The Ford Barn

stouchton · 07-11-2016, 10:16 AM

Acquired a curious issue after sitting the winter, and simply been dealing with it but now inclined to pull carb and clean.

Normally have a very nice idle - but now I realize the slope the car is on greatly effects idle.

Example - garage is absolutely flat. Adjust for perfect idle. Back car out of garage and park on driveway. Now have a rough idle. Driveway has a very slight slope - car will just begin to roll if brake is released.

So I readjust idle outside, drive car in garage and now the idle gets rough again!

So I am pretty sure I've got the angle of fuel in the bowl effecting idle, and the carb has not been apart for a couple years.

Just looking for a couple pointers on where to focus. Might be obvious when I open her up, but thought I would educate myself as much as possible first!

Thanks

Patrick L. · 07-11-2016, 10:27 AM

Hmmm, now there is a wonderment.

Kinda sounds like a float level issue. Maybe just pulling the top will show what is happening.

stouchton · 07-11-2016, 07:14 PM

My neighbors probably thought I was nuts..... must have pulled in and out of garage two dozen times!

Carb is a Zenith, and this will be interesting to explore. I do agree it sounds like a level issue, just not sure if it the main bowl or secondary well. Car runs fine except for idle.....

Chuck Sea/Tac · 07-11-2016, 10:49 PM

If you adjust the gav does it change the idle? If so, then you're idle is too high. Assuming this is stock.

stouchton · 07-12-2016, 10:47 AM

She is idling low enough that GAV has virtually no effect on idle. And she is stock.

I did let her sit the winter with ethanol gas in her

Planning on pulling her apart, doing a good clean and chase the secret passageways. I do have the fuel level 5/8" below the mating line - but I have read a couple posts where folks recommend it being higher??? So I need to research that.

Thanks and take care.

Tom Wesenberg · 07-12-2016, 01:10 PM

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The way ethanol draws moisture, I sure wouldn't let it set over the winter with it in the tank or carb.

stouchton · 07-12-2016, 03:42 PM

Hi Tom - might have learned my lesson on this one

More worried about the tank - would hate for it to start rusting. Unfortunately in my area I cannot avoid ethanol. I did use the new Stabil, but not sure if it lives up to its marketing hype.

700rpm · 07-12-2016, 04:11 PM

Maybe rust or some other foreign material moving in the tank and blocking the outlet hole?

Brentwood Bob · 07-12-2016, 05:34 PM

Take the carb apart and clean it. the idle jet likes to plug up.
Bob

J Franklin · 07-12-2016, 06:43 PM

MMO in the tank will fight rusting. It is the oil in "Snake Oil". It'll keep the valves from gumming up with the corn syrup gas also.

ian Simpson · 07-12-2016, 11:38 PM

The float chamber is ahead of the jet on a Zenith carb. When you back down your driveway the chamber is relatively higher giving the effect of a float set too high. The converse would happen if you backed into your garage. Do not worry about it. Set the
carb for level ground and accept the roughness if the ground moves beneath you.

This is one of the major reasons why fuel injection is superior to carbs. Imagine what happens in high speed aerobatics in a Spitfire!

stouchton · 07-14-2016, 03:23 PM

I know well about the Spitfire - regaled many times by my brother-in-law's father who was a Luftwaffe fighter pilot - Bf109 with the DB601 engine (fuel injection).

However - the slope is slight, and this never happened before. So something is amiss and I am anxious to find out what.

I have been accepting the roughness and rolling along this year - though I got the urge to tinker! So I will take my time and give her a thorough going over. Won't happen for a couple weeks though. I'll post back the findings for the interested minds.

pgerhardt · 07-15-2016, 08:28 AM

Quote:

Originally Posted by ian Simpson

The float chamber is ahead of the jet on a Zenith carb. When you back down your driveway the chamber is relatively higher giving the effect of a float set too high. The converse would happen if you backed into your garage. Do not worry about it. Set the
carb for level ground and accept the roughness if the ground moves beneath you.

This is one of the major reasons why fuel injection is superior to carbs. Imagine what happens in high speed aerobatics in a Spitfire!

Early Spitfires were carbureted. It caused quite a problem when negative G's were encountered during the battle of Brittain. The Bf-109s had fuel injection and no such problems.

Patrick L. · 07-15-2016, 10:06 AM

Most float equipped carbureted aircraft engines have problems in negative maneuvers.

The carbureted Merlin engines were fixed with the 'Tilly restricter'. [ named after the woman inventor].

stouchton · 08-22-2016, 12:01 PM

So... got too busy in life and just pulled the carb off on Sunday.

Disassembled and found absolutely nothing wrong! Clean as a whistle inside.

Chased all the hidden passages, gently blew air through all orifices and passageways and found nothing wrong.

I will soon re-assemble with jets from Renners and see how she runs.

Mitch//pa · 08-22-2016, 12:21 PM

Make sure the throttle shaft has 0 slop

TinCup · 08-22-2016, 12:22 PM

With the B carb Ford changed the float pivot to the side of the bowl which fixed this issue. My Zenith 3 does the same thing on my inclined driveway.

stouchton · 08-22-2016, 12:48 PM

Quote:

Originally Posted by Mitch//pa

Make sure the throttle shaft has 0 slop

Didn't think of that one with the incline!

I've been trying to figure out if it is OK or not. The shaft rotates very easily, but I cannot detect any side to side play in the bore.

Not sure how much play is needed to monkey around with the idle mix.

Would the propane trick be applicable here??

stouchton · 08-22-2016, 12:50 PM

Quote:

Originally Posted by TinCup

With the B carb Ford changed the float pivot to the side of the bowl which fixed this issue. My Zenith 3 does the same thing on my inclined driveway.

What confuses me is that it never seemed to do it before.

Also, most folks think this part of my driveway is flat - it is only slightly inclined. So slight that the car will not always roll - need to push it to get it moving.

Mitch//pa · 08-22-2016, 02:34 PM

If you have 0 side play your good.... Don't worry bout propane checking it...being so close to the air horn it wold prob suck some up and you'll get a false test...

Brentwood Bob · 08-22-2016, 03:25 PM

Take out the throttle shaft and see if there is slop with the butterfly removed.
I was wondering if there is a split in the idle jet tube.
Bob

stouchton · 08-25-2016, 06:26 PM

Fired her up tonight and she idles fine. Possibly a slight change do to incline, but could have been my imagination. It was significant before.

She idled down real low, and very easy to set idle mix. GAV seemed to have more effect at idle than before.

Will need to road test another night

I am curious if she is still OK when coming to a sudden stop.

Not really sure what is different. I did replace all the jets and the secondary well was clean. Not exactly sure of my float level - simply used one gasket to put it level. 2 gaskets dropped it down way too far. Don't have a thin gasket to play with. Too much going on tonight to hook up the site tube.... will do on the weekend.

I guess I might have missed something in the idle jet?

stouchton · 08-27-2016, 08:07 AM

Had a good test drive last night. No stalling when coming to a stop, though the idle did slow on a simulated panic stop.

Sitting downhill (significant grade) at a traffic light the idle did get unhappy and rough - though I can picture in my head how the level in bowl where it feeds the secondary well would have been different.

One good thing from all the in and out of garage driving I did: Noticed when I pulled into the garage I did not have to use the brake to stop. Just pushed in the clutch and the car stopped!

I loosened all the brakes 1 click. Noticeable power difference when you aint draggin' brakes!

07-11-2016, 10:16 AM	#1
stouchton Senior Member Join Date: Jun 2013 Location: Pottstown, PA Posts: 342	Idle being effected by SLIGHT angle! Acquired a curious issue after sitting the winter, and simply been dealing with it but now inclined to pull carb and clean. Normally have a very nice idle - but now I realize the slope the car is on greatly effects idle. Example - garage is absolutely flat. Adjust for perfect idle. Back car out of garage and park on driveway. Now have a rough idle. Driveway has a very slight slope - car will just begin to roll if brake is released. So I readjust idle outside, drive car in garage and now the idle gets rough again! So I am pretty sure I've got the angle of fuel in the bowl effecting idle, and the carb has not been apart for a couple years. Just looking for a couple pointers on where to focus. Might be obvious when I open her up, but thought I would educate myself as much as possible first! Thanks

07-11-2016, 10:27 AM	#2
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Idle being effected by SLIGHT angle! Hmmm, now there is a wonderment. Kinda sounds like a float level issue. Maybe just pulling the top will show what is happening.

07-11-2016, 07:14 PM	#3
stouchton Senior Member Join Date: Jun 2013 Location: Pottstown, PA Posts: 342	Re: Idle being effected by SLIGHT angle! My neighbors probably thought I was nuts..... must have pulled in and out of garage two dozen times! Carb is a Zenith, and this will be interesting to explore. I do agree it sounds like a level issue, just not sure if it the main bowl or secondary well. Car runs fine except for idle.....

07-11-2016, 10:49 PM	#4
Chuck Sea/Tac Senior Member Join Date: May 2010 Location: Between Seattle & Tacoma Posts: 2,354	Re: Idle being effected by SLIGHT angle! If you adjust the gav does it change the idle? If so, then you're idle is too high. Assuming this is stock.

07-12-2016, 10:47 AM	#5
stouchton Senior Member Join Date: Jun 2013 Location: Pottstown, PA Posts: 342	Re: Idle being effected by SLIGHT angle! She is idling low enough that GAV has virtually no effect on idle. And she is stock. I did let her sit the winter with ethanol gas in her Planning on pulling her apart, doing a good clean and chase the secret passageways. I do have the fuel level 5/8" below the mating line - but I have read a couple posts where folks recommend it being higher??? So I need to research that. Thanks and take care.

07-12-2016, 01:10 PM	#6
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Idle being effected by SLIGHT angle! Sponsored Links (Register now to hide all advertisements) The way ethanol draws moisture, I sure wouldn't let it set over the winter with it in the tank or carb.

07-12-2016, 03:42 PM	#7
stouchton Senior Member Join Date: Jun 2013 Location: Pottstown, PA Posts: 342	Re: Idle being effected by SLIGHT angle! Hi Tom - might have learned my lesson on this one More worried about the tank - would hate for it to start rusting. Unfortunately in my area I cannot avoid ethanol. I did use the new Stabil, but not sure if it lives up to its marketing hype.

07-12-2016, 04:11 PM	#8
700rpm Senior Member Join Date: May 2010 Location: Portland, Oregon Posts: 5,903	Re: Idle being effected by SLIGHT angle! Maybe rust or some other foreign material moving in the tank and blocking the outlet hole? __________________ Ray Horton, Portland, OR As you go through life, keep your eye on the donut, not the hole.

07-12-2016, 05:34 PM	#9
Brentwood Bob Senior Member Join Date: May 2010 Location: brentwood, ca Posts: 4,244	Re: Idle being effected by SLIGHT angle! Take the carb apart and clean it. the idle jet likes to plug up. Bob

07-12-2016, 06:43 PM	#10
J Franklin Senior Member Join Date: May 2010 Location: Oregon Posts: 5,963	Re: Idle being effected by SLIGHT angle! MMO in the tank will fight rusting. It is the oil in "Snake Oil". It'll keep the valves from gumming up with the corn syrup gas also. Last edited by J Franklin; 07-12-2016 at 06:57 PM.

07-12-2016, 11:38 PM	#11
ian Simpson Senior Member Join Date: Apr 2014 Posts: 709	Re: Idle being effected by SLIGHT angle! The float chamber is ahead of the jet on a Zenith carb. When you back down your driveway the chamber is relatively higher giving the effect of a float set too high. The converse would happen if you backed into your garage. Do not worry about it. Set the carb for level ground and accept the roughness if the ground moves beneath you. This is one of the major reasons why fuel injection is superior to carbs. Imagine what happens in high speed aerobatics in a Spitfire!

07-14-2016, 03:23 PM	#12
stouchton Senior Member Join Date: Jun 2013 Location: Pottstown, PA Posts: 342	Re: Idle being effected by SLIGHT angle! I know well about the Spitfire - regaled many times by my brother-in-law's father who was a Luftwaffe fighter pilot - Bf109 with the DB601 engine (fuel injection). However - the slope is slight, and this never happened before. So something is amiss and I am anxious to find out what. I have been accepting the roughness and rolling along this year - though I got the urge to tinker! So I will take my time and give her a thorough going over. Won't happen for a couple weeks though. I'll post back the findings for the interested minds.

07-15-2016, 10:06 AM	#14
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Idle being effected by SLIGHT angle! Most float equipped carbureted aircraft engines have problems in negative maneuvers. The carbureted Merlin engines were fixed with the 'Tilly restricter'. [ named after the woman inventor].

08-22-2016, 12:01 PM	#15
stouchton Senior Member Join Date: Jun 2013 Location: Pottstown, PA Posts: 342	Re: Idle being effected by SLIGHT angle! So... got too busy in life and just pulled the carb off on Sunday. Disassembled and found absolutely nothing wrong! Clean as a whistle inside. Chased all the hidden passages, gently blew air through all orifices and passageways and found nothing wrong. I will soon re-assemble with jets from Renners and see how she runs.

08-22-2016, 12:21 PM	#16
Mitch//pa BANNED Join Date: May 2010 Location: Bucks County, PA Posts: 11,454	Re: Idle being effected by SLIGHT angle! Make sure the throttle shaft has 0 slop

08-22-2016, 12:22 PM	#17
TinCup Senior Member Join Date: May 2010 Location: OKC / Tonkawa, Ok. Posts: 1,977	Re: Idle being effected by SLIGHT angle! With the B carb Ford changed the float pivot to the side of the bowl which fixed this issue. My Zenith 3 does the same thing on my inclined driveway. __________________ Oklahoma City Model A Restorers Group.

08-22-2016, 02:34 PM	#20
Mitch//pa BANNED Join Date: May 2010 Location: Bucks County, PA Posts: 11,454	Re: Idle being effected by SLIGHT angle! If you have 0 side play your good.... Don't worry bout propane checking it...being so close to the air horn it wold prob suck some up and you'll get a false test...

08-22-2016, 03:25 PM	#21
Brentwood Bob Senior Member Join Date: May 2010 Location: brentwood, ca Posts: 4,244	Re: Idle being effected by SLIGHT angle! Take out the throttle shaft and see if there is slop with the butterfly removed. I was wondering if there is a split in the idle jet tube. Bob

08-25-2016, 06:26 PM	#22
stouchton Senior Member Join Date: Jun 2013 Location: Pottstown, PA Posts: 342	Re: Idle being effected by SLIGHT angle! Fired her up tonight and she idles fine. Possibly a slight change do to incline, but could have been my imagination. It was significant before. She idled down real low, and very easy to set idle mix. GAV seemed to have more effect at idle than before. Will need to road test another night I am curious if she is still OK when coming to a sudden stop. Not really sure what is different. I did replace all the jets and the secondary well was clean. Not exactly sure of my float level - simply used one gasket to put it level. 2 gaskets dropped it down way too far. Don't have a thin gasket to play with. Too much going on tonight to hook up the site tube.... will do on the weekend. I guess I might have missed something in the idle jet?

08-27-2016, 08:07 AM	#23
stouchton Senior Member Join Date: Jun 2013 Location: Pottstown, PA Posts: 342	Re: Idle being effected by SLIGHT angle! Had a good test drive last night. No stalling when coming to a stop, though the idle did slow on a simulated panic stop. Sitting downhill (significant grade) at a traffic light the idle did get unhappy and rough - though I can picture in my head how the level in bowl where it feeds the secondary well would have been different. One good thing from all the in and out of garage driving I did: Noticed when I pulled into the garage I did not have to use the brake to stop. Just pushed in the clutch and the car stopped! I loosened all the brakes 1 click. Noticeable power difference when you aint draggin' brakes!