The Ford Barn

Bruce_MO · 09-12-2012, 07:44 PM

I have a '53 flathead with two 94 carbs on an Offenhauser intake, and the car starts immediately after a half-turn when cold, or if I try it immediately after shutting it off after it's warmed up. But if I let is sit for 5 minutes to a couple hours and then try it, it's really hard to start and I have to eventually floor it to hold the butterflies open before it'll start after 10-15 seconds of cranking. So I have assumed it's flooding from leaking power valves. I've replaced them a couple times; the last time with valves from a known flathead carb supplier who claims to machine them at the gasket face so they won't leak. With that suppler's help, I have dialed in the right jets and PV sizes and it runs great, but it seems that the hot-shutbown leakage problem remains. Could it be something else? Is it worth shutting the engine off and taking the carb tops off to see if one of the bowls have drained down to find a leaker? Any ideas would be appreciated. Thanks

flatjack9 · 09-12-2012, 07:57 PM

When you shut the hot engine off, the fuel will tend to boil over into the intake manifold and in essence flood the engine. Get some insulating spacers to put under the carbs to alleviate this problem. When starting, crank the engine and immediately open the throttle all the way. Not a power valve problem.

jake197000 · 09-12-2012, 08:01 PM

if they were leaking it would probablyload up at idle after you got it started because thed leak worse with vacuum acting on them.could be float/level carbs may need insulating spacers.

Charlie ny · 09-12-2012, 08:33 PM

Bruce,
I think that supplier guy might be me. I'm pretty sure Jack and Jake are on
the right path ,if however your troubles continue after taking their advice I will do
all in my power to make your car and you happy.
Charlie ny

bige386 · 09-12-2012, 09:02 PM

I went through the same problem with my 46 239 and it wasn't the carbs like I thought. It ended up being the coil. Do you run a modern style coil or an original ? My car would start just fine cold or right after shutting down it would start right up but if it sat any period of time after shutting it down ya might as well for get about it. The modern style coil would get hot and break down and lose spark at the plug. Not enough to fire the car back up. I did like you are doing now going through the carb with no change. I finally installed a new coil from Skip and have not had any problems with my car what so ever. I put on nearly 300 mile this past week end flawlessly.
Something to think about.

Bruce_MO · 09-13-2012, 06:53 AM

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Gentlemen,

Thank you for your excellent suggestions and insights. Regarding the insulation, would an additional one or two gaskets work, or would you suggest something else?

Regarding the coil possibly being the problem...yes, it's a modern NAPA coil. I'll try swapping coils with the one on my '51 that has no starting issues of any kind.

Thanks again for your help...I greatly appreciate you taking the time to share your thoughts

bige386 · 09-13-2012, 03:39 PM

Keep an eye out on ebay. Now and then an original coil pops up on there or you could contact Skip Haney and I'm sure he could hook you up with one of his coils. They work great. I have one o my car and couldn't be happier with it.

GreenMonster48 · 09-13-2012, 04:22 PM

Does it smell like gas when it starts hard? Sometimes if the timing is advanced to far it will do a 'hot start' and crank over laboriously...

09-12-2012, 07:44 PM	#1
Bruce_MO Senior Member Join Date: May 2010 Posts: 433	Hard starting- power valve problem? I have a '53 flathead with two 94 carbs on an Offenhauser intake, and the car starts immediately after a half-turn when cold, or if I try it immediately after shutting it off after it's warmed up. But if I let is sit for 5 minutes to a couple hours and then try it, it's really hard to start and I have to eventually floor it to hold the butterflies open before it'll start after 10-15 seconds of cranking. So I have assumed it's flooding from leaking power valves. I've replaced them a couple times; the last time with valves from a known flathead carb supplier who claims to machine them at the gasket face so they won't leak. With that suppler's help, I have dialed in the right jets and PV sizes and it runs great, but it seems that the hot-shutbown leakage problem remains. Could it be something else? Is it worth shutting the engine off and taking the carb tops off to see if one of the bowls have drained down to find a leaker? Any ideas would be appreciated. Thanks

09-12-2012, 07:57 PM	#2
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,526	Re: Hard starting- power valve problem? When you shut the hot engine off, the fuel will tend to boil over into the intake manifold and in essence flood the engine. Get some insulating spacers to put under the carbs to alleviate this problem. When starting, crank the engine and immediately open the throttle all the way. Not a power valve problem.

09-12-2012, 08:01 PM	#3
jake197000 Senior Member Join Date: Sep 2010 Posts: 350	Re: Hard starting- power valve problem? if they were leaking it would probablyload up at idle after you got it started because thed leak worse with vacuum acting on them.could be float/level carbs may need insulating spacers.

09-12-2012, 08:33 PM	#4
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: Hard starting- power valve problem? Bruce, I think that supplier guy might be me. I'm pretty sure Jack and Jake are on the right path ,if however your troubles continue after taking their advice I will do all in my power to make your car and you happy. Charlie ny

09-12-2012, 09:02 PM	#5
bige386 Senior Member Join Date: May 2010 Posts: 264	Re: Hard starting- power valve problem? I went through the same problem with my 46 239 and it wasn't the carbs like I thought. It ended up being the coil. Do you run a modern style coil or an original ? My car would start just fine cold or right after shutting down it would start right up but if it sat any period of time after shutting it down ya might as well for get about it. The modern style coil would get hot and break down and lose spark at the plug. Not enough to fire the car back up. I did like you are doing now going through the carb with no change. I finally installed a new coil from Skip and have not had any problems with my car what so ever. I put on nearly 300 mile this past week end flawlessly. Something to think about. __________________ The Lord is the light--allow Him to guide you.

09-13-2012, 06:53 AM	#6
Bruce_MO Senior Member Join Date: May 2010 Posts: 433	Re: Hard starting- power valve problem? Sponsored Links (Register now to hide all advertisements) Gentlemen, Thank you for your excellent suggestions and insights. Regarding the insulation, would an additional one or two gaskets work, or would you suggest something else? Regarding the coil possibly being the problem...yes, it's a modern NAPA coil. I'll try swapping coils with the one on my '51 that has no starting issues of any kind. Thanks again for your help...I greatly appreciate you taking the time to share your thoughts

09-13-2012, 03:39 PM	#7
bige386 Senior Member Join Date: May 2010 Posts: 264	Re: Hard starting- power valve problem? Keep an eye out on ebay. Now and then an original coil pops up on there or you could contact Skip Haney and I'm sure he could hook you up with one of his coils. They work great. I have one o my car and couldn't be happier with it. __________________ The Lord is the light--allow Him to guide you.

09-13-2012, 04:22 PM	#8
GreenMonster48 Senior Member Join Date: May 2010 Location: Enfield Connecticut Posts: 559	Re: Hard starting- power valve problem? Does it smell like gas when it starts hard? Sometimes if the timing is advanced to far it will do a 'hot start' and crank over laboriously...