' ..... Ok. Mine are...are they?...am I over thinking this and just should be happy they are level?
OK, yes they are parallel to the bowl floor side to side but you normally won't have a problem with that ;) What they are talking about is from front to back. If you adjust the needle and seat assembly the float will raise and lower in the bowl, what you want is for the bottom of the float (while inverted) to be level from front to back. A good way to check this is to use a drill bit as a feeler gauge (Approx 3/8-7/16 is about right).
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Ok..... Back on the stick with the carb today. Prepped and painted with some oil/gas resistant.... high heat paint.
I have an old rock tumbler that I'd like to try on all the linkage components but I'm SkEErt to take them off......it works smoothly so I'm just going to leave it alone.....
It does look better than it was I believe
It's under cover , but I'd like to try and make it cleaner than it was.
Sent from da phone
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Looks somewhat better methinks....
Now to reassemble.... I bought a new fuel log for it as well
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A good way to determine what size power valve you need is take a vacuum reading at idle and divide that number x 2 (13#-2= 6.5) also a little tip is quick fuel,Holley and bg rebuild kits say that there non stick gaskets for the metering plates and bowls if you spray them with Pam cooking spray you can easily change the jets and power valves to dial it in perfect without messing up the gaskets
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That's a good tip!
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A good way to determine what size power valve you need is take a vacuum reading at idle and divide that number x 2 (13#-2= 6.5) also a little tip is quick fuel,Holley and bg rebuild kits say that there non stick gaskets for the metering plates and bowls if you spray them with Pam cooking spray you can easily change the jets and power valves to dial it in perfect without messing up the gaskets
Sounds good .....I'll give that a shot.....
Thanks!
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Log and pressure gauge from White Performance / Kingsport Tennessee.
It's supposed to be 70 degrees this weekend....maybe I'll be able to rewire the trailer too