Resurgence of a F100

6speedsd · Jun 11, 2017

Talked to Summit briefly this evening about the carb tuning. They had all sorts of connection issues and I got tired of being disconnected (they said it was on their end). Jet sizes currently are 67 on primaries, 73 on secondaries. I told him my issue, and he would only suggest buying a smaller carb. Said jetting down isn't going to help my issue, which I disagree with. But, at least I know what size is in it now. I don't really see a need to fool with secondaries as it pulls good once you get in it. Lower rpms, lower pedal is where I'm rich.

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5ninef250 · Jun 13, 2017

Used carb? Have you checked the power valve? Hopefully these questions haven't been asked previously...

6speedsd · Jun 13, 2017

Brand new carb when I bolted it on.

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5ninef250 · Jun 13, 2017

Hmm. I ran a summit carb out of the box on a cammed 302 and I was impressed, it ran well with just tweaks with a vacuum gage. You could make sure the power valve doesn't have a defect and is seated properly.

6speedsd · Jun 13, 2017

I've already done the usual vacuum gauge tweaks. It was set pretty good out of the box, aside from the accelerator pump cam being tight.

It quit on me on the way home this evening. Pulled up to a traffic light, the idle got rough and it shut off. Couldn't get it to fire, but got a lot of smoke out the tailpipe and it stank of raw fuel. I'm thinking my primary float stuck open. I couldn't see any fuel in the front sight window, so I started taking lines loose at random points...before and after regulator, before and after filter...just to make sure I had fuel at those points, and I did. I think the bowl was full and that's why I couldn't see a fuel level. Finally got in and put it on the floor while cranking and it rolled into a start. Missed a bit then cleared up. Drove it the rest of the way home, and it sat there idling in my driveway like nothing had happened. Fuel level half way in sight glass as it should be. That's all I can figure happened....float stuck open for some reason.

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6speedsd · Jun 20, 2017

You guys like Edelbrock carbs? I know they don't have the tuneability of a Holley, but I've never ran one. I'm about to drop to something like a 450cfm I think. I'm tired of fighting this thing. I'll save the 600 for when I build a stroker.

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lincolnlocker · Jun 20, 2017

6speedsd said:
I've already done the usual vacuum gauge tweaks. It was set pretty good out of the box, aside from the accelerator pump cam being tight.

It quit on me on the way home this evening. Pulled up to a traffic light, the idle got rough and it shut off. Couldn't get it to fire, but got a lot of smoke out the tailpipe and it stank of raw fuel. I'm thinking my primary float stuck open. I couldn't see any fuel in the front sight window, so I started taking lines loose at random points...before and after regulator, before and after filter...just to make sure I had fuel at those points, and I did. I think the bowl was full and that's why I couldn't see a fuel level. Finally got in and put it on the floor while cranking and it rolled into a start. Missed a bit then cleared up. Drove it the rest of the way home, and it sat there idling in my driveway like nothing had happened. Fuel level half way in sight glass as it should be. That's all I can figure happened....float stuck open for some reason.

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oh dam.. yeah, i would say it is a sticky float but being new, i wouldnt think it would.. but i have seen wierder chit happen..

6speedsd said:
You guys like Edelbrock carbs? I know they don't have the tuneability of a Holley, but I've never ran one. I'm about to drop to something like a 450cfm I think. I'm tired of fighting this thing. I'll save the 600 for when I build a stroker.

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i dont care for the edelbrocks myself.. lots like them and say they are simpler but i could never get them right..

there should be no reason that you couldn't make that 600 run the way it should..

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psduser1 · Jun 20, 2017

6speedsd said:
I've already done the usual vacuum gauge tweaks. It was set pretty good out of the box, aside from the accelerator pump cam being tight.

It quit on me on the way home this evening. Pulled up to a traffic light, the idle got rough and it shut off. Couldn't get it to fire, but got a lot of smoke out the tailpipe and it stank of raw fuel. I'm thinking my primary float stuck open. I couldn't see any fuel in the front sight window, so I started taking lines loose at random points...before and after regulator, before and after filter...just to make sure I had fuel at those points, and I did. I think the bowl was full and that's why I couldn't see a fuel level. Finally got in and put it on the floor while cranking and it rolled into a start. Missed a bit then cleared up. Drove it the rest of the way home, and it sat there idling in my driveway like nothing had happened. Fuel level half way in sight glass as it should be. That's all I can figure happened....float stuck open for some reason.

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Maybe some trash in the tank? I always ran a cheap filter in front of the pump- 100-200 micron is plenty.

6speedsd · Jun 20, 2017

I have a billet filter on it now. Had intentions of pulling it apart last weekend and seeing if there was trash on the filter element, but it rained most of the weekend. Maybe this weekend I'll get time to fool with it.

I drove it today...no issues at all. Only got like 10mpg last tank for some reason (just shy of 10 actually). Been getting 12.5-13 every tank before that one.

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dsberman94 · Jun 20, 2017

Sounds better now. Same reason mileage on my truck always sucks.

79jasper · Jun 20, 2017

I used to have vapor lock issues with a 79 Chevy. Don't know what caused it. I would just take the line into the carb loose and let the electric pump run.
Ended up swapping a diesel in and ran a bed tank.

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rusty1161 · Jun 20, 2017

Can some of your carb issues be fuel? Do you have the ethanol blend in your area?

Here is an interesting article http://www.militarytrader.com/milit...e-field-ethanol-vapor-lock-and-other-gas-woes

Great truck and project!

Rusty

6speedsd · Jun 21, 2017

I don't think I'm having that issue. I can't say that I've ever really experienced any problems that would point to vapor lock. I really think the stall last week was a stuck float (even though the carb only has less than 1000 miles on it). Once I get the filter pulled and apart I'll know more I think. Thanks for the suggestions though....that never crossed my mind.

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6speedsd · Jun 23, 2017

Any of you guys ever ran the Summit electric fuel pump? Most of the reviews talk about how loud it is. I'm curious if it really is that loud, or if people are just overly dramatic.

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lincolnlocker · Jun 24, 2017

6speedsd said:
Any of you guys ever ran the Summit electric fuel pump? Most of the reviews talk about how loud it is. I'm curious if it really is that loud, or if people are just overly dramatic.

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is there such thing as a quiet electric inline fuel pump? lol

those little carter pumps are reliable and come with a decent mounting setup.. add some more rubber and can barely hear them.. and they are pre set to like 6psi

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6speedsd · Jun 24, 2017

Of course they aren't quiet. But most reviews said you could hear them over open headers (which I find quite hard to believe), or you could hear it in the car with the windows down and radio going while driving down the highway. I'm assuming most are just being overly dramatic, but still. If they are that loud I want no part of it. I've been around vehicles with an electric pump...I know they make some noise, but hearing over the exhaust?

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mandkole · Jun 24, 2017

You'd be much happier with a nice mechanical pump on a street car. The electrics are all pretty noisy. I've got a Holley blue pump and you definitely hear it over the flow 40s that stop at the axle.

6speedsd · Jun 24, 2017

It's really that loud huh! Guess I'll keep my mechanical then.

Forgot to mention....
I pulled the filter apart today. Had some trash on it. I put another 100 micron glass filter between the pump and regulator so I can easily keep an eye on what's going through the line.

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