Thread: Need some timing advice

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OK, let me see if i can explain what is going on......
I just had my ford 460 rebuilt for my jet boat. Put the motor back in the boat and no i am having problems with it starting and the back firing

It first back fired out of the headers and the carbs.. i mean loud as hell enough to give ya a heart attack... so i advanved the dist. clockwise and now it just back fires out of the carbs ( gas and flames). It does start but only for a second and then boom out of the carbs it goes. I have tried advancing the dist. more clock wise but that doesnt seem to fix it.. any suggestions or should i keep turning the distributor...


as you can see i know enough about timing to get in trouble.

thanks in advance for you help

Originally posted by DennyW
If it's back firing and flames out the carb, you have it to far advanced.

OK, how do i fix this. I really do not know alot about distributors and how to time it well .. can you elaborate on what you may think i need to do.. should i turn it counter clock wise

sorry for my ignorance

sounds like you might have some wires crossed also, you need to go back and check that to,

Thanks for the great replies.. ok what i did was turned it back the other way and it started back firing out of the headers again. so i started back clock wise again and just keept going until the back fires out of both the carbs and headers has stopped and it runs but now it idles way to fast ( 1500- 2000 rpms )but if i try to turn it back to slow it down it back fires out of the carbs... any suggestions??

thanks so much for all of your help

Originally posted by DennyW
If it's just rebuilt, you want to run it at 1500-2000 to break in the cam, and related parts. Do this, while watching the water temp, and oil pressure for about 20 minutes. Once done, the choke should be wide open, and tape the throttle easy, and it should come down on low idle. If not, you have to turn the carb base idle throttle screw to lower the idle speed.

thanks for your help.. i will put her in the water tomorrow to see how it works. THe auto choke is disconected so it doesnt choke.

It has 2 holy 4 barrels on it so i guess i need to adjust the idle screw on both of them.. can you tell me the best way to adjust the idle with the carbs

so your saying it is ok to run it around 1500- 2000 like that for about 2o min then adjust the idle....

about the timing.. how do i go about fine tunning the timing??

thanks for your help this board is great

if you got fire, poping or spitting out of anything then you either got the valves opening or the dist. firing at the wromg time. assuming your cam is timed right, your valves adj. properly then the only thing left is the fire. it has to be out of timing or the wires crossed, and iff you can move the dist and move the miss fire then ib say you have it in time, so that leaves the crossed wires. 15426378 rotor ccw, 1234 right side 5678 left side.

i just saw where you said you could make it stop poping that good, but you need to set the idle with the idle screws not the dist, you need to set the timing with a light and leave that alone.

Originally posted by lt1s10
i just saw where you said you could make it stop poping that good, but you need to set the idle with the idle screws not the dist, you need to set the timing with a light and leave that alone.

Can you point me to a good site for timing the engine with the timing light or if you have some pointers i would like to hear them

thanks again for your help

im not sure on the boat so im not the one to tell you what the advanced timing should be and when it should come in im sure its dif for a boat. somebody on here must know though,

ok well it starts good now but i dont know a good way to adjust the idle speed still idles way to fast. I turned the carb idle screws clock wise but that seemd to make it go faster.. am i doing this right. .. can anyone help me out with this. I engine has have 2 holley carbs on the motor so any ideas of how to go about doing it. I have to adjust them both.

Do you turn the screws all the way in and then back them out??

any help is appreciated
thanks

Originally posted by DennyW
Why don't you take a picture of it, and post it. It's hard to see what's going on when you can't, and don't know what you have.

great idea.. i will do that and post it.. man i am so close ..

ok well i am about to post the pics.. chaging up the camera now.. but here is an update. I have turned out both idle screws primary and scondary and i have also turned in the air mixture screws all the way in and backed them out 1.5 turns. and the motor still idles around 3000.

float level has been checked and no vacum leaks as all the vacum lines are plugged with new stoppers.PCV valve hose is intact with no cracks. ( can a bad PCV valve cause this??? just a thought)



side note: choke lever is disconnected on the carb so the choke does not work.

well let me see if my camera is charged...
thanks


let me know what you all think

Originally posted by DennyW
I fixed up your buddies picture a little.

lol... thanks so much i needed a good laugh after this head bang ordeal.. i am getting so frustrated i dont want to ruin this new engine..


http://www.clubhotrod.com/photopost/...php?photo=6458

http://www.clubhotrod.com/photopost/...php?photo=6457
http://www.clubhotrod.com/photopost/...php?photo=6456
let me know what you think

thanks again denny


here is an update. I have turned out both idle screws primary and scondary and i have also turned in the air mixture screws all the way in and backed them out 1.5 turns. and the motor still idles around 3000.

float level has been checked and no vacum leaks as all the vacum lines are plugged with new stoppers.PCV valve hose is intact with no cracks. ( can a bad PCV valve cause this??? just a thought)



side note: choke lever is disconnected on the carb so the choke does not work.

Originally posted by DennyW
Oh, and a little info on the carbs. Do these have the anti-blow backs installed to protect the power valve from back fires ? Carb number from the air horn would also help.

http://www.clubhotrod.com/photopost/...=12981&thumb=1

pics of the carb linkage.. of both of them.

about the blow back i am not for sure about that. Are you thinking the power valve may be damaged from the back fires?? if there is a way to tell if you have the blow back devise let me know

here are the numbers from the air horn on the carbs... both carbs have the same numbers.. 1850-5 1940 ( this number is under the 1850-5)

Denny thanks for all your help
let me know

Originally posted by DennyW
I'm working on the other info. What I saw, or seems to be off is, I see you have manual chokes. It looks like from the picture that on the secondary carb, the choke arm appears to be on some. What you want to do for plain old mechanical checks is this. This is all done without the engine running.
Take off the air stacks
Unhook the linkage going from the front carb to the back carb while paying attention to see if the throttle moves on either carb. (rod length could be off)
Next, take off the linkage on the secondary carb that goes to the throttle inside. Also while watching to see if the throttle moves closed.
One carb at a time, turn the idle screw counter clockwise until lose. If you move the throttle you should be able to detect a slight stickyness because the throttle plates should close all the way. If so, thats good. Now turn the screw clockwise, just until you no longer feel the throttle plates sticking. Do that on both carbs.
You also want to make a visual check to make sure the secondary throttle plates are closed. If the vacuum diaphram linkage is sticking, this could be holding the secondary throttle plates open enough to up the idle. (the adjustment for the base idle is on the underside). (pictures will be coming on this)
Float levels, with the side sight screws out, not running right at this point, the fuel should be right at the bottom of the threads, or slightly lower because the engine is cool. If you shake the boat, the fuel should just wet the threads.
Air adjustment, turn clockwise, and lightly seat them, turn counter clockwise, 1 turn, both carbs, all idle air mix screws. By this time, you should have found something wrong.
When you go to put the linkage back in for the front to back carbs, it should fit without moving the throttle lever. (O fit).
Now, check the throttle linkage from the inside to the secondary carb, that should also fit with a O fit. Without moving anything. Let me know from this point.

Thanks for the great post.. here is what i have done..

1:undid the thottle linakge that concts both carbs together.. zero movement the throttle plates didnt move and are closed . So i think rod linkage is proper length

2: idle screws: ok i already had those back out as far as they can go ( counter clock wise) they are not touching anything... so again the main throttle plates are closed ...

3: idle air screws.. Had them at 1.5 turns out but i will do the 1 turn out.

4: float level.. is good.. fuel just dribbles out

5:OK to the secondary throttle plates: ( which i think is the problem). they are slightly open. i can close them by hand but they spring back open. I backed out the screw from the under side but it wasnt touching the plates even befor i backed them out ( is it a slotten screw ) to adjust them but they still remain slghtly open. .

It seems as though as something is keeping the secondary throttle plates in the slightly open postition.. I think that is what is causing the fast idle. ..

again you are a great help and i am learing a ton from this.. let me know waht you think

Chris



EDIT:: here take a look at this any maybe it will clear it up for you on the secondaries throttel plates
http://www.clubhotrod.com/photopost/...php?photo=6468