International Full Size Jeep Association
Home Forums Reader's Rigs Tech Library Trail Stories FSJ-List
International Full Size Jeep Association  

Go Back   International Full Size Jeep Association > Tire Kickin' > General FSJ Tech

Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 08-12-2020, 06:11 PM
Ristow Ristow is offline
 
Join Date: Jan 20, 2006
Location: The Great Googley Moogley Midwest.
Posts: 17,240
is the check and weight installed under the screw that holds the booster assembly in place? its the check ball for the accelerator pump.


make sure the heat riser on the passenger exhaust manifold is opening.
__________________
Quote:
Originally Posted by Hankrod
Ristows right.................again,




Quote:
Originally Posted by Fasts79Chief
... like the little 'you know what's' that you are.




Quote:
Originally Posted by Fasts79Chief
I LOVE how Ristow has stolen my comment about him ... "Quoted" it ... and made himself famous for being an ***hole to people. Hahahahahahahahahha!


→ Where the kids hang out...

fsjbuilder.org come for the mindless chat,stay for the hand drawn emoticons.

It's like you're unraveling a big cable-knit sweater that someone keeps knitting...and knitting...and knitting...and knitting...
Reply With Quote
  #22  
Old 08-13-2020, 12:40 AM
Brynjminjones's Avatar
Brynjminjones Brynjminjones is online now
258 I6
 
Join Date: Jun 11, 2017
Location: Derby, England
Posts: 301
Thanks both.
Ristow, I plan to remove the carb again to check so I will make sure. I have spares if anything is missing so will be able to replace.
I'm guessing it'll be fine however, as this was an issue that randomly started one day.

The heat riser is wired permanently open, although I will check again today.

I'm starting to wonder if the gasket on my new power valve could be leaking, although it seems to test good with a vacuum pump.

Michel, the F100 has a 390 V8, so is a very similar setup. I took the top off its carb yesterday after sitting for a week and it wasn't as empty as the Wagoneer's after a single day!
Both in the same weather conditions, except the Ford lives outside.
__________________
1991 Grand Wagoneer - Hunter Green. All stock. Rebuilt 360 with Melling MTA-1 cam.

1998 Cherokee (XJ) 4.0
1997 Grand Cherokee (ZJ) 4.0
1974 Ford F100 390

Last edited by Brynjminjones : 08-13-2020 at 12:49 AM.
Reply With Quote
  #23  
Old 08-13-2020, 02:41 AM
Brynjminjones's Avatar
Brynjminjones Brynjminjones is online now
258 I6
 
Join Date: Jun 11, 2017
Location: Derby, England
Posts: 301
Okay, so I've had the carb off again this morning and I'm still struggling to identify the problem.

The carb gasket/spacer was wet with fuel, as were certain parts of the underside of the carb itself.

From what I could tell, the wettest part was the area circled below, although it looks to me like that is just the vacuum port for the choke pull-off so maybe just a coincidence?

2150 Underside by Brynjaminjones, on Flickr

The power valve cover didn't seem to have any gas in it, although it did smell of gas.
The check and weight for the accelerator pump were both present. I took the pump off too and although it contained gas, it didn't appear to have leaked at all. It has always worked perfectly.

The heat riser has been tweaked so it's always in this position:
I assume/hope this is the open position?

Heat Riser by Brynjaminjones, on Flickr


Finally, I filled the bowl back up with gas and put it over a piece of kitchen towel to see if it leaks. I'll leave it there for a few hours, maybe overnight depending on results.
I've also put a small container of gas next to it to compare how much is lost to evaporation.

Carb Leakdown by Brynjaminjones, on Flickr
__________________
1991 Grand Wagoneer - Hunter Green. All stock. Rebuilt 360 with Melling MTA-1 cam.

1998 Cherokee (XJ) 4.0
1997 Grand Cherokee (ZJ) 4.0
1974 Ford F100 390
Reply With Quote
  #24  
Old 08-14-2020, 04:38 AM
Brynjminjones's Avatar
Brynjminjones Brynjminjones is online now
258 I6
 
Join Date: Jun 11, 2017
Location: Derby, England
Posts: 301
I've just checked on it this morning and a good amount of gas has definitely evaporated, but I really don't think anything has leaked.

The test beaker I put next to it has gone from 2 1/4 to 1 1/2 fl oz over the course of 24 hours, which is exactly 1/3!
I guess that when the engine bay is as hot as it's been recently this would be much quicker.

Gas beaker by Brynjaminjones, on Flickr



It looks like you lot were right! Sorry if it seemed like I doubted the advice, I just really like to verify what's going on!


The only thing confusing me a touch is that there was a tiny bit of gas underneath one area of the carb. It's just the vacuum port that (I think) goes to the choke hot air bleed, so I have no idea how gas could get there.
I've shown the exact port with an arrow in the picture below.

There's also evidence of gas dripping from the port to the altitude compensator, circled in the picture.

Does anybody have any idea why either of these things could be happening?

Altitude Compensator Leak by Brynjaminjones, on Flickr
__________________
1991 Grand Wagoneer - Hunter Green. All stock. Rebuilt 360 with Melling MTA-1 cam.

1998 Cherokee (XJ) 4.0
1997 Grand Cherokee (ZJ) 4.0
1974 Ford F100 390
Reply With Quote
  #25  
Old 08-14-2020, 08:14 AM
wiley-moeracing wiley-moeracing is offline
350 Buick
 
Join Date: Feb 15, 2010
Location: arizona
Posts: 1,263
Again, you will need to put a thick spacer under the carb to help block the heat transfer between the engine and carb, summit racing should have them, 1 to 2 inch spacer of heat resistant plastic will work. The gas is boiling when you shut it down and going into the different areas inside the carb. You may want to install a small electric primer pump inline to help on restart.
Reply With Quote
  #26  
Old 08-14-2020, 09:04 AM
rocklaurence rocklaurence is offline
Moderator
 
Join Date: Jan 14, 2009
Location: 33812, Lakeland, Fl
Posts: 1,772
I had the Long Start and Vaporlock issues with my Jeeps in Florida. That with the Junk replacement Mechanical fuel pumps I decided to replaced the Mec' with electric pumps [Holley Mighty Mit & Red top]. I have had these running for close to 10 years now and both fuel issues were resolved. Some people have issues with Elec' pumps failing but IMO its poor wiring. I run a relay Hot and a ground from the battery to the Pump [- terminated at the pump and frame]. My guess is most pump failures are due to bad grounds.
Reply With Quote
  #27  
Old 08-14-2020, 09:21 AM
babywag's Avatar
babywag babywag is offline
out of order
 
Join Date: Jun 08, 2005
Location: Land of froot loops and cukcoo-nuts, CA
Posts: 9,759
Quote:
Originally Posted by rocklaurence
I have had these running for close to 10 years now and both fuel issues were resolved.

The parts sold today are generally inferior to stuff made 10yrs ago.
It is a roll of the dice for anything aftermarket, especially anything electrical.
__________________
Tony
Reply With Quote
  #28  
Old 08-14-2020, 09:38 AM
Brynjminjones's Avatar
Brynjminjones Brynjminjones is online now
258 I6
 
Join Date: Jun 11, 2017
Location: Derby, England
Posts: 301
Quote:
Originally Posted by wiley-moeracing
Again, you will need to put a thick spacer under the carb to help block the heat transfer between the engine and carb, summit racing should have them, 1 to 2 inch spacer of heat resistant plastic will work. The gas is boiling when you shut it down and going into the different areas inside the carb.

Thanks, a spacer is definitely on the to-do list, but I wanted to confirm that evaporation is definitely the cause before throwing parts at it, especially as it's a new problem. I am starting to think though that it could just be because it's been unusually warm for this country!

Another thing I should clarify is that this gas coming from the vacuum port is after sitting overnight on the bench, not whilst on the car.
The carb was dry when I started, then I manually filled it with gas and left it on a piece of paper towel, so it hasn't been boiled to cause it.


If it does turn out to just be a hot weather/vaporization issue then I'm happy with that to be honest, because it doesn't get hot here very often.

I just want to get my head around how gas could be coming from a vacuum port (although in very small quantities) whilst sitting off the car!
__________________
1991 Grand Wagoneer - Hunter Green. All stock. Rebuilt 360 with Melling MTA-1 cam.

1998 Cherokee (XJ) 4.0
1997 Grand Cherokee (ZJ) 4.0
1974 Ford F100 390
Reply With Quote
  #29  
Old 08-14-2020, 09:56 AM
babywag's Avatar
babywag babywag is offline
out of order
 
Join Date: Jun 08, 2005
Location: Land of froot loops and cukcoo-nuts, CA
Posts: 9,759
Possible cause of mystery fuel area...could be a crack in the housing?
Have seen several 2150s that were damaged by folks overtightening them and cracking the housing.
__________________
Tony
Reply With Quote
  #30  
Old 08-14-2020, 10:26 AM
Brynjminjones's Avatar
Brynjminjones Brynjminjones is online now
258 I6
 
Join Date: Jun 11, 2017
Location: Derby, England
Posts: 301
Hmmm, I wonder. I certainly hope that's not the issue.

It does seem really strange to me as that vacuum port is at the back of the carb, which is surely well away from any fuel passages?


Also, I've just had a look on Summit at carb spacers, and realise that I do already have one!
My intake manifold has exactly this on top, which then has a thick gasket between it and the carb.
https://www.summitracing.com/parts/cwa-j3240515

Is that enough spacer?
__________________
1991 Grand Wagoneer - Hunter Green. All stock. Rebuilt 360 with Melling MTA-1 cam.

1998 Cherokee (XJ) 4.0
1997 Grand Cherokee (ZJ) 4.0
1974 Ford F100 390
Reply With Quote
  #31  
Old 08-14-2020, 02:07 PM
letank's Avatar
letank letank is offline
AMC 4 OH! 1
 
Join Date: Jun 03, 2002
Location: San Francisco
Posts: 3,923
Quote:
Originally Posted by Brynjminjones
Hmmm, I wonder. I certainly hope that's not the issue.

It does seem really strange to me as that vacuum port is at the back of the carb, which is surely well away from any fuel passages?


Also, I've just had a look on Summit at carb spacers, and realise that I do already have one!
My intake manifold has exactly this on top, which then has a thick gasket between it and the carb.
https://www.summitracing.com/parts/cwa-j3240515

Is that enough spacer?


enough, yes.
Do not forget the thin paper gasket between the intake and the plastic spacer. The TSM says mount dry... I use a small bead of Hylomar, last year I did not put enough or missed a spot and it resulted in a intake leak 12 month later...


__________________
Michel
74 wag, 349Kmiles on original ticker/trany, except for the rust. Will it make it to the next get together without a rebuilt? Status: needs a new body.
85 Gwag, 226 Kmiles. $250 FSJ test lab since 02, that refuses to give up but still leaks.

See Ouray 2013, Engine bits and Fuel and brake lines, and Body work

Last edited by letank : 08-14-2020 at 02:19 PM.
Reply With Quote
  #32  
Old 08-14-2020, 02:52 PM
wiley-moeracing wiley-moeracing is offline
350 Buick
 
Join Date: Feb 15, 2010
Location: arizona
Posts: 1,263
Can be a cracked bowl, would need to get some crack detection fluid/spray to see. But honestly you may be better off getting another carb to work with first, would be cheaper than going through all this work.
Reply With Quote
  #33  
Old 08-16-2020, 09:41 AM
Brynjminjones's Avatar
Brynjminjones Brynjminjones is online now
258 I6
 
Join Date: Jun 11, 2017
Location: Derby, England
Posts: 301
Thanks both

The paper gasket is in place and hasn't been disturbed. I'm pretty confident it's not leaking as it runs perfectly and I was able to tune the carb very easily.

I'll inspect closely for a cracked bowl next time I have it off, but to be honest I probably won't play with it much more as it really does run beautifully!

It's only if the bowl keeps draining that I'm concerned, but I expect we'll find it's okay now the weather has cooled down.

Thanks everyone for the help with this, I'll report back if I have further problems!
__________________
1991 Grand Wagoneer - Hunter Green. All stock. Rebuilt 360 with Melling MTA-1 cam.

1998 Cherokee (XJ) 4.0
1997 Grand Cherokee (ZJ) 4.0
1974 Ford F100 390
Reply With Quote
  #34  
Old 08-21-2020, 01:20 AM
Brynjminjones's Avatar
Brynjminjones Brynjminjones is online now
258 I6
 
Join Date: Jun 11, 2017
Location: Derby, England
Posts: 301
Now the weather over here isn't so hot, I thought I'd report back my findings!

After being parked for several days, the Wagoneer is back to being able to fire right up with no problems at all.

I guess the gas must just have been evaporating really quickly after parking in the garage with a very hot engine bay on a hot day.
I've often noted in the past just how long the engine seems to stay hot for in the garage, so that must have been accelerating the gas evaporation.

It probably doesn't help that my air cleaner doesn't have any of the flaps to seal it off, so it probably vents almost as easily as an open element cleaner.

Thanks again for the help, carburetors are still a learning curve for me!
__________________
1991 Grand Wagoneer - Hunter Green. All stock. Rebuilt 360 with Melling MTA-1 cam.

1998 Cherokee (XJ) 4.0
1997 Grand Cherokee (ZJ) 4.0
1974 Ford F100 390
Reply With Quote
  #35  
Old 08-31-2020, 01:35 AM
FSJunkie's Avatar
FSJunkie FSJunkie is offline
The Nigel Tufnel of the FSJ world.
 
Join Date: Jan 09, 2011
Location: Not The Hot Part, Arizona
Posts: 4,010
The evaporation of fuel from the float bowl varies greatly with ambient temperature and the volatility of the fuel.

It's possible that the fuel you are buying has a high volatility rate that makes it evaporate very quickly. This would be more of a "winter blend" of gas rather than a "summer blend". High volatility fuel in hot weather can create all kinds of problems.

Opening the hood after you shut the engine off will aid greatly in preventing the fuel from evaporating. Most of the evaporation happens within the first few hours of shutdown while it's still very hot under the hood. Opening the hood lets most of that heat out.
__________________
'72 Jeep Wagoneer Custom, 360 V8

I love how arguements end as soon as Ristow comments. Ristow is right...again.
Reply With Quote
  #36  
Old 08-31-2020, 11:47 AM
Brynjminjones's Avatar
Brynjminjones Brynjminjones is online now
258 I6
 
Join Date: Jun 11, 2017
Location: Derby, England
Posts: 301
I expect you might be correct.

I don't know if we use winter blends for fuel here as it very rarely gets below 25F, but since the weather has cooled down from ~90F I've not had another problem with the Wagoneer.

Fingers crossed it was just a very heat soaked engine bay, being parked somewhere it wouldn't cool down quickly.
__________________
1991 Grand Wagoneer - Hunter Green. All stock. Rebuilt 360 with Melling MTA-1 cam.

1998 Cherokee (XJ) 4.0
1997 Grand Cherokee (ZJ) 4.0
1974 Ford F100 390
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Whistle coming from carb or intake -Resolved. jsmorris General FSJ Tech 11 10-08-2015 06:12 PM
Gas leak from front of carb (2150) G_$ General FSJ Tech 4 08-29-2011 11:28 AM
carb draining? Down Yonder General FSJ Tech 0 09-12-2010 11:28 AM
Low and High Carb Adjust - Motorcraft 2150 scotty1998 General FSJ Tech 4 05-15-2008 05:11 PM
2150 Carb Help Needed Doug B. General FSJ Tech 2 03-07-2002 06:20 PM


All times are GMT -6. The time now is 02:21 AM.


Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
corner corner