85 f150 4x4 lariat (with a duraspark II), and I tried setting the initial timing. after cranking and starter fluid, the engine will eventually kick, but then will (for lack of a better word) "backfire" thru the carb sometimes it's just smoke, twice it's caught the residual starting fluid/gas on fire (small fire, small enough to blow out with your mouth).

What could it be? Is the timing to advanced? carb not sealed to the intake?

btw as stated earlier its a 85 lariat auto with a clifford intake, efi headers, and a autolite 4100 "squarebore". Emissions stuff is still in there at the time but none of the hoses are hooked up. I plan on removing them soon.

Thanks for your help guys

Dan

 

Your timing is either way out of wack or you are way to rich.

 

Are you using a ported/timed vacuum source for the dizzy or manifold vacuum? Whichever one, try the other one.

 

With a 15/16th" socket, turn the vibration dampener to the timing mark at tdc. Check inside the distributor that the rotor is on #1. Take out the #1 plug and put on the plug wire with the plug threads touching a grounded metal. Don't hold the plug!! Turn on the key. Close the dist. cap and loosen the dist. lock down bolt a bit so that you can move it with little effort. Slowly turn the distributor a bit one way, then the opposite, until you see the plug spark. When it sparks, that is tdc. From the point where the plug fired, move the dist. a tiny bit advanced, and it should be good to go. If it doesn't spark, try a better grounded metal part.

The 4100 is a great carb for the 300. I trust you got the 1.08" venturi size? Also, I know from experience that the base of the 4100 is wide for some intakes and difficult to seal up vacuum leaks therefore. Pony Carburetors makes a 1/8" plate to stop that prob. If you got the 1.12" venturi size, it is 600 cfm and could be a bit much for that engine, depending on your build. (To find out, look on the float bowl housing, about an inch above the throttle linkage. There will be a clock face with either 1.08 or 1.12 stamped on it.)

Of course by changing the jet sizes (Holley jets fit), and/or adjusting the float level(s), you may be able to dial it in perfectly. Or it may work like a top the first time around.

I had a 1.08 4100 on my engine. When the secondaries open up it is a whole new world!! Perfect for the high school moments. Good luck.

 

Nothing doing here but the cranking vaccum is about 8-12". What would that have to do with the spark timing? Ported vaccum wont even kick in and your manifold vaccum would barely move the spark if at all.
You add to that every service manual says to set initial timing without the vaccum advance hooked up.....

Not trying to be rude here harte. Just kinda find it far fetched for an engine that wont even start. and backfires.

Also, Dont start your engine on ether please. That is realy nasty stuff and should be saved as an absolute last resort. I may use a case of it in a year but 95% is as a cleaner. I have only used ether in emergencys. My engines all start at -40F temps without it. Please save your engine and use a dribble of gas or some propane.

 

your distributer is 180* out.remove the coil wire. remove the #1 spark plug. have a helper "bump" the key while you hold your thumb on the #1 spark plug hole. when the suden burst of air blows your finger off the hole stop. you are near top dead center. insert a soda straw in the plug hole. do as kevin says with the ratchet on the damper.turn back and forth slowly until the soda straw is at the top of it's travel. look at the rotor. it should be on # 1. if not, pull the dist and re instal. remember to start out before where you want it to be, it turns about 2 teeth when it goes down. if it won't drop in right, you need to tape a deep 15/16 socket on an extention, and turn the oil pump rod a small amount where it goes. to make sure you are in the right spot, mark the side of the dis with a sharpie where # 1 tower is. to set timeing, unhook and block off the vacum advance hose

 

btw, the reason for the fire out of the carb, you are fireing the cyl at the wrong time, prob on intake stroke, and the piston is pushing the spent gasses out of the intake valve instead of the exhaust valve

 

On some engines, like mine, I have to open the throttle plates to get it to idle smooth. With the full manifold vacuum, I don't. I have read where a few others have experienced the same thing. So, it is simple enough to try it both ways. As far as setting initial timing, I prefer using a vacuum gauge. Turn the dizzy until one gets the highest steady reading and then back off 1-2 hg. Drive it and make adjustments as necessary from there.

If one must use ether it is best to only give it a squirt while the engine is cranking...it is nasty stuff.

 

<a href="http://www.flickr.com/photos/46396988@N08/4494844232/" title="DSC_0352 by reuter562, on Flickr"><img src="http://farm3.static.flickr.com/2714/4494844232_e8a856209e.jpg" width="332" height="500" alt="DSC_0352" /></a>

Found the problem, washer got behind the #5 intake runner. Major intake leak alittle fire and a burnt gasket. I thought I miss placed the washer. :facepalm: Guess the truck wont get another shot till next week. I have never felt more mech. challenged than when working on this truck. Modern Bmw engines no problem tore em apart plenty of times. Both inline six's but totally different. lesson to all "Pay Attention"

btw slighty used/cracked ancient clifford intake for sale cheap

 

oh man, you have luck like me.. I would take that to a good welding shop, and have it fixed. then take to a machine shop and have it planed flat again, will be much cheaper than buying a new one

 

I'm sorry to hear it, but at least you found the problem. I would weld it too, as Dusty said. If there is a flange thickness difference, you can go several routes. I just took the oe washers and ground down one side. I've also seen guys take two hardened washers of different sizes, the larger one goes on the bolt secondly, so that it can be moved about to compensate where one flange is thicker.

Good luck.