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| Vapor Lock https://www.smwebhead.com/phpBB3/viewtopic.php?f=3&t=8485 |
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| Author: | ievery0912 [ Thu Oct 13, 2011 1:55 pm ] |
| Post subject: | Vapor Lock |
I have a 1998 Four Winns 4.3GL and I have been having issues with what everyone is calling vapor lock. I thought it was a fuel pump issue and replaced it, but the problem still continues. My four winns dealer in the area went out of buisness, so I tried another boat mechanic and he also stated vapor lock and sugessted a $300+ fix (inline electric fuel pump). The local auto mechanic suggested replacing the fuel cap. Not sure what to do. Anyone else having this issue ? |
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| Author: | Paul I. [ Thu Oct 13, 2011 10:50 pm ] |
| Post subject: | Re: Vapor Lock |
I thought vapor only happens when the fuel gets over 90 degress, yes?? Wrong time of year for this to happen. |
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| Author: | aguyindallas [ Thu Oct 13, 2011 11:41 pm ] |
| Post subject: | Re: Vapor Lock |
Is this something that a bad anti siphon valve could cause to happen? |
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| Author: | 298VISTA2000 [ Fri Oct 14, 2011 5:59 am ] |
| Post subject: | Re: Vapor Lock |
Aguyindallas might be on to something. You might want to see if your check valve (a/k/a anti-siphon valve) to the gas tank is too tight because that will keep fuel from properly flowing. I had fuel delivery issues with my generator and my tech changed the plug(s), fuel pump, fuel line and finally discovered that the check valve to one of my gas tanks was way too tight for the gen's fuel pump to deliver a proper fuel supply. |
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| Author: | LouC [ Fri Oct 14, 2011 11:41 am ] |
| Post subject: | Re: Vapor Lock |
Vapor lock can happen when the engine, intake manifold or fuel lines get hot enough that the liquid fuel boils inside, which will keep the engine from running, since it needs liquid fuel in carb bowl for the carb to work right. But as noted, it happens with very high temperatures, or can happen at high altitude, because of the lower vapor pressure at altitude. I have never had anything like vapor lock in my old 88 4.3 with the Rochester Quadrajet. I'd check the whole fuel delivery system to make sure everything is right before changing to an electric pump. Fuel tank vent, anti siphon valve, fuel pump itself, filter, and the small inlet filter at the carb (if any, most Rochesters do have them). I had a bit of a vapor lock problem years ago on my old 70 Ford Torino with a 302, in very hot weather with the AC on the engine would be hard to re-start. I solved it by putting heat insulation on the metal fuel line from the pump to the carb to keep the heat from the engine from heating up the fuel line. The other thing that sometimes works is to use an insulator under the carb flange gasket, this raises up the carb slightly and keeps it a bit cooler than otherwise, not sure if these are still available but they were used back in the day when we had all carbed engines. |
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| Author: | 97_245_sd [ Fri Oct 14, 2011 1:45 pm ] |
| Post subject: | Re: Vapor Lock |
A potential way to check for vapor lock is to keep the blower on the entire time while running the boat, and/or opening the hatch or cushions covering the engine. That should let enough cool air in to prevent vapor lock to see if it is the root cause. If so then the previously mentioned insulation on the fuel line might help. To test for the gas cap theory you could leave the gas cap slightly loose so that there won't be a vacuum created in the fuel tank. Just be careful to avoid spilling any fuel in the water so you don't get into environmental trouble. |
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| Author: | BoatCrazy [ Sat Oct 15, 2011 7:27 pm ] |
| Post subject: | Re: Vapor Lock |
I have a 2001 H180 with a volvo 4.3L GL. I had a similar problem last summer. We had been tubing and skiing and then went to sit in a cove for awhile. When we went to leave the cove, I made it just outside the no wake zone and she died and I couldn't get her re-fired. After getting towed back, I checked the fuel pump and anti-siphon valve, but both seemed fine. The only thing I noticed was that the engine compartment was pretty hot and I rememered that my brother had layed his towel on the sunpad and had slightly covered the vents to the engine compartment. Since then I've made it a point to run the blower until the air coming out is cool and I've had no problems (even on 95 degree days this summer). |
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| Author: | Borchik [ Sun Oct 16, 2011 3:47 pm ] |
| Post subject: | Re: Vapor Lock |
putting an inline electric pump is not a fix, its a cob. check your venting as well as the antisiphon valve. Chances are its not vapor lock. |
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| Author: | hellasnow [ Tue Oct 18, 2011 5:58 pm ] |
| Post subject: | Re: Vapor Lock |
I've had similar problems with my 2000 190 5.0GL. i put in the fuel line insulator which seemed to have helped for the Denver area heat and altitude. hadn't happened to me all year but then again a hand full of times while at lake Powell last month. granted i had a pretty full load and both compartments beside the motor were completely full of gear plus air temp of close to 100. I've found if i just let her sit for a few minutes run the blower, relax in the sun, take in the view, grab another cold one then try starting by pumping the throttle and or holding her WOT she'll usually come around without to much hassle. guess I've just learned how to work around it since it only happens in extreme heat and gear loaded up on my instances. I'd try the fuel line insulation first, not to expensive and fixed my problem until it heats up big time. good luck. |
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| Author: | ievery0912 [ Tue Oct 18, 2011 7:58 pm ] |
| Post subject: | Re: Vapor Lock |
The Vapor Lock that I had was last summer when we had the hottest summer. I am adding another blower to see if this helps |
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