351 w/ Holley Carb 4160 - fuel inlet leakage |
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cnelson0641
Newbie Joined: August-11-2017 Location: Raleigh, NC Status: Offline Points: 28 |
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Posted: September-22-2017 at 1:25am |
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Hey guys
I'm having some fuel leakage where the rigid metal fuel line (connecting the fuel pump to the carb) is leaking carb-side. Before I mention where it's leaking, here's how I (an unexperienced mechanic) see the pieces fitting together (parts below listed in order moving from the carb to the fuel line): - Carb fuel inlet - Bolt A - screws into the carb inlet at what I think is 7/8" or 1" ( can't find a link to this part; anyone know of one? ) - Bolt B - screws into Bolt A at something smaller ( http://www.skidim.com/images/R024025.jpg ) - Gasket - attaches to Bolt B ( between Bolt B and Bolt A; or Bolt B and the fuel line? ) - Fuel line - screws into Bolt B So my issue is that I have slight leakage (1 drop every 20 seconds at 1,200 rpm; I found this while warming the engine up) that appears to be coming from between the carb fuel inlet and Bolt A. I had this issue a couple weeks ago and I was able to tighten Bolt A or Bolt B (can't remember which one actually tightened) and the leak stopped. Bolt B is brass and looks pretty chewed up from where a previous owner probably tightened it as well. I'm wondering: - Has anyone had this issue before? Where was the leakage? - What side does the gasket go on (Bolt A side or fuel line side)? - Should I just replace Bolt B and the gasket? - Can anyone link to somewhere I can buy Bolt A? Thanks! --Chris N. |
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"Two rules, kid - ya gotta want it, and ya gotta give'r."
1983 SN |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Chris,
Leakage between the brass flare adaptor and the carb body is fairly common. It happens when the adaptor and the fuel line flare nut are tightened and the hard steel fuel line is twisted/wound up. Then with engine vibration, the steel line untwists the adaptor. First, get a new gasket for the adaptor. Then after tightening the adaptor to the carb body attach the hard fuel line BUT, put a small amount of grease between the steel fuel line and the flare nut. What this will do is allow the steel fuel line to twist in the flare nut as it is being tightened so the steel fuel line isn't wound up. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11045 |
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Here's a link to what you're probably calling Bolt A. Uunless somebody really mangled it you shouldn't need one unless you just feel like spending money
link You should just need the gasket that Pete gave you a link to. It goes between the Adapter and the fuel bowl. The flare nut threads into the adapter with no gasket or sealer or anything, Do it the way Pete said.in his post There is no gasket because that is a flare fitting and the nut tightens down on the flared end of the tubing to provide the seal with the mating surface inside the adapter. it'll hold a lot more pressure than a carburetor ever sees. Edit I see that I gave you a link to what you're calling Bolt B and I'm calling Bolt A so I don't have a clue what you're calling Bolt A. A picture sure would help right about now |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11045 |
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OK, so I took my own picture
Here's what you should have with a 351 Ford fuel bowl If you have more pieces than that, somebody must have made changes over the years A gasket, the adapter fitting and the fuel line with the flare fitting and it's nut. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21169 |
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Ken and Pete have it covered. I'll add that proper tools are key for getting these joints to be leak free. The adapter is 1" and can be done with a thin adjustable, but a relatively thin 1" open ended wrench is preferred. For the flare fitting, you'll want a true fuel line wrench- 5/8" is most common. (This will prevent further damage from tightening with a typical open end wrench). Amazon sells a set with various sizes for pretty cheap (<$15).
You want to tighten the adapter to the bowl first, then finish torquing the flare fitting into the adapter last. While doing the latter, you'll want to hold the adapter in place with the 1" wrench (putting pressure in the direction that would loosen it in the carb bowl, to prevent it tightening along with the flare fitting). Both pieces need to be pretty tight to keep the joint leak free. |
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11045 |
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Every now and then somebody overtightens things and cracks the fuel bowl in the threaded area causing a leak, so that's something to look at too.
TRB's 2 wrenches suggestion helps to prevent this. |
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spiralhelix
Senior Member Joined: August-06-2014 Location: IL/WI Status: Offline Points: 496 |
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I totally concur with all of the above, especially TRB's wrenches. I too had a leak like yours because I couldn't get it tightened properly. Bought a set of Flare Nut Wrenches (i have one for each connection) and took care of the leak.
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-Spiral
'89 Sport Nautique |
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cnelson0641
Newbie Joined: August-11-2017 Location: Raleigh, NC Status: Offline Points: 28 |
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Ken - you're a life save with those pictures.
I'm going to use this opportunity to outfit myself with proper wrenches, and to get a little more intimate with my baby. I'll inspect the leakage, and in the process check out the rest of that fuel line. I'll update again Sunday evening and take some pictures while I'm at it. --Chris N. |
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"Two rules, kid - ya gotta want it, and ya gotta give'r."
1983 SN |
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4127 |
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Ha Ha. You already did |
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cnelson0641
Newbie Joined: August-11-2017 Location: Raleigh, NC Status: Offline Points: 28 |
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Hey guys
Just got done re-assembling everything and I completely forgot to take pictures . In any case, My setup is exactly like the picture Ken provided. The adapter just needed to be tightened onto the fuel bowl a little more, but the connection between the adapter and the flare nut was so tight that any attempt to tighten the adapter would twist the entire fuel line (which would twist back as soon as I removed the wrench). So I disassembled the adapter and flare nut, put teflon tape on both sets of threads, tightened the adapter to the carb, then the flare nut to the adapter. We'll see how she does next time I take her out. --Chris N. |
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"Two rules, kid - ya gotta want it, and ya gotta give'r."
1983 SN |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21169 |
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You do NOT want teflon tape on the flare fitting to adapter connection. The threads are not the sealing connection there, and adding tape will more likely cause a very large leak by preventing the flare from bottoming out. I would not add tape to the adapter to bowl connection either- the gasket there is sufficient.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11045 |
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I'm just agreeing with Tim here, like me, Pete and Tim said no sealer or teflon tape...........nothing. The flare nut threads into the adapter with no gasket or sealer or anything, There is no gasket because that is a flare fitting and the nut tightens down on the flared end of the tubing to provide the seal with the mating surface inside the adapter. The seal is the nut squeezing the male and female flares tightly together. That sounds a little kinky It might not leak at first, but it will and it won't be pretty. I think this might be the first time that Pete, Tim and I all agreed on something, I'm not sure |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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cnelson0641
Newbie Joined: August-11-2017 Location: Raleigh, NC Status: Offline Points: 28 |
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HAHAHA well at least we have consensus!
Very good point about the flare nut not needing teflon - that should have been obvious. As for the adapter, my initial reaction to "... the gasket should be enough" is "should be, but apparently isn't." Is there any harm in having teflon on the adapter where it connects to the carb? I'd like to employ this until I can get a new flare nut (because its brass and very close to being stripped) and gasket (because it "should be" enough and I bet a new one would help tremendously). How tight should the flare nut be? As tight as I can get it with a normal wrench set or should I break out my torque wrench and do it to spec? --Chris N. |
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"Two rules, kid - ya gotta want it, and ya gotta give'r."
1983 SN |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Chris,
Maybe it's time to ask for help from a friend who may be more mechanically inclined. I started worrying about the fix when you where referring to "bolt A and bolt B" and now with the Teflon tape it pretty much confirms that help would be a good thing. Honestly, a fuel leak is not something you want to back yard hack!! BTW, regarding tightening the flare nut, Tim mentioned way back using a "true fuel line wrench" or more commonly called a flare nut wrench. |
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outerbanked
Senior Member Joined: July-27-2017 Location: seattle Status: Offline Points: 104 |
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Cool Carburetor Tool and Fixed Fuel Line Leak - CorrectCraftFan.com Forums
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=27143 What a fuel leak can look like: https://imgur.com/a/MdGvw Check out youtube and the reference section of this site. I happened to be looking at the Quickfuel install directions last night. I can't remeber exactly, but the wording was setting like "until tight". Reread the prior posts. You can break the fuel bowel if you over tighten. A blue paper towel is helpful at test fire to look for evidence of a leak. You could take the coil wire off and crank the starter (make sure you have water to your cooling or are in the lake). Your line will be pressurized. I think most would just try not too tight and observe. Keep watching it. Thermal expansion can make it fine at idle but leak once warm. There is a prestart check in your manual. Checking the fuel system is a part of it. You will get it. You need to get it for you to be self sufficient out there. |
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cnelson0641
Newbie Joined: August-11-2017 Location: Raleigh, NC Status: Offline Points: 28 |
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Pete - (audible sigh). You're absolutely right, as I learn the basics of this fine engine I need someone a little more mechanically inclined to walk me through some of the finer details. I apologize in advance for the idiotic terms, descriptions, and questions; I understand that there is a TON of basics that I don't know. I appreciate the skepticism and advice to bring in help. That being said, I learn well by establishing my understanding of a system and having others poke holes in it and point out where I'm wrong. With this particular issue, I could not find any manual or descriptions of the fuel line and adapter fittings (SN owner's manual, 351 PCM manual, and the Holley 4160 manual: neither had a description of the fuel bowl, gasket, flare nut, and fuel line), so I resorted to the "Bolt A / Bolt B" description. I now know the proper terms and how the system is assembled.
Todd - You mention Quickfuel install instructions... I couldn't find any Quickfuel parts for the 351, could you link to some? The instructions as well would be nice. I also checked the owner's manual for the pre-start instructions, and all it said was "check the fuel system", but nothing on what to actually check. What I've gathered is: make sure there is no fuel in the sight tube, and no visible leaks. What else should I check? Could someone give me some background on Skidim? I noticed all of the parts recommended for the fuel system do not have a brand; are they produced by Skidim? Can I trust that Skidim has quality products and if they say it fits my engine/boat that it will? As for flare wrenches, I just ordered one from Amazon so I don't muck up the flare nut any more. I'm also going to purchase a gasket and new fuel line since the flare nut on my current one is very mangled and I fear that much more tightening/loosening will strip it completely so I have no grip. Thanks for the healthy skepticism! I'm here to learn and you guys certainly help. --Chris N. |
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"Two rules, kid - ya gotta want it, and ya gotta give'r."
1983 SN |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11045 |
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Chris
Skidim stuff is always good quality. Speaking of good quality you should probably consider getting their flexible fuel line kit, part number 80113 in the link below A little pricey but when you consider that quite a few of those dollars are for the aluminum carb fitting, the fuel line itself isn't a bad price. It's rubber that's USCG approved, It's a whole lot easier to work with and install and it has all the right adapter fittings for both ends. You'll never have to screw around with that metal line again and your newly ordered flare wrenches will still come in handy with this line. link |
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Riley
Grand Poobah Joined: January-19-2004 Location: Portland, ME Status: Offline Points: 7953 |
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Ken, I bought one of those a few years ago and have not had it work out. I have not tried it on a 351 or 302. We originally bought it for a Chrysler with an AFB and it would not fit and I recently tried it on a FE Ford and due to the water jacket on the Wiend intake, it would not fit.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11045 |
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Save it for a 302/351 with the Holley Ford marine style fuel bowl and it's a perfect fit with the stock manifold height. These days the ad from Skidim says it's for a 302/351 link to fuel line and fitting page |
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Jonny Quest
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2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
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shierh
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This doesn't look like a double flair............................................. |
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TRBenj
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Yes it does
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shierh
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umm no it does not.
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21169 |
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On a 3/8” line, it sure does. Better go look at your boat again and calibrate your eyes.
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shierh
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Well I guess id have to see the inside. looks too thin though. Well I not need to calibrate my eyes. I guess ill fly to GA and take a look at Keno's fuel line since this is his photo.
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21169 |
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When did KENO move? I’d try him in NH.
You can also walk into most auto parts stores and look at their 3/8 brake line, which will likely be double flared. http://www.mig-welding.co.uk/forum/threads/making-brake-pipes-flaring-tool-bender.4522/page-4 http://www.allmetalssupply.com/product/hydraulic-tube-flaring-tool-kit/ |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11045 |
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Wow, I come home for lunch and find a good disagreement going on, my name in it and Pete's not involved
Since I took the original picture and I still have the piece of brake line. (there's a bit of a clue right there), I figured I'd take a picture of the end with the label too. Here it is And here's a link with info Click on the picture on the left in the link and you'll find a good cutaway of the double flare on the ends of the tubing. link And one last thing, here's an outline of the state I live in |
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shierh
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Well, that's just too far for me to go and see the standard flare tube and fitting of course if there is beer involved then.................................
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