oilleaker1
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Post by oilleaker1 on Jul 27, 2017 13:37:18 GMT -5
Very interesting observation. My 2A has a glass bowl. Hummmmm!
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Post by cline48 on Jul 27, 2017 13:51:54 GMT -5
The bowls on my fuel pump and Carter Fuel Filter are both glass. After a long hot pull I try to do an idle cool before I shut it down. I have had hard starts up in high elevation but not so much down here at 1200ft. It always starts. Knock on wood.
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oilleaker1
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Has Jeep Disease
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Post by oilleaker1 on Jul 27, 2017 17:07:48 GMT -5
Up that high, few Jeeps do not have hot start problems. Now if they ran on propane---------probably not.
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rudycon
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Post by rudycon on Aug 17, 2017 11:45:28 GMT -5
HOT STOP
Depending on how long you sit, I think that sometimes a hot stop/hard to restart is actually flooded. The carb, no longer flowing air and vaporising fuel to cool it down, and the engine fan no longer moving air, heats up. The fuel in the bowl boils, and goes...wherever. I have a video on youtube of my carb splurting boiling fuel, leaking recondensed liquid fuel out the throttle shaft, and whistling like a teapot! Looks...Dangerous! Rich mixture for sure when you go to restart. Let it sit long enough and that fuel vapor condenses and pools in the intake manifold. When you go to re-start, that fuel also makes for a real rich mix or flooding. Let it sit long enough and all that fuel evaporates to atmopshere and the rig restarts normally. Another sign that the hot stop = hard to start = actually flooded is that it doesn't take long to learn that the best way to get 'er restarted is to hold the throttle wide open and crank 'till it starts. I don't think you are just refilling the bowl because my electric pump is quick to refill the bowl before I even hit the starter and it still might be hard to start after a 5-10 minute trailside photostop. One of my hot stop tricks is to switch off the electric fuel pump before I shut off the engine. Less fuel in the bowl makes for less boiling fuel. Maybe Not a good idea to drive on rough stuff with no fuel in the bowl. I dented a float once. Another trick is the simple metal heat shield now running under my carb. It seems to keep a lot of exhaust manifold heat from the carb.
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Deleted
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Post by Deleted on Aug 22, 2017 10:58:43 GMT -5
After just returning from the mountains, I will add more observations. Engine temp is critical to vapor lock, my cousins 3B was in the 200+ range on Imogene pass, I watched the fuel boil in the pump (Glass bowl), he poared water on it a couple times but eventually was towed to the Summit. Others had issues as well, my trusty 2A even stumbled a few times. I believe my cousin had a 180 deg. Stat. A really cool period correct chaff guard, and a fairly good load with family and a winch, after removing the chaff guard the problem went away for him the rest of the trip, keep in mind the ambient temp was in the upper 50's at altitudes over 9000 ft, but pulling very steep grades on switchbacks on a 1/2 tank of gas makes heat. My 2A in the same situation never exceeded 180 deg.
That being said,
1) Save the cool accessories for the Jeep show on level ground!
2) Make every effort to keep the underwood & engine temps below 180 deg., 160 deg. Stat is critical!
3) Top off your fuel before running steep grades at altitude, the easier the fuel pump has to work, the better off it is.
Lee.
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oilleaker1
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Post by oilleaker1 on Aug 22, 2017 13:06:16 GMT -5
I'll add to Lee's observations: my GPW has to draw fuel out of the top, down the back of the tank and over to the passenger side. Then up the firewall to just under the hood where it goes through a stock cartridge WW2 fuel filter. It's even F'd! Then down and around the front of the engine into the fuel pump. From there it goes up , through another filter and into the carb. Runs fine until you get over 10, 500 feet and are going up a steep hill running 190 degrees temp., and the tank is about half full. It never vaporlocked. It just wouldn't pull the fuel through all that crap. I'd get it running by hand priming it with the lever at the fuel pump. Topping the tank off helped too. Oilly
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Post by brucew on Aug 23, 2017 12:25:50 GMT -5
The MB's and GPW's have a lot of extra fuel line and the filter exposed to underhood heat, most of it right where all the hot air collects trying to find a way out. Even at less exteme altitudes, like the BHR, NCR, and FCT, they seem to have more than their share of fuel delivery problems. A lot of this is thought to be vaporlock, but as Oilly says, I don't think that's it. I think a lot of it is caused by air leakage at that firewall-mounted filter, either at the fittings or the bowl gasket. If everything is tight, once fuel makes its way "over the hump", it should siphon from then on with no trouble. Like an irrigation tube (I hope some of you know that term-) works. If you poke a hole at the top of the hump in the tube, it will not siphon, water flow will stop. Speaking of accessories, the glass-bowl fuel filter mounted at the carb inlet is a cool (well maybe not so much) accessory and does an important job, but it hangs right out there in the hot air blast from the fan, and looks like a heat-catcher to me. B-dubya
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Post by Scoutpilot on Aug 23, 2017 13:57:02 GMT -5
As long as the fuel line is routed away from the exhaust, a carb-mounted filter is in no danger of overheating, under normal circumstances. I’ve been running a filter at that location for almost two decades with no loss of service due to heat. I could expound on the myriad reasons for heat to be a problem but I often find that a “vapor lock” is the cumulative end of a list of small problems often coupled with the aforementioned altitude-related issues. The large military strainer on the pax firewall was placed there specifically to keep it away from heat related issues. Again, many small issues, taken in toto are the culprits.
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Post by brucew on Aug 23, 2017 21:38:50 GMT -5
As long as the fuel line is routed away from the exhaust, a carb-mounted filter is in no danger of overheating, under normal circumstances. I’ve been running a filter at that location for almost two decades with no loss of service due to heat. I could expound on the myriad reasons for heat to be a problem but I often find that a “vapor lock” is the cumulative end of a list of small problems often coupled with the aforementioned altitude-related issues. The large military strainer on the pax firewall was placed there specifically to keep it away from heat related issues. Again, many small issues, taken in toto are the culprits. I mostly agree with you Scout, but there is nothing "normal circumstances" about a long, hard pull at 12,000+ ft. And, anything that increases surface area available to hot fan wash is a potential contributor. Not to minimize your knowledge or experience, but your two decades of service are at what, 11,500 ft or so, less than the environment we're talking about? And at what kind of grade? 2%,3%? The grades we experienced were easily over 10%, maybe 15% or more. Definitely not "normal circumstances". BW
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rudycon
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Post by rudycon on Aug 25, 2017 9:34:06 GMT -5
Lee's "engine temp is key" line is important. I noticed the "modern" plug wires on my boiling carb video. That was back with the 2 row radiator and 180 degree thermostat. That setup used to overheat (It would boil over when the gage hit 212 despite antifreeze and a 4 psi cap at 9,000 feet.) pulling grades longer than 4 miles. The carb doesn't boil like that anymore.
With the studebaker carb on the "wrong" side of the engine, I also have a extra fuel line under the hood. As little as possible, but it is there on the firewall. I do what I can to keep the underhood temps low. 160 degree thermostat (gets up to about 185 on the longest pulls) I raised up the back of the hood hinge as high as it would go to let some of the hot air out the back. Header wrap on my down tube. Sure it'll rust out sooner, but it was already rusty anyway and the wrap was leftover from something else.
Frankly, I think the 160 degree thermostat helps the most.
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Deleted
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Post by Deleted on Aug 25, 2017 17:35:32 GMT -5
Frankly, I think the 160 degree thermostat helps the most. I could not agree more!, if I used my Jeep in the winter months, I would install a 180 deg. For the sub freezing temps, and to ensure the motor oil gets up to temp to burn off acids and condensation. Otherwise a 160 is the answer. Lee
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Post by brucew on Aug 26, 2017 13:19:25 GMT -5
Frankly, I think the 160 degree thermostat helps the most. I could not agree more!, if I used my Jeep in the winter months, I would install a 180 deg. For the sub freezing temps, and to ensure the motor oil gets up to temp to burn off acids and condensation. Otherwise a 160 is the answer. Lee I agree too, except - the F-head, which has no intake manifold as such, and no way to heat the carb and inlet charge except with hot coolant, must have a 180* thermostat in order to run well on even a cool September day. BW
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Post by cline48 on Aug 26, 2017 15:40:37 GMT -5
The only time I had a problem was after a long pull and did not do a cool down idle. If I let it idle it seemed to start Ok. The Farmall switch makes it easy to shut down right Lee. I did have a problem with an empty tank of fuel going up Imogene pass. Had a hard time starting. She loaded up and Sir Lee had a can of ether it started. No problem the rest of the way to the summit. I do have a glass bowl fuel pump and a Carter fuel filter. It seems not to have a problem with vapor lock. My header pipe is rapped in Heat Cloth also. I do have a Carb heat shield I may install to see if that helps with the hot restart.
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Deleted
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Post by Deleted on Aug 26, 2017 16:18:39 GMT -5
I could not agree more!, if I used my Jeep in the winter months, I would install a 180 deg. For the sub freezing temps, and to ensure the motor oil gets up to temp to burn off acids and condensation. Otherwise a 160 is the answer. Lee I agree too, except - the F-head, which has no intake manifold as such, and no way to heat the carb and inlet charge except with hot coolant, must have a 180* thermostat in order to run well on even a cool September day. BW True kinda!... Yes the F head has no manifold per say, and no heat riser, but it does have a manifold built into the cylinder head, and the head is water cooled, so indirectly it heats the incoming fuel mixture. My old high school ride, a 56 cj5 ran a 180 stat. and never had any trouble here in the oak savanah of eastern MN at +-800 ft above sea level, I did have trouble under 10 deg (F) with the carb icing up, more so if it was snowing or very humid, but an L head would do the same. That being said, if I ran a B in the mountains I would run a 160 stat. To lower under hood temps. I understand your point well Bruce, but the F head is also a larger heat generator and 15 horse more a than its older brother, I would not take a chance. Lee
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Post by m38mike on Jul 9, 2018 6:31:28 GMT -5
There are 5 places I can think of where you can drive above 13,000 feet in CO. Dead ends to Mt. Evans and Pike's peak summits. Plus Mosquito, Imogene and Argentine passes. If you want to take your carburetor car up there, use good gas and keep the fuel temps under 90 degrees. Don't forget the regular favorite of Mt. Antero for your 13,000 foot list. We usually spend enough time on the 13,000 foot bench to let engines cool down before we start back down. So we've have very very few cases of vapor lock there.
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