#1
IP: 174.89.31.125
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Carb Gasket
Finished rebuilding fuel pump and carb.
Benefits noticed include being able to adjust carb so lowest throttle position will allow me to creep forward, instead of always sliding into neutral. Also, when I removed the fuel pump I thought I had good action, as it was, but with the new springs, wow! Stiff priming lever, and it delivers 4.75 psi on gage. Very happy with it all. One question- the gasket supplied to seal upper/lower section has a bit of overhang, and is weeping/soaked in fuel. Just leave it, or best to trim off excessive? I am quite certain I have a good seal between the two pieces, and what I am seeing externally is from a "wicking" effect. Admittedly I may be hyper sensitive to this now, but I would prefer to error on the side of caution. Cheers Jimmy
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Jimmy C&C 29 MK1 Erieau , Lake Erie |
#2
IP: 184.0.17.64
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Jimmy-
In my experience (IME) that dark area is normal. (See pic) The pic is a rebuild after 2 years. If you look closely, you'll see the "darker" area on the excess gasket. I'm not sure why it shows as a darker area. Note that the "inside" area is lighter in color.
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-Jerry 'Lone Ranger' 1978 RANGER 30 Last edited by roadnsky; 07-29-2015 at 10:15 AM. |
#3
IP: 68.111.9.124
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Quote:
The only way to tell for sure is to take the two halves apart and see if there is a seal all around like in Jerry's picture. IMO you are not being hyper sensitive. Don't blow the boat up. TRUE GRIT |
#4
IP: 174.89.31.125
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Gasket was included in rebuild kit from MM. Will return tomorrow to check and snap photo
Worth noting that the MM manual is one of the best written collection of instructions I've ever used. Most valuable tool on board! Cheers Jimmy
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Jimmy C&C 29 MK1 Erieau , Lake Erie |
#5
IP: 207.118.20.35
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4.75 on the gauge seems more than usual or necessary. I doubt you would get that reading when running, only when priming with the pump lever. This may be forcing fuel past the gasket, with or without an overhang. Even so, this is a serious situation. A gasket should not wick fuel. If the seal is indeed good, it will not leak, even at 4.75 psi. If this persists, try seeing if you can tighten any of the bolts around the gasket. If they are all tight,you may have an irregularity in the surfaces of the carb.
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#6
IP: 107.0.6.242
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Quote:
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#7
IP: 32.211.28.40
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That gasket shouldn't wick, even with the overhang.
First thought is that something is hanging up and not letting the two halves come together. Perhaps the venture tube isn't fully seated? I'd try putting it together without the gasket to make sure everything comes metal to metal. I've seen gaskets wick. We had oil wicking with Navy specified gasket material - 1/8" thick neoprene with canvas reinforcement. Oil was following the threads in the canvas. Navy wouldn't believe us - tied up our lab for a month proving what we knew. |
#8
IP: 174.89.31.63
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OK- mea culpa.....
I had to remove the fuel strainer bowel to access the second/rear bolt on the pump. When I put it back together, didn't realize the rubber seal slipped out. Subsequently couldn't get engine to fire up. I primed repetitively, but no fuel flow ( yea- massive air leak will do that). After diagnosing the issue( and retrieving/installing the lost seal from the bowels of the boat), the carb/ fuel system primed quickly Some observations.......... Carb has 4 screws to mate the 2 halves I traditionally over tighten- snapping and striping bolts as I go thru life. Aware of the warnings about soft alloys involved, I didn't this time, however confident I tightened enough. Float was exactly parallel with mating surface, when held upside down. Initial prime pressure = 7psi During running/tuning = 4.75 psi After shutdown, pressure stayed above 4 psi for at least 30 min.Wasnt taking exact notice of reading, but thought that is was great that the system was staying pressurized for so long...... Is it possible at 7 psi (even temporarily)I have "overloaded" the gasket? Thoughts? Fume detector w/ blower relay has been ordered. Hopefully delivered tomorrow Cheers Jimmy
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Jimmy C&C 29 MK1 Erieau , Lake Erie |
#9
IP: 107.0.6.242
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If your needle and seat are holding 4 psi for 30 minutes after shutdown, they are at the head of the class. When the fuel chambers of the carb are full and the needle and set have stopped the inflow of fuel, the gasket should not be exposed to fuel at all. Does your leak/wicking persist after shutdown or does it occur only when the engine is running?
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#10
IP: 32.211.28.40
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To clarify hanley's post, the gasket will be exposed to fuel as the boat rocks and plunges through the waves but the pressure stops at the float valve. The float bowl, gasket, and the carb internals are all basically at atmospheric pressure. With the engine running, there's airflow through the venturi which changes things (and moves the fuel), but that's all low pressure stuff. I saw a document somewhere (Moyer Manual??) that described flows and pressures in the carb at wide open throttle. Kinda went over my head. In my book, it the carb don't work, clean it out (done it a lot lately).
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#11
IP: 107.0.6.242
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Quote:
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#12
IP: 107.0.6.242
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http://www.moyermarine.com/forums/showthread.php?t=242 This is a great reference.
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The Following User Says Thank You to hanleyclifford For This Useful Post: | ||
Administrator (07-28-2015) |
#13
IP: 174.89.31.63
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Hanley/Al - thanks for the link.
As I have only run the the engine Sat/Sun, I can't say with certainty that the problem is persistent. Proof will come with tomorrow's inspection. With the info you have added, I will check for a gap at the front of carb. I'll post a picture of my findings. Extra eyes can't hurt! Cheers Jimmy
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Jimmy C&C 29 MK1 Erieau , Lake Erie |
#14
IP: 71.118.13.238
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Hanley, the carb has an internal vent that feed to the throat chamber under/behind the venturi. I doubt it could get plugged.
I have "sealed" the ends of more than a few 4-screw carbs by running a bead of "hi temp orange or red" silicone around the end of the carb AFTER TESTING!!!! DO NOT USE THE PERMATEX SILICONE WHEN ASSEMBLING!! After the carb has been confirmed good remove and apply the bead on the outside. The one on my carb stays sealed and has for 4 years now others longer. Worry more about sealing the emulsion well in the center first with a distorted "top half". They can be "flat honed" to reseal if you are careful. Done so many times out here for friends. Dave Neptune |
#15
IP: 184.151.36.43
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OK- installed new water/fuel separator, than ran engine.
- before starting, checked gasket and gap. Gasket appeared to dry out, but still double checked front all 4 screws. Got a third of a turn. Attached picture is a 0.002 feeler gauge inserted. I am border line forcing it at this point. Second pic is of fuel pressure gauge, with engine shut of for more than 15 min past. Third pic is where gasket had become some what saturated, after engine ran 15 min. Not sure if you can make out the detail, but when I compress the external flange of gasket with fingernail, a slight sheen appears PO had a little something added, that I cleaned up prior to resembling. It came clean using carb cleaner and a rag. At this point, I am prepared to remove carb, redo with a little sealant, and go again. Can I reuse the soaked gasket? Dry it out? Agree?
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Jimmy C&C 29 MK1 Erieau , Lake Erie Last edited by Jimmy; 07-28-2015 at 08:06 PM. |
#16
IP: 32.211.28.40
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The first picture shows that you have the wrong gasket for your carb. You have a 4 screw carb, and the gasket for a 5 screw carb. And, the carb gasket should need NO sealant. I don't use any, and don't have a weepage problem.
Previous comment still holds - put it together without a gasket and make sure things come together. |
#17
IP: 159.53.174.142
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Quote:
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The Following 2 Users Say Thank You to Bratina For This Useful Post: | ||
Easy Rider (07-31-2015), ndutton (07-29-2015) |
#18
IP: 107.0.6.242
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Look at those beautiful street fittings (from Moyer Marine, I'll warrant).
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#19
IP: 184.151.61.151
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Yup, got the fittings with the rebuild kit. Other than the deflated Canadian dollar, my other issue with ordering from MM is the time it takes to get goods north of the boarder. Neither of these issues are within the control of our Host, and I value this forum, and MM's ability to supply parts, so whenever feasible, I support them. Usually 1 significant shipment a year, of required parts, and a couple miscellaneous parts as I continue to build a reasonable spare part collection.
To this point, I won't get a new carb gaskets in time for Friday nights redo.... After making sure the float is correct, and halves are flush, I can choose to reuse the 3 week old gasket, or attempt to cut a new one from a template. Which would you do, faced with these two options? Cheers, Jimmy
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Jimmy C&C 29 MK1 Erieau , Lake Erie |
#20
IP: 107.0.6.242
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I would attempt to reuse the old gasket. Hopefully you've been careful making sure it does not get torn when separating halves and getting that venturi out. On the 4 screw carb it's real important to get the two pieces plane for a tight fit. If it doesn't look good don't be shy about taking a flat bastard to one piece or the other. Check first with something known to be straight, like a stainless ruler or a square.
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Jimmy (07-31-2015) |
#21
IP: 71.118.13.238
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Trix
Jimmy, if you are successful at getting the gasket out unscathed try this it's worked for me 100's of times on carb gaskets. First carefully wipe it clean and dry, then spray liberally with WD-40 and place in a sealed baggy. Get as much air out of the baggie as you can so the gasket stays wet and set it in the sun or someplace warm for at least an hour. The gasket as it warms will suck u some of the WD-40 and swell up a bit so it can be squished yet again.
DO NOT OVERTIGHTEN THE SCREWS, it just takes a slight pressure if things are flat! Dave Neptune |
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Vermonstah (08-05-2015) |
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