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Possible vapor lock

Started by tymewyse, July 31, 2023, 08:31:14 PM

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tymewyse

July 31, 2023, 08:31:14 PM
So I have been having an issue with my 1986 FJ1200 stopping running after about 5~10 miles. It seems like just running out of gas. I was given the suggestion from Randy (thank you very much) @ RPM to do a "flappectomy" on the vent in the gas cap. I found the step by step instruction to remove the disassemble the gas cap and went very well except there were a couple of pieces missing  :dash2:. First was the ball and spring that provides detent to the keyhole cover and more importantly was the actual breather assembly. Gasket is intacked and everything else. The question is, can that create a vapor lock since there was nothing to hold the gasket up? My next step will be to pull the petcock and possibly replace it. I will be ordering a new gas cap from RPM and possibly a new petcock.

Pat Conlon

#1
August 01, 2023, 09:24:20 AM
Is your fuel line routed correctly?
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

FJmonkey

#2
August 01, 2023, 10:16:34 AM
If the white plastic (hourglass shape) and brown/orange rubber flap are gone, then the line routing and petcock are the next suspects. Make sure you don't have an in-line filter.
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

tymewyse

#3
August 01, 2023, 08:36:08 PM
Quote from: Pat Conlon on August 01, 2023, 09:24:20 AM
Is your fuel line routed correctly?

Yes I do as per the diagram on the air box

tymewyse

#4
August 01, 2023, 08:37:49 PM
Quote from: FJmonkey on August 01, 2023, 10:16:34 AM
If the white plastic (hourglass shape) and brown/orange rubber flap are gone, then the line routing and petcock are the next suspects. Make sure you don't have an in-line filter.

I will be checking that next. I was thinking of replacing it with the 84-85 petcock from RPM instead of rebuilding the present one.

tymewyse

#5
August 03, 2023, 10:46:02 PM
OK, don't laugh but I am making sure I have the right things in the right places. Believe me I have laughed at my self enough on this project.
The ports in green are the fuel input (aluminum T), the red ports are vent (plastic T) and the blue , just 1 pictured is a vent. I have found several things misplaced or just missing.

Pat Conlon

#6
August 04, 2023, 08:19:50 AM
Nope the green T's are the bowl vents, the reds are the fuel inlets....there are 4 blue nipples (one one each carb) those are your choke vents.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

tymewyse

#7
August 04, 2023, 09:00:37 AM
Quote from: Pat Conlon on August 04, 2023, 08:19:50 AM
Nope the green T's are the bowl vents, the reds are the fuel inlets....there are 4 blue nipples (one one each carb) those are your choke vents.

:Facepalm: Well that would answer it why it's starving for fuel and seeming like a vapor lock. Thank you very much, I will it it tonight.  :wacko3:

RPM - Robert

#8
August 04, 2023, 10:21:11 AM
Quote from: Pat Conlon on August 04, 2023, 08:19:50 AM
Nope the green T's are the bowl vents, the reds are the fuel inlets....there are 4 blue nipples (one one each carb) those are your choke vents.

This is not correct.

The green Aluminum tees are indeed the fuel inlets.

The white (now discolored) plastic tees circled in red are the overflows.

The blue are the vents. There is one of these per carb body.

tymewyse

#9
August 04, 2023, 10:24:47 AM
Quote from: RPM - Robert on August 04, 2023, 10:21:11 AM
Quote from: Pat Conlon on August 04, 2023, 08:19:50 AM
Nope the green T's are the bowl vents, the reds are the fuel inlets....there are 4 blue nipples (one one each carb) those are your choke vents.

This is not correct.

The green Aluminum tees are indeed the fuel inlets.

The white (now discolored) plastic tees circled in red are the overflows.

The blue are the vents. There is one of these per carb body.

Thanks for the update. It looks like I WILL be ordering a new petcock from you soon (next payday)

Pat Conlon

#10
August 04, 2023, 02:58:00 PM
Oops, sorry guys...
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

tymewyse

#11
August 04, 2023, 07:04:56 PM
Quote from: Pat Conlon on August 04, 2023, 02:58:00 PM
Oops, sorry guys...

No problem at all, I appreciate any suggestions.
I just re-installed the carbs and started it up (had to jump it since the battery is slowly going) and it runs but seems to be running on 3 cylinders. When throttling it it is sluggish and backfires. I have the idle mixture screws 3 turns out. There is fuel getting to it since the bowls are full. I just pulled them off again to see if I missed anything during the rebuild.
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