Fuel leaking out of primary Venturi
Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=31429
Printed Date: April-17-2025 at 1:13pm
Topic: Fuel leaking out of primary Venturi
Posted By: Frankenotter
Subject: Fuel leaking out of primary Venturi
Date Posted: September-03-2013 at 6:19pm
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So I got the carb rebuild kit and threw it together. Got it on the lake today and it runs a little better, however........ After running it at half power and full power, there were no drips from the forward Venturi. When power is reduced to idle, the venturis start dripping within 3min on the spot. I adjusted the the forward float level so that it would cut the fuel off sooner. This had no effect. I ran it again and it runs like a Swiss watch until 3min after the power is reduced to idle. Then the venturis start dripping again once the bowl level catches up. How do I stop the dripping? Could fuel pressure be a factor in this equation? Thanks Chris ------------- 1999 Ski Nautique 196 |
Replies:
Posted By: skutsch
Date Posted: September-03-2013 at 8:39pm
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Who is Barb and what is she doing to your Venturi ------------- Our http://www.correctcraftfan.com/diaries/details.asp?ID=4669" rel="nofollow - 98 Sport Nautique My Dad's 63 Ski N |
Posted By: Frankenotter
Date Posted: September-03-2013 at 10:21pm
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Whoops. Just noticed that. Thanks Steve. Anyone have ideas as to the cause of the problem? I resfuse to believe I stumped the forum. C ------------- 1999 Ski Nautique 196 |
Posted By: Dreaming
Date Posted: September-03-2013 at 10:31pm
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sounds like your needle/seat are not sealing. try adjusting the float again, and if you want to check the n/s, use a hose and blow gently into the inlet (hose connected to the fuel inlet) then move the float up and down see if the airflow stops as the float rises. floats sometimes need a little more tweaking based on the angle that the engine rides at... the fuel level will be too high before the n/s shut off the flow. If the flow doesn't stop when you manually lift the float, you got a bad N&s combination. it happens from time to time. |
Posted By: gun-driver
Date Posted: September-03-2013 at 11:45pm
Isn't that what Barb's for???? 
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Dreaming wrote:Posted By: sams 85
Date Posted: September-03-2013 at 11:54pm
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correct me if I'm wrong as i have been tinkering on my carb tonight, but on mine there is no needle/seat to adjust. the bowls are self leveling or at least mine are. yours still might not be sealing properly but thats unlikely if you just did a rebuild. i do know that junk in the gas getting in there will cause them to not seat properly. thats another possibility what fuel pressure are you running it at?? http://www.amazon.com/dp/B000M2AZIS/ref=asc_df_B000M2AZIS2696041?smid=ATVPDKIKX0DER&tag=dealt733063-20&linkCode=asn&creative=395093&creativeASIN=B000M2AZIS" rel="nofollow - good pic of my carb this is what mine looks like... no needle/seat to adjust |
Posted By: Gary S
Date Posted: September-04-2013 at 1:53am
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You can adjust yours,you have to remove the bowl and bend the tang that touches the needle. If this was a Holley kit,the needles and seats have been hit or miss lately ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: skutsch
Date Posted: September-04-2013 at 2:00am
Paul, that right there is some funny stuff! Good edit! ------------- Our http://www.correctcraftfan.com/diaries/details.asp?ID=4669" rel="nofollow - 98 Sport Nautique My Dad's 63 Ski N |
Posted By: Dreaming
Date Posted: September-04-2013 at 2:53am
my wife would wonder what was up if I called her Barb  hopefully those needle and seats aren't bad, and the float only needs a little tweaking |
Posted By: SNobsessed
Date Posted: September-04-2013 at 10:39am
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I'm going to use this needle/ seat at next rebuild: http://daytonaparts.com/daytona-carburetor-float-valve.html" rel="nofollow - Daytona ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: phatsat67
Date Posted: September-04-2013 at 11:23am
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+1 Gary. I got the point on all of my snowmobile carbs I would re use 30+ year old needle and seats because the new ones would always blow fuel out of the vent tubes as soon as I would start them. Nothing is more frustrating than peeling a pretty rebuild carb back apart. I had to replace the rear N/S on a brand new Holley here in the shop in the spring. ------------- |
Posted By: GottaSki
Date Posted: September-04-2013 at 11:57am
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I've seen this. Two possible conditions...If you have a vacuum leak, or if the Primary idle fuel orifices are still clogged, the idle stop get moved far from where it should be just to make it run. Is the base plate warped? are you using a good thich felpro base gasket, not the crap in the rebuild box? If the idle fuel orifices are clogged, its now idleing on the transition slots and running off the mains at idle. This will eventually perculate fuel up to the boosters and you will see that drip. I don't think its the needle/seat. Your idle mix screws are likely only modestly effective right now. You should be able to shut the engine down with one turn closed on either screw when its idleing on the correct idle furel circuit. If not, the metering block needs unclogging. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Frankenotter
Date Posted: September-04-2013 at 12:47pm
Everything you just said here is right on. I used the gasket that came with the rebuild kit. Now how do I tell if its a vacuum leak or the idle fuel clog? the idle mix screws don't have much of a reaction right now and I thought it was because of the dripping condition. Ill replace the gasket as well. Which one should I get? Thanks for all the replies gents! Chris ------------- 1999 Ski Nautique 196 |
Posted By: TRBenj
Date Posted: September-04-2013 at 1:58pm
Not so fast, Chris!
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Posted By: Frankenotter
Date Posted: September-05-2013 at 7:28pm
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Success!!! I pulled the carb back apart with the intention of ordering new gaskets (which I probably still will). In the process, I noticed that the seat in the forward bowl was loose. I tightened it back down, trimmed the base plate gasket to fit better, and reassembled. It fired right up and no dripping. Took it for a test run on the lake today and it was solid. -------HOWEVER--------- I need some help setting the needle screws. I'm not really sure where the nominal position is for them. Right now everything is smooth except when I push the power forward fast. It bogs down, coughs, and then catches back up and goes like normal. Is that too lean? Too rich? Need some advice. Thanks. ------------- 1999 Ski Nautique 196 |
Posted By: skutsch
Date Posted: September-05-2013 at 7:31pm
Very impressive, all that messing around with leaking fuel and taking carb apart and back together and you didn't blow your boat up even once, nice work! ------------- Our http://www.correctcraftfan.com/diaries/details.asp?ID=4669" rel="nofollow - 98 Sport Nautique My Dad's 63 Ski N |
Posted By: Dreaming
Date Posted: September-05-2013 at 10:04pm
nice! Setting the mixture screws is a process that is best explained by someone who understands carbs better than I; however, It could be that your accelerator pump is not quite adjusted correctly. do you get a good steady stream of fuel into the carb throat as soon as you start moving the throttle forward? |
Posted By: phatsat67
Date Posted: September-06-2013 at 10:18am
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Did you use the power valve in the kit? Accelerator pump spraying correctly? Did you make sure you got the accelerator pump arm back under the arm coming from the bell crank properly? Make sure you didn't adjust the bolt to tight and not allow enough fuel to be pulled into the pump when you return the throttle to closed. Two ways to adjust idle mixture screws. The baseline starting point is 1 1/2 turns out from lightly seated. From there you need to listen very carefully to the engine while adjusting either screw to the point that it runs the smoothest. Idle RPM will increase slightly at that point but hardly audible. Most recommend a tach that operates by 10 rpm movements. After that you need to try various key start conditions to confirm that the screws are adjusted properly. Also listen for smooth in gear operation and no stumble going into gear. The other way is to buy a vacuum gauge and adjust each idle mixture screw to the point that reads highest vacuum on the gauge. Then you still go through the operational process of how it runs how it starts etc. All of this happens at operating temperature. ------------- |
Posted By: 81nautique
Date Posted: September-06-2013 at 10:46am
Boat must be in gear under load to do this though. I leave mine on the trailer in forward idle, that loads the motor enough so you can set the idle mixture for either highest rpm or pulling the most vacuum. I prefer vacuum method, adjust to strongest vacuum then adjust idle speed(not mixture ) back to the factory setting. Forget the power valve for now, it's not in play on takeoff so it's not the problem. Did you adjust the accel pump when reassembling the carb? Gap and procedure should have been in your assembly instructions but if not google it. You should have a good strong squirt instantly off idle. Also check that your timing is correct. ------------- You can’t change the wind but you can adjust your sails |
Posted By: phatsat67
Date Posted: September-06-2013 at 11:37am
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Good deal Alan, I forgot about pushing the trailer. ------------- |
Posted By: Frankenotter
Date Posted: September-06-2013 at 4:36pm
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Zach and Allen thanks for the info. That will give me a great place to start when I get home from this trip. To answer some questions: - yes I did install the new power valve from the kit. Both were 2.5's. - yes there is a squirt of fuel initially when applying power. - I did gap the arm that comes off the front bowl diaphragm to the holley tolerance (.15) with a feeler gauge. It runs great in every condition (idle through full power). The only time it bogs down is if I hit the gas really fast. Ill put it in the water on the trailer when I get home. Where is the best place on the engine to get a tach reading? Ill look for a vacuum gauge in the meantime. Any recommendations for one? Chris ------------- 1999 Ski Nautique 196 |
Posted By: Frankenotter
Date Posted: September-06-2013 at 4:39pm
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Oh, one more note. There is some slop in my morse cable. When I retard the power to idle, it stops a little short of where its supposed to end up. If I tap on the cam just a little bit, it resets to the original spot and all is well. ------------- 1999 Ski Nautique 196 |
Posted By: GottaSki
Date Posted: September-06-2013 at 4:51pm
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adjust the cable end to be putting mild pressure against the throttle stop for consistant idle speeds. Now what cam are you talking about? Hopefully note the The secondary butterfly return cam Regarding the dead spot, are your speaking of hitting the gas from dead stop, or from just on plane? ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: phatsat67
Date Posted: September-06-2013 at 4:54pm
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You want the throttle to close with a little bit of positive pressure so that you need to pull back ever so slightly to get the socket fitting over the ball. This completely parks the bell crank against the idle screw. A cheap vacuum gauge should do the trick. Usually the only 10x rpm gauges you can find are on good timing lights. Does the kit tell you what CC the accelerator pump is? I think 30cc is correct but I could be wrong. See what it does if you are already at speed 20-25 mph then you just stuff it down WOT. ------------- |