I have an 84 f150 with a 351 4 b It leaks and the kit to replace it is $75. I need some advise should I rebuild it, or replace it? If I replace it should I get the same one or should I get a different type or model? Someone has bypassed the pump via fan belt.

Thanks Mike

 

How is the rest of the carb, and where is it leaking? I know on the 2 b's you can change acell pump diaphragm without even removing the carb.

I think money vs. time will probably be your main consideration. I rebuilt my 2 barrel and now the accelerator pump keeps getting clogged with stuff that i probably knocked loose from somewhere else. It also took me awhile to rebuild it because I didn't know how to do it right and had to study the whole thing to figure out exactly how it worked. But because I did rebuild it, I am comfortable with my knowledge of how carbs work. I'll probably never rebuild one again though

A new carb could run up to $220 or more. You can get a rebuilt one from a shop for in between that price and the price of your kit. I don't know how hard it will be to find a rebuilt one though. you'll need to do some shopping to see what you can get for how much. I live in a truck mecca and I couldn't find a professionally rebuilt motorcraft 2 barrel anywhere when I was looking.

If you rebuild yourself, I offer the following suggestions to you:

1) Get ziplock bags to keep all the small pieces in. Put all pieces immediately into the bags. Do not disassemble on carpet or grass.
2) Don't use RTV silicone sealent on the carb
3) Find a gasoline safe nonpermenant sealent and seal everything together with that. I put it on both sides of every gasket, but don't put on enough so that it drips over the sides (I was having vacuume problems after the initial rebuild)
4) Don't tighten everything down as hard as you can. the metal carbs are made out of is soft. If it warps, you could have a gas or vacuum leak. Tightening to "snug" is all you need.
5) Get a can of carb cleaner (it's cheap) and a can of compressed air at a computer store (for cleaning keyboards). You can use it to clean and dry the narrow carb passages. Try not to spray gaskets or other nonmetal parts with the carb cleaner. Cleaner also works handy at finding vacuume leaks after you're testing out the carb, though hopefully you won't have any
6) The gaskets may come apart when being removed. This includes the new gaskets in case you have to re-disassemble the carb, so be careful.

Good luck! (and please forgive my spelling)

 

"3) Find a gasoline safe nonpermenant sealent and seal everything together with that. I put it on both sides of every gasket, but don't put on enough so that it drips over the sides (I was having vacuume problems after the initial rebuild) "


No matter how tempting it is, never use any kind of sealant on a carb or automatic tranny gasket. It's just too much risk of it getting in the the close tolerance and small passages of both.

 

If it was me, I'd listen to franklin over me.

I went sealent happy because I had some vac leaks. I also now have that stuff clogging the accel pump from time to time as I mentioned before...

 

If you have the Holley, it's a good carb. The price for a rebuild kit should be more like $50. I would shop around. Sometime people do a real hachet job on the metering caps and check the base for flush. If both those are ok then I would rebuild. The most important thing that comes in a real Holley rebuild kit is the exploded diagram. Save it.