The Ford Barn

Flathead86 · 05-04-2020, 06:25 PM

Hi guys, I am lost, I’ve tried everything and can’t get my flathead to idle right, it’s spitting from the exhaust, like a soft back fire, I’ve tried Adjusting my timing, can’t really adjust my dual carbs bs of this issue, what you think might be the problem, any advice would be great? Thanks

petehoovie · 05-04-2020, 06:30 PM

Sticking valves....Drizzle some MMO down the carb at fast idle (out in the sticks someplace) and add some to the gas tank....

Flathead86 · 05-04-2020, 06:33 PM

[QUOTE=petehoovie;1883510]Sticking valves....Drizzle some MMO down the carb at fast idle (out in the sticks someplace) and add some to the gas tank....[/QUOT

It’s a fresh engine built,

petehoovie · 05-04-2020, 06:40 PM

It could still be a valve hanging up or maybe its that nasty cam you put in it....

Flathead86 · 05-04-2020, 06:43 PM

Quote:

Originally Posted by petehoovie

It could still be a valve hanging up or maybe its that nasty cam you put in it....

What about the cam, it’s a race cam, form h and h flatheads?

petehoovie · 05-04-2020, 06:46 PM

Sponsored Links (Register now to hide all advertisements)

"race cam"? Race cams don't idle like a stock cam....they don't idle so smooth
Tell us about the build and the cam....

Flathead86 · 05-04-2020, 06:54 PM

Quote:

Originally Posted by petehoovie

"race cam"? Race cams don't idle like a stock cam....they don't idle so smooth
Tell us about the build and the cam....

It’s 80 over, Navarro heads, bubbas gmc distributor, dual 97, adjustable lifters, what else would you like to know, the cam is 3/4

my4dv8 · 05-04-2020, 06:57 PM

We need to know exactly the specs of the cam . Just a race cam from H&H is not sufficient info. How does it sound when sped up to say 1800 rpm??

Flathead86 · 05-04-2020, 06:59 PM

Quote:

Originally Posted by my4dv8

We need to know exactly the specs of the cam . Just a race cam from H&H is not sufficient info. How does it sound when sped up to say 1800 rpm??

I can’t really hear the engine right with it spitting like that, but it’s sounds nice,

KiWinUS · 05-04-2020, 07:03 PM

https://youtu.be/SXvnDP25924
Bryan he needs one of these cams
Cheers

KiWinUS · 05-04-2020, 07:09 PM

I suggest a leak down test or at least a compression test. Have you double checked valve lash.

Flathead86 · 05-04-2020, 07:14 PM

Quote:

Originally Posted by KiWinUS

I suggest a leak down test or at least a compression test. Have you double checked valve lash.

All 8 cylinder have more than 100psi I haven’t done a leak down test yet but that’s my next step,

KiWinUS · 05-04-2020, 07:22 PM

Look at plugs if they are black & sooty that will cause your issue. Carbs or too much fuel pressure could cause plugs to be this way.
Have you asked Mike at H&H for his opinion.

Flathead86 · 05-04-2020, 07:25 PM

Quote:

Originally Posted by KiWinUS

Look at plugs if they are black & sooty that will cause your issue. Carbs or too much fuel pressure could cause plugs to be this way.
Have you asked Mike at H&H for his opinion.

My plugs are black, but I can’t adjust my carbs with this problems,

Flathead86 · 05-04-2020, 07:29 PM

Quote:

Originally Posted by Flathead86

My plugs are black, but I can’t adjust my carbs with this problems,

Mike told me it could be carbs, or timing but I feel my timing is right and I just rebuilt the carbs,

KiWinUS · 05-04-2020, 07:41 PM

Okay if plugs are black there’s a carb issue but there’s no adjusting of idle screws that will fix it. Carbs build correctly with correct fuel pressure should not soot plugs no matter where idle screws are. Start idle screws 3/4 to 1 1/4 turns out both same. Them black plugs won’t fix themselves. Need to glass bead or replace or will continue to misfire.

Talkwrench · 05-05-2020, 01:04 AM

Carb leaking down ..?

chap52 · 05-05-2020, 07:14 AM

I would close down one carb totally and see how it runs on one carb. Then get a uni-sync and go through the dual carb sequence. Worked for me years ago with a 3/4 cam, dual 94's. Chap

Flathead86 · 05-06-2020, 10:38 PM

Where would you guys have your timing at? Considering it has a race cam?

tubman · 05-07-2020, 03:59 AM

On a modified engine, I use a vacuum gauge to set initial timing. Get it as close as you can, and then adjust the timing until you get the highest vacuum reading at idle. Then retard it just a small amount and you should be all set.

You're not done yet. This will produce the correct timing at idle, but really has nothing to do with timing at higher rpm's. That depends on the advance curve in the distributor. That is another subject entirely.

05-04-2020, 06:25 PM	#1
Flathead86 Junior Member Join Date: Jan 2018 Posts: 24	Flathead doesn’t idle right Hi guys, I am lost, I’ve tried everything and can’t get my flathead to idle right, it’s spitting from the exhaust, like a soft back fire, I’ve tried Adjusting my timing, can’t really adjust my dual carbs bs of this issue, what you think might be the problem, any advice would be great? Thanks

05-04-2020, 06:30 PM	#2
petehoovie Senior Member Join Date: May 2015 Posts: 8,137	Re: Flathead doesn’t idle right Sticking valves....Drizzle some MMO down the carb at fast idle (out in the sticks someplace) and add some to the gas tank.... __________________ The only thing nice about being imperfect is the joy it brings to others.... *"Silver rings, your butt! Them's washers!"* "We shot our way out of that town for a dollar's worth of steel holes!" - from 'The Wild Bunch' - 1969 https://www.youtube.com/watch?v=7NReUd2_0u0

05-04-2020, 06:33 PM	#3
Flathead86 Junior Member Join Date: Jan 2018 Posts: 24	Re: Flathead doesn’t idle right [QUOTE=petehoovie;1883510]Sticking valves....Drizzle some MMO down the carb at fast idle (out in the sticks someplace) and add some to the gas tank....[/QUOT It’s a fresh engine built,

05-04-2020, 06:40 PM	#4
petehoovie Senior Member Join Date: May 2015 Posts: 8,137	Re: Flathead doesn’t idle right It could still be a valve hanging up or maybe its that nasty cam you put in it.... __________________ The only thing nice about being imperfect is the joy it brings to others.... *"Silver rings, your butt! Them's washers!"* "We shot our way out of that town for a dollar's worth of steel holes!" - from 'The Wild Bunch' - 1969 https://www.youtube.com/watch?v=7NReUd2_0u0

05-04-2020, 06:46 PM	#6
petehoovie Senior Member Join Date: May 2015 Posts: 8,137	Re: Flathead doesn’t idle right Sponsored Links (Register now to hide all advertisements) "race cam"? Race cams don't idle like a stock cam....they don't idle so smooth Tell us about the build and the cam.... __________________ The only thing nice about being imperfect is the joy it brings to others.... *"Silver rings, your butt! Them's washers!"* "We shot our way out of that town for a dollar's worth of steel holes!" - from 'The Wild Bunch' - 1969 https://www.youtube.com/watch?v=7NReUd2_0u0

05-04-2020, 06:57 PM	#8
my4dv8 Senior Member Join Date: Aug 2010 Location: New Zealand Posts: 1,111	Re: Flathead doesn’t idle right We need to know exactly the specs of the cam . Just a race cam from H&H is not sufficient info. How does it sound when sped up to say 1800 rpm??

05-04-2020, 07:03 PM	#10
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 2,960	Re: Flathead doesn’t idle right https://youtu.be/SXvnDP25924 Bryan he needs one of these cams Cheers

05-04-2020, 07:09 PM	#11
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 2,960	Re: Flathead doesn’t idle right I suggest a leak down test or at least a compression test. Have you double checked valve lash.

05-04-2020, 07:22 PM	#13
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 2,960	Re: Flathead doesn’t idle right Look at plugs if they are black & sooty that will cause your issue. Carbs or too much fuel pressure could cause plugs to be this way. Have you asked Mike at H&H for his opinion.

05-04-2020, 07:41 PM	#16
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 2,960	Re: Flathead doesn’t idle right Okay if plugs are black there’s a carb issue but there’s no adjusting of idle screws that will fix it. Carbs build correctly with correct fuel pressure should not soot plugs no matter where idle screws are. Start idle screws 3/4 to 1 1/4 turns out both same. Them black plugs won’t fix themselves. Need to glass bead or replace or will continue to misfire.

05-05-2020, 01:04 AM	#17
Talkwrench Senior Member Join Date: Aug 2012 Location: Perth, Western Australia Posts: 2,687	Re: Flathead doesn’t idle right Carb leaking down ..? __________________ *"Came too close to dying to stop living now!"*

05-05-2020, 07:14 AM	#18
chap52 Senior Member Join Date: Jun 2013 Location: Marana Arizona Posts: 1,776	Re: Flathead doesn’t idle right I would close down one carb totally and see how it runs on one carb. Then get a uni-sync and go through the dual carb sequence. Worked for me years ago with a 3/4 cam, dual 94's. Chap

05-06-2020, 10:38 PM	#19
Flathead86 Junior Member Join Date: Jan 2018 Posts: 24	Re: Flathead doesn’t idle right Where would you guys have your timing at? Considering it has a race cam?

05-07-2020, 03:59 AM	#20
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,316	Re: Flathead doesn’t idle right On a modified engine, I use a vacuum gauge to set initial timing. Get it as close as you can, and then adjust the timing until you get the highest vacuum reading at idle. Then retard it just a small amount and you should be all set. You're not done yet. This will produce the correct timing at idle, but really has nothing to do with timing at higher rpm's. That depends on the advance curve in the distributor. That is another subject entirely.