Hi everyone. I have been using this forum for the past few weeks to try to get my 1965 F250 with a 1974 390 FE running. Most of the problems the seller told me about were electrical. Since I got the truck, I've replaced the ignition switch, starter relay, installed a pertronix ii ignitor, flamethrower coil and bypassed the pink resistor wire. I also did the basic stuff like new plugs, oil, and air cleaner. It was also missing the alternator and regulator so I bought and installed those. I also rebuilt the carburetor.

Anyway, as soon as I turned the key, it fired right up but died almost immediately. I have the timing set as good as I can get it by myself. (It won't idle long enough for me to use the light). I thought my gas might have been bad so I replaced it with fresh 87 octane fed from a 5 gallon can directly to the fuel pump. No change. The only way to keep it running is to close the choke completely and keep it around 1500-1700 rpm (I'm guessing). It runs so smooth at that point that you could balance a coin on it.

(By the way, I used the dowel method to measure the stroke as well as measuring 1 and 4 at TDC. Both measurements came out just over 3 3/4" confirming the 390 I believe.)

I've checked firing order, compression, float level, and I've tried looking for vacuum leaks with carb spray but it's hard to do while I'm working the throttle at the same time. So far, everything has checked out fine.

One thing that really has me stumped it how rich it smells. I thought because it only runs with the choke closed that meant it was lean? I've got the idle mixture screws out 1 1/2 turns on both sides. It just smells like burned gas and the plugs are almost completely matte black. Is that because I have to give it so much gas for it to run? I have to pump it a few times before I start it with the key.

At this point, I'm thinking it has to do with the carburetor. When I bought the truck, I noticed the air cleaner was from a 302 but now I see that it has the 1.08 venturi and 49 size jets. Could that be my problem?

Are the symptoms more indicative of a vacuum leak? The egr and distributor advance are the only 2 vacuum lines I am using right now. All of the other ports are capped off. I've tried running it with the egr and vac advance hooked up and capped off with no change. The pcv seems to be working(it's hooked to a vacuum tree on the intake. I have a vacuum gauge hooked up to the un-used pcv port on the egr plate. It reads steady between 20 and 23 when I have it "idling" at 1500-1700 rpm.

I'd appreciate any help you can give me. I am 22 and this is my first carburated vehicle. I do have prior experience working on cars but they have all been fuel injected and computer controlled so bare with me 😅

(Sorry for the long post)

 

So the choke being closed is going to make the mixture richer. Less air for the gas to mix with.

What you are describing I would suspect a big vacuum leak. Usually the higher rpms help a motor compensate for the leak. For troubleshooting I personally would disconnect and cap off all things vacuum. PCV, dizzy dashpot, brakes (if you have a booster). Then next time you have it running I'd try and find the vacuum leak. I personally prefer the cigar method but that's probably also because I enjoy having cigars....

I would also inspect the egr as they tend to be potential leak sources. it may be stuck open. I'm assuming the egr is in a spacer plate? I'd be tempted if I was you to pull the carb and inspect that. or even try running it without it on there depending on how easy it would be to do.

 

Thanks for the reply!

I will look in to the smoke method this afternoon. I have plugged everything I have with no change so far. Could it be a leak around the intake manifold?

It has the egr spacer plate. I believe it's an early one because it's aluminum. I cleaned it out with carb spray as best as I could when I had the carb off. It was pretty plugged up with carbon. I did try blowing and sucking on the vacuum port on the egr itself. No air passed through in either direction at that point.

I haven't tried running it without the spacer because if it ended up fixing the problem, I'd be too tempted to leave it like that. Unfortunately the distributor is still the original motorcraft I believe, which is curved to run with the egr. Even if I recurved the distributor, I've heard that because of todays fuel, a spacer is necessary for starting and running reasons. If all else fails though, I'm not opposed to trying.

I will get some high temp gasket paper and try re-installing the carb and egr sometime in the next few days. If that doesn't work, I might buy or borrow a good carburetor to see if it will idle or if it still has problems.

 

You are correct about that carb it is a bit small for a 390. A 2 bbl for that engine should have 1.68 throttle bores and 1.21 venturi's.
Do you have the fuel pump with the filter canister on the pump? If so you might want to check the filter. Also a good cleaning and rebuilding the carb might be a good place to start.

 

You are correct that FEs can have leaks at the manifold. So hopefully if that is the case the cigar trick will help it turn up.

I understand the aluminum egr spacers are known to have corrosion issues (not first hand knowledge just something I'm pretty sure I've seen reported for what that is worth). But if you had the carb off and didn't see anything suspect it may be fine. I'm not sure on whether the egr can be tested as shut just by verifying the diaphragm isn't letting air thru. However full disclosure I have personally as a rule always just blocked off or removed the EGR on the carb'd vehicles I've owned.

Usually running a spacer is a good idea to help keep the carb from getting heat soaked by the motor. You can get a phenolic spacer to replace the egr spacer if that does resolve the issue. Assuming you are running the dizzy that is stock with the egr motor I believe you are correct that it will be curved for the egr to be in place. Which I believe usually only becomes an issue towards the end of the curve and having all the timing in. But I may be wrong on that. So definitely check that if you end up going down that route. Though I suppose if the egr is stuck open you might be able to just buy a replacement or repair it.

Side Note: I always feel pretty useless on diagnosing and helping track down issues over the internet. It all feels like it's something that 30 minutes of being there could likely get it working...

 

It had a replacement fuel pump installed at some point. It's the one with the 2 "legs". There is a clear filter that is up by the carb that looks pretty clean.

 

So far, you've been extremely helpful. Here is the post I started in the 1973-1979 forum. https://www.ford-trucks.com/forums/1...l#post19840325

Let me know if you think of anything else I can do in the meantime. Thanks again!

My rpm gauge timing light combo got here early. I was off slightly on my estimate of where it was "idling" with the choke fully closed. I estimated 1500-1700 rpm. According to the gauge, it was 1400 rpm. The timing was almost spot on. I was aiming for 12 degrees but it ended up being at 14 at 750 rpm so I backed it off 2 degrees. (Read below to see how I got it down to 750 rpm)

Today, I wrenched down as hard as I could without stripping the carb bolts. All 4 moved a VERY SLIGHT amount. I added more seafoam to the gas can. And I backed the idle screws out to 3 full turns.

After all of that, I started it up and held the idle with my hand until it came up to temperature (not quite open thermostat). The choke was still shut all the way but I got it to idle down to 750. It was stumbling a bit but otherwise ran well enough that I could let go of the throttle and set the timing.

After setting the timing, I shut it off, backed the idle screws out 4 full turns, fully opened the choke (by now the thermostat had opened), gave it 2 pumps of gas and it idled around 750. There was still a stumble or miss but not too bad. It still smells slightly rich but maybe that's just how these older cars smell.

After that, I sprayed carb spray around the carb. The vacuum gauge was reading steady at 18hg. (Lower than the 21ish from before but I assume that's because of the lower idle and richer idle mixture screws). Anyway, I think the idle slightly jumped when I sprayed around the throttle on the carb. It also slightly jumped when I used the little red straw and sprayed under the egr plate at the back. The rpm didn't shoot way up like I was expecting but it was noticeable enough that it's clearly been the main problem all along and the high idle was hiding it and making it hard to find the vacuum leak because of the fan blowing too fast to get carb spray to specific areas.

I ordered one of those $80 2150 carbs from Amazon just to test it out. It has a 1.14 venturi (opposed to the 1.08 I have now). It may seem kind of dumb but I was told by a friend that they work just as well but don't use the same jet threads so if I need more flow, I'll have to drill them out.

When I was rebuilding the carb, I noticed that the idle mixture screws were "loose" meaning no or little tension. Also, one of the jets was pretty loose so I think the carb body jet threads are stripped. I got these issues somewhat worked out during the rebuild but this core may be toast regardless.

I'll keep everyone updated until this truck gets running good enough that I'd feel comfortable driving it. Until then, any advice would be appreciated!

 

That about sums it up so far. I paid $1000 for this truck 3 weeks ago today. To get it to this point, it's been 30 minute $30 fixes. (About $250 total so far). I have been using previous posts from this forum since I got it but once it got to the point of starting and not running, it always feels like a unique problem 😂. I'm sure anyone with previous experience could've gotten it running and idling smooth very quickly. One day, I think I'll have the experience and not know how to explain it over the internet

 

You will get it going you just need to be methodical and fix one thing at a time. These engine specific forums don't get as much traffic as the vehicle specific forums do. My suggestion is you post your questions in this forum 1961 - 1966 F-100 & Larger F-Series Trucks - Ford Truck Enthusiasts Forums (ford-trucks.com)

If you can you should buy a set of shop manuals for your year truck. Those books will solve a lot of mysteries. They are available new on CD or print and used on E-bay. And if it isn't covered in the book I'll guarantee someone in the 61-66 forum has been there and done it..
I've got to think from your first post that your truck sat for quite awhile not running. You really need to pull the fuel tank and clean it out and flush the lines. Lacquer thinner does a good job of dissolving gummed up fuel and some phosphoric acid will get the rust out.
Good luck young man.

 

Thank you! I will give the lacquer thinner and phosphoric acid a try. Are they okay to soak for a while or do they need to be drained right away?

 

Let the thinner soak awhile slosh it around some. I usually dump in a half gallon at a time until all the gum is out. Hopefully it isn't very rusty inside. Use the acid full strength slosh it around. Don't let it dry inside there. After the rust turns black dump it and rinse it well with water.

 

Thanks!

I just looked. Its still got about a gallon or so of "gas" left in the tank. The previous owner said it sat for 4 years but I don't know if he tried to get it started at any point since then. It smells like it's a few years old. I don't see much rust though.

I'll get to work on the tank later this week. Unfortunately we went from 62 yesterday to snow today.

The tank is behind the seat in the cab. It has "1977" chalked on it. I assume it's from a junkyard and possibly larger than the '65 tank. When the truck is running, the gas gauge doesn't move so either the sender is missing or stuck. While I have the tank out, I'll look into repairing/replacing that

 

Just a quick update for anyone interested:

We are getting snow today so I haven't done much on the truck. I did run it one more time yesterday. I installed the air cleaner and maybe it was just in my head but I think it ran "slightly" better. I guess because the air cleaner restricts air a little more than without.

Anyway, the remanufactured carb should be here early next week. It comes with the thicker gasket but not one for the egr plate to intake. I will get some high temp gasket paper to make a copy of that gasket. I will also take the egr off the spacer, clean it out as best as I can and make a new gasket for it.

In the meantime, I will clean out the gas tank, work on the fuel level sender (not working or missing), check transmission and differential fluid, and other miscellaneous stuff. Thanks again!

 

You really need to start a new thread in the 61-66 forum since the fuel tank an sender aren't engine specific. Guys over there will be glad to answer those types of questions. Just start a new thread and put a link to this one in case anyone wants to read it from the beginning. The King Seeley type gauges in these trucks have a specific order to trouble shoot things so you actually know what isn't working.

 

About an hour or so after I posted this thread, I copied and pasted it into the 1973-1979 forum. Here is the link: https://www.ford-trucks.com/forums/1...th-idle-4.html

The engine and transmission are from a '74 F250 and the tank is from a '77. The guy I got the truck from had it since the early 90's and did all these swaps as necessary to keep the truck on the road. From what I've been told, before the cash for clunkers "deal", parts for 70's trucks were nearly free in the 2000's so that's why I assume he used those parts.

I thought about posting in the 1961-1966 forum but I already had this thread and the one in the 1973-1979 forum. I didn't want to over stay my welcome as soon as I got here. Besides, I'm not sure the egr spacer leak would've been diagnosed as quickly because those trucks didn't have them as far as I know. It seems like it's a very common problem on the 1973-1979 forum so almost immediately a few people pointed to it as a potential vacuum leak source.

Both of these threads have been very helpful and I appreciate all the advice. Thanks again!