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Author Topic:   missing and running hot
AC156
Dirt Freak

Total posts: 295
posted July 06, 2002 08:37 PM
after i run about 3 or 4 laps the car starts missing at the end of the straights and when i go into the turns. Also it starts getting very hot. I checked the float in the carb and it is set right. any ideas??

[This message has been edited by AC156 (edited July 17, 2002).]

BayouGent
Dirt Forum Racer

Total posts: 87
posted July 07, 2002 11:00 PM
Here are a few thoughts...

Are you running foam in the fuel cell? Could there be a possibility that the hose that runs down into the fuel cell has curled up towards the drivers side and is not picking up fuel properly when you go into a turn?

Fuel filter could also be partially plugged. When running in a straight line fuel is level in float bowl but if not enough fuel is getting into carb then when you go into a turn the fuel goes to one side of the bowl and engine can't get enough, starves for fuel, which leans out engine and causes temp to rise.

The fuel pump might be getting a little weak which could also cause the conditions described above. I've seen a weak fuel pump make an engine sound like it needed bigger jets, but all the jetting in the world can't correct the loss of fuel pressure.

That's all I can think of at the moment. Hope this helps you out. I'll post any other theories I have if they come to mind. Good luck!!

AC156
Dirt Freak

Total posts: 295
posted July 08, 2002 04:13 PM
thanks, i will check all of that. any other ideas?

BayouGent
Dirt Forum Racer

Total posts: 87
posted July 09, 2002 04:01 AM
Just out of curiosity what type and size carb are you running?

AC156
Dirt Freak

Total posts: 295
posted July 09, 2002 11:01 AM
carb is a holley 4412 500 cfm 2 barrel.
I checked the fuel filter and there was some trash in it. hopefully that was the problem.

[This message has been edited by AC156 (edited July 09, 2002).]

AC156
Dirt Freak

Total posts: 295
posted July 13, 2002 09:38 AM
i ran this friday night and it is still missing. it did not get hot this time though. it does it at the end of the straights and almost all the way through the turns. it seems like it does it worse when the track is tacky (during the heat race). the track dried out some for the feature and it didnt do it as bad. any other ideas??

GTH RACING
Dirt Roller

Total posts: 11
posted July 15, 2002 03:00 PM
what size jets are in your carb it sounds like it may be a couple of sizes off

BayouGent
Dirt Forum Racer

Total posts: 87
posted July 16, 2002 12:56 AM
OK with the problem occuring at the end of the straights too it's starting to sound like a jetting problem. What do your plugs look like? Do the tips of the electrodes look white, tan, or black? I've also seen a car act similar to this with a BENT float. Setting could seem ok but if it's bent it could be hanging up in certain situations. If the float is plastic the bent float theory is blown away but I've also seen a plastic float get an indention worn into it where the float tab contacts the needle valve. This can cause the float to not operate smoothly and maybe even hang up. Just a few more things to check AC. If those plugs are white on the tips go up at least 2 jet sizes. If it ends up a little fat you can always drop down to the middle. I hope this helps you!! Good luck!!

AC156
Dirt Freak

Total posts: 295
posted July 16, 2002 08:52 AM
thanks guys. we run 77 jets. I think i may have found something. the #6 and #8 spark plug wires were burned pretty bad where they go onto the plugs. i think that they may have been arcing at high rpm and under load. what do you guys think? we canged the wires. we will try it friday and if that doesn't fix it, then we will see about the carb. thanks.

racer17j
Dirt Forum Champ
Total posts: 1565
posted July 16, 2002 10:18 PM UIN: 54865418
you might have found it there i had two wire touching last week and i noticed i did run a little hotter than usual one other thing does it do it when you are heading straight or when you set it for the turns mine did that a couple weeks ago would die when the car rolled into the turn it was a pinched fuel line

AC156
Dirt Freak

Total posts: 295
posted July 17, 2002 01:48 PM
it starts while i am still on the straight. we checked the line and changed the fuel filter. everything was ok there.

86robertsracingcms
Dirt Newbie

Total posts: 3
posted July 18, 2002 12:23 PM
We had the same problem, but you must verify if it is a fuel delivery problem, or a ignition problem. Change wires, plugs, and your cap. This helped us. Good Luck

------------------
God Speed
->Ronnie

BK19
Dirt Freak

Total posts: 285
posted July 18, 2002 08:44 PM UIN: 40696038
how big of spark plug gap do you have? if the gap is to big the engine will miss at the end of the straights

killermiller
Dirt Roller

Total posts: 24
posted July 18, 2002 10:53 PM
I had the same problem. Couple of plug wire boots melted. My problem was my cam lost two lobes and wasnt letting the exhaust out! I got lucky and had a cam ordered allready before I found it out! The new cam cured my problem and luckly didnt cause any major damage.

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