I have an 85 F350 with the 460 (7.5L) and the carb is leaking gas past the throttle shaft. I have no idea why there is that much fuel there, but there is. The truck also hesitates on acceleration. It starts to go, then feels like it almost dies, then picks back up and is fine. The truck has a total of 55k miles and the carb was supposed to be rebuilt in '97.

My question is: What are my carb replacement options? I'm pretty sure i have a 4180, so would the (non-emissions) 4160 be a good choice? I'm not planning any power upgrades, just want to keep the truck running and towing at it's peak...

 

Sounds like the power valve is leaking. And, if that is true the normally thirsty 460 will be guzzling.

As for changing carbs, you can go with another Holley like the 4160, but that carb may not be even as fuel efficient as the 4180 and it still uses power valves. You'd probably be better off getting yours fixed. Another approach is an Edelbrock 1406, which is jetted for economy, or the 1405 that is jetted for power. (I'm an Edelbrock guy as I don't like the problems, like the power valve, that the Holleys have.)

 

Thanks for the speedy reply. I was reading another thread here about a guy who had a similar problem (gas leaking by the throttle shaft) and a replacement power valve fixed it.

I'm going to get a kit and rebuild it and go from there. $50 is a lot better than $350+...

If that doesn't fix it the local parts store stocks a Edelbrock carb, but i'd have to look at what part number.

 

Lavatan is one user on here that is running an Edelbrock on his 460. You might PM him for his input, but I know he's had good luck with the carb. The 1405 and 1406 are 600 CFM carbs, but unless you are winding the 460 up, should work well for you.

Take this with a grain of salt because I'm biased, but I have a 351M that I bought with a 4160 Holley on it. The thing wouldn't idle quite right, blubbered at 30 MPH, turned in 12 MPG, but ran WELL when the throttle was planted. I rebuilt the carb and there was no change, but I did discover that the 1460 had stock jetting in it. Then I installed an Edelbrock 1406 and noticed that I could adjust the idle better and that it was much crisper off-idle. Around town it didn't blubber, and I got 14 MPG on the highway. But, when nailed it just didn't have quite the same GO as the Holley. However, I don't need the GO as much as I do the cleaner running and better MPG. And, if I did I'd bolt the 1405 Edelbrock on, the one that is jetted for power.

Anyway, I run Edelbrocks because they work out of the box for me and I don't have blown power valves because they don't have them. I don't have leaking accelerator pumps. And I don't have leaking bowl gaskets. All of which are problems I've experienced with Holleys. But, there are people on here, several of which have more experience with carbs than I have, who like Holleys. So, again, realize that I am biased.

 

If it has been 16 years since the carb was rebuilt, I would say it needs a good rebuild

now. Do it correctly and use a good kit and the carb will perform well for you.

 

Thanks for the help guys. I'll try to remember to report back with news after the rebuild.

 

If you do end up wanting to purchase a new carb, take a good long look at the autolite 4100s. They are fantastic carbs and are extremely easy to tune and rebuild. They are highly sought after by the offroad community because they run so darn well when the trails get choppy, and they will run at angles that you'd never dream of with your standard Edelbrock or Holley carbs.

Give me an autolite 4100 over any Holley or Edelbrock for my truck.

 

Buy the rebuild kit from holley and she will run happy and reliably. A cheap rebuild kit will blow out more than just the powervalve. Good luck

 

Houston, we may have a problem....

I pulled the carb and noticed that someone (not me) and removed the lead plugs for the primary idle screws and the screws are NOT set the same... Here are pictures of how far they stick out...





Can i get these set right again, or an i better off with a new carb?


Also, several of the air bleeds on the secondary side are plugged with a sticky substance, and i had a couple of bad/leaking vacuum caps.

 

Try screwing the idle mix screws all the way in, gently, and see if they stick out the same then. BUT, AS YOU DO IT COUNT THE TURNS. My guess is that someone has just mis-adjusted it and the balance is way off. But, it is possible that someone has replaced one with the wrong type - but even if that has happened you can fix it since you can buy the replacement screws.

The reason for counting the turns is that you should add the counts up, divide by two, and then put both of them at that count when you put it back together. You know that you are going to have to tune the idle, but that gives you a good starting point - assuming that it was properly tuned at one point.

 

I found a procedure for the 4160 that said to turn the screws in all the way in then back them out 1.5 turns as a starting point. Is this about what you're suggesting?

 

Yes, with the exception of going with 1/2 of the sum of how far the two are out. But it makes very little difference as you should wind up at the same place, max vacuum, regardless of where you start.

However, make sure that those screws are right-hand threaded. IIRC, there were some Holleys that were left-hand threaded. So, while you are playing with it check that out just to make sure.

 

I'll keep it in mind. This thing is filthy..It's a wonder it ran at all...

 

I use O'Reilly's house brand brake cleaner on everything, inc carbs. But, not all brake cleaners are created equal. Someone brought another brand to my shop and the first thing we noticed is that it smelled like licorice. Second was that very little happened in the cleaning arena. I brought out the O'Reilly's and the cleaning started.

 

Good to know since that would be the brand i got. I love my local O'Reilly's and i get a discount with my work acct.

Why brake cleaner instead of carb cleaner?