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jblocal
Senior Member Joined: September-06-2010 Location: Stuart, Florida Status: Offline Points: 203 |
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Posted: March-12-2014 at 1:12am |
When my engine is warm idle is nice smooth around 650. If I shut boat off for 15 min when I start it back up it idles rough and I have to bump throttle forward a minute to get it running smooth again. Is this normal? I was thinking it was coil related but unsure.
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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That sounds like it's it within the range of normal to me.
15 minutes is in that weird in-between region of down time where it might benefit from choke, but then again might not. Now, when you're off for the 15 minutes, do you have your ignition on? If so, this would keep the electric choke energized and keep it from closing. How's your choke working in general? Is the is the only symptom you're seeing? |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Now that I think of it. Could also be excess fuel leaking out of the boosters after shut down. When it starts again, you have to run it fast to clear out the excess fuel. This type of leakage is mostly only a problem for mid-length shutdown startups. If you started right back up, or waited a few hours to start back up, it would probably be fine.
The cure would involve checking float levels or a carb rebuild. |
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jblocal
Senior Member Joined: September-06-2010 Location: Stuart, Florida Status: Offline Points: 203 |
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No I don't ever leave ignition on. Carb is a newer Holley about 1 1/2 years old. Recently I replaced exhaust manifolds though and mixed up 2 plug wires I had a backfire through carb when I tried to run it. I had this problem before this though.
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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1 1/2 years old is pretty new, but it's still possible you're getting a little post shutdown drippage.
Easiest way to check is to remove the flame arrestor and look right down the barrels after shutdown. Replacing the regular flame arrestor bolt with this handy thumbscrew makes it easier to do that quickly: |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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We've seen plenty of brand new Holleys drip right out of the box the past few years. I'd look at that first, it's easy enough to do.
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6157 |
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+1
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jblocal
Senior Member Joined: September-06-2010 Location: Stuart, Florida Status: Offline Points: 203 |
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Ok thanks guys going to check that this weekend
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Old School Skier
Newbie Joined: February-22-2014 Location: Cerritos Status: Offline Points: 7 |
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You mentioned backfires through the carb. So you will want to ensure you didn't blow your power valve. To test it --at idle, turn the mix screw (side of meter block) all the way in. If engine dies, power valve is not blown.
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Mine is doing this with increasing frequency. What is the best resolution? I see Holley has a 10-pack kit - keep replacing until you find a good one? I also see on their website that they offer Viton seats & steel seats. Which one is a better bet? Thanks in advance for your advice Tim! |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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Putting an old needle/seat back in has cured the issue for me in the past... Sometimes keeping old junk around comes in handy! I can't comment on the new seal styles, but would like to hear more about them.
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jblocal
Senior Member Joined: September-06-2010 Location: Stuart, Florida Status: Offline Points: 203 |
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Checked the carb this weekend and everything looked good. No dripping after shutdown and power valve is good.
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6157 |
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I have put old ones back in before too. I got to the point on Sled carbs if they didn't overflow while running I just used the original needle and seats because the quality of the new ones was so bad.
Tim, what's that carb parts site that had that new needle and seat design that wasn't quite out yet? Carolina or something? |
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Zach - It is Daytona & they don't have one that fits Holley. I bet it is a patent issue.
I was wondering if the temperature buildup under the dog house has any effect on this problem- It never starts hard when we 1st put in. I might take data of occurrences with doghouse down vs. open before I take apart the carb. |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6157 |
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Interesting to see. I mean you wouldn't think it would because think about how hot a carb gets under the hood of a car with headers in the summer. It may just be because it sat cold all night and all the excess fuel has evaporated from the intake/carb.
Weren't they working on some type of new design or did that get the axe? We will be experimenting with the Quick Fuel M-600 on a big block in a month or so when it warms up a little more. EDIT: When I mess with needle and seat or jetting I don't even take the carb of. A paint cap and removing one of the lower bowl screws works like a charm (or a cut down soda can). The rear bowl will drain completely but the front bowl requires some paper towel at the base of the carb to make for the cleanest drain job. |
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Edit - I emailed them to ask when they might have a Holley version available . . . must be spring fever taking hold here, getting itchy to improve the boat.
Here is Daytona's description (the artwork wouldn't copy); they don't have a size that fits Holley: PLUNGER OR NEEDLE... The plunger in the DAYTONA FLOAT VALVE is aluminum and therefore non-magnetic. A flat alcohol resistant rubber disc fits in a concave opening at the end of the needle. This opening has a high point of center, which allows the disc to float and seat properly at all times. FLUOROCARBON ELASTOMER RUBBER DISC... The flat rubber disc is a synthetic product, and is highly resistant to oxygenated fuel, swelling, and loss of resiliency, when in continual contact with modern alcohol laced gasoline. VALVE BODY... The DAYTONA FLOAT VALVE body differs from the standard valve in one vital respect; one end of the orifice has an inverted flare design and this "raised shoulder" allows the flat fluorocarbon rubber disc to seat perfectly each time, increase fuel flow rate, and control excess fuel pump pressures. The DAYTONA FLOAT VALVE was designed to prevent flooding, caused by dirt, rust, excess fuel pressure, etc. As a result, it does maintain a constant fuel level. In addition, it will increase performance, give smoother idling, and increase fuel economy. |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6157 |
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Nicee.
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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OK, got an email back from Daytona. They do have the their needle & seat available now (it's hard to tell from their web site). They said just to email them the carb# (on the horn) so they can get the right one to you.
This is the direction I will go. Next decision I should make, change floats while I have the bowls off? |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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BuffaloBFN
Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094 |
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Sometimes if they are plastic; not usually. |
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