Fuel disappearing PMO's |
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Fuel disappearing PMO's |
E. Fry |
Mar 20 2024, 03:17 PM
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#1
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Newbie Group: Members Posts: 21 Joined: 3-April 03 From: Olympia, WA Member No.: 510 |
I have PMO's on a SC based 3.2 ltr. in my 914. After the car sits for a time the float bowls are empty. Were the heck is the fuel going? Any ideas?
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BillC |
Mar 20 2024, 03:57 PM
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#2
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Senior Member Group: Members Posts: 536 Joined: 24-April 15 From: Silver Spring, MD Member No.: 18,667 Region Association: MidAtlantic Region |
I have PMO's on a SC based 3.2 ltr. in my 914. After the car sits for a time the float bowls are empty. Were the heck is the fuel going? Any ideas? Evaporation. Or, gremlins are sneaking in at night and driving your car without your knowledge and without refueling it.... (IMG:style_emoticons/default/idea.gif) (IMG:style_emoticons/default/blink.gif) |
brant |
Mar 20 2024, 04:17 PM
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#3
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914 Wizard Group: Members Posts: 11,623 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
Evaporation
Carbs are open systems Unlike modern induction which is a sealed system And the reason they no longer meet emissions standards There was also nice a Honda advertisement where two vehicles were separately placed in a sealed room to test hydrocarbons The mid 80’s Honda was fuel injected and with the motor running The mid 80’s American car was parked and not with the motor running The Honda running produced less emissions than the carb’d car which was not running |
mate914 |
Mar 20 2024, 06:20 PM
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#4
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Matt Group: Members Posts: 748 Joined: 27-February 09 From: Eagles mere, PA Member No.: 10,102 Region Association: North East States |
I have PMO's on a SC based 3.2 ltr. in my 914. After the car sits for a time the float bowls are empty. Were the heck is the fuel going? Any ideas? Mr E. Fry, your car needs driven more often. You will enjoy it. Just starting and warming up helps.... Matt (IMG:style_emoticons/default/flag.gif) |
mepstein |
Mar 20 2024, 06:24 PM
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#5
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914-6 GT in waiting Group: Members Posts: 19,262 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region |
That’s one of the many reasons the industry switched from carbs to FI. My carbed 914 got ~25 on the highway. My FI car got 38.
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campbellcj |
Mar 20 2024, 06:32 PM
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#6
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I can't Re Member Group: Members Posts: 4,544 Joined: 26-December 02 From: Agoura, CA Member No.: 21 Region Association: Southern California |
I have found my car with old Webers really does not do well sitting for more than a few weeks. I've had to unclog gunky idle jets multiple times and unstick dried-up/sunken floats. Lately I make sure to rip it around the neighborhood at least a little bit every couple weekends and it fires right up and runs great.
That being said, definitely check around closely for any seepage on/around the carbs. I would think it'd be visible. |
windforfun |
Mar 20 2024, 08:42 PM
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#7
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Senior Member Group: Members Posts: 1,780 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
That’s one of the many reasons the industry switched from carbs to FI. My carbed 914 got ~25 on the highway. My FI car got 38. (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) Ditto on the improved mileage. My old Jensen Healey had a Lotus engine with carbs. Low mileage & a PITA to maintain. |
stownsen914 |
Mar 22 2024, 08:02 AM
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#8
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Senior Member Group: Members Posts: 913 Joined: 3-October 06 From: Ossining, NY Member No.: 6,985 Region Association: None |
On the carbed 911 racecar, I have a fuel pump switch. Before shutting the car down after a track weekend, I turn off the fuel pump and let the car run the fuel out of the float bowls. Less fuel to evaporate = less crap left behind in the float bowls to clog up the works.
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brant |
Mar 22 2024, 09:42 AM
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#9
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914 Wizard Group: Members Posts: 11,623 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
I drain the bowls after every track weekend now also
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JmuRiz |
Mar 22 2024, 12:25 PM
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#10
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914 Guru Group: Members Posts: 5,425 Joined: 30-December 02 From: NoVA Member No.: 50 Region Association: MidAtlantic Region |
On the carbed 911 racecar, I have a fuel pump switch. Before shutting the car down after a track weekend, I turn off the fuel pump and let the car run the fuel out of the float bowls. Less fuel to evaporate = less crap left behind in the float bowls to clog up the works. (IMG:style_emoticons/default/agree.gif) I plan on doing this as well. |
PanelBilly |
Mar 23 2024, 09:38 AM
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#11
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914 Guru Group: Members Posts: 5,805 Joined: 23-July 06 From: Kent, Wa Member No.: 6,488 Region Association: Pacific Northwest |
I have the same issue with my PMOs on the 3.0. I let the fuel pump run for a bit and then pump the gas a dozen or more times to get enough fuel in the bowls. FI would have been the smarter choice, but the carbs are cool.
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