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Bronco runs well for thirty minutes. Then won't turnover after stopped for 10 minute

gladkin

Jr. Member
Joined
Aug 8, 2009
Messages
78
Okay,

I have a question on my Bronco 302 V8. I will run the vehicle for 30 minutes or so and it runs totally fine. I am running at temp of 190 and everything is running great. Once I stop and turn off the engine for a couple minutes, and get back in, I will try to start and it has a real hard time starting. The motor cranks really slow (almost like a slow 'chugging') and does not want to turn over. I can get it to turn over but have to push the gas pedal a lot. Then a big plume of smoke comes out the back (I think from being flooded for some reason) and I can get it to run correctly again. (I don't want to push the gas when starting, but it is the only way I can get it to turn over once it has been warmed up for 30 min or so.) It always starts great when cold, the problem is only when it has ran for a while.

Is there something wrong with the carb that I can fix? I believe that's where my problem is coming from.

Any suggestions would be great.

Thanks all!

Michael.
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
Fuel is boiling in the carb and flooding the engine when it heat soaks. Lower the float level and/or insulate the carb from manifold heat.
 

fungus

Bronco Guru
Joined
May 27, 2009
Messages
1,548
Loc.
Kaneohe Bay, Oahu
If it were carb related wouldn't it still crank over at normal speed and just have a hard time getting fuel? Sounds like a battery is going bad to me. Bad cables? I'd load check the batt and clean all terminals and cables and check grounds. I've had rigs do the same thing and each time it was a batt going south. Starts fine when cold but when the engine bay gets hot the batt just won't cut it after a short shutdown.

With the very slow cranking and you pushing the gas pedal you are flooding it. When it finally catches, black smoke... PS, pushing in the gas pedal won't make the engine crank over better but seems to be a natural reaction when she's having a hard time starting.
 

wtkeller1

Newbie
Joined
Feb 27, 2010
Messages
46
Had the same problem with my 302 and I ran a ground from battery to the starter bolt, problem solved.
 

Pa PITT

Contributor
Bronco Guru
Joined
Jul 15, 2005
Messages
11,252
Loc.
Stephenville TEXAS
Extra good grounds is always my answer.. I like and extra from one of the starter bolts up to about the same place as a 2nd from the battery neg. to some place on the frame.. I'll usually put one off the alt bracket to the frame also. I guess I try an run 3 extras.
 

av bronco

Bronco Guru
Joined
Mar 3, 2008
Messages
1,742
Loc.
Palmdale CA
Timing too far advanced and/or batt/starter/wiring. first Id check the timing tho. Also when you pump the gas on starting hot you are squirting gas into the engine flooding it making the black smoke.
 

jdowns67

Contributor
Owner since 2001
Joined
Feb 27, 2010
Messages
37
Loc.
Wilmington, NC
I had the same problem a couple of weeks ago. My bet is that you just need a new starter. When they start getting hot they loose power until they cool off again. They get the hottest after you are running a while then shut it of since it doesn't have the air going by it while running. If you have headers, it's even worse. I put a new one on mine and I could tell a difference immediately. It spins faster even when cool.

JD
 

dbevans2249

Sr. Member
Joined
Sep 21, 2003
Messages
610
Loc.
Buena Park, Ca.
Check and clean the Battery Cables. Make sure they are not cheap ones that dont realy have any wire in them. Make sure the starter to bellhousing is clean and the bolts are tight so it will groung well. Then do a starter motor amperage draw test with an inductive amp meter. Then you will know if the starter is going away.
 

75bronco08

Full Member
Joined
Apr 16, 2008
Messages
234
Loc.
sublimity,oregon
iv had that same problem as others have said replace start and check cable or just replace it from solnoid to starter while doing the starter.
 

mlaird

Sr. Member
Joined
Jun 16, 2009
Messages
428
Loc.
Houston,TX
had the same problem and it was the original starter. it even tested fine at the auto parts store, but after a drive id shut it off and then try and turn it on again and get a really slow cranking sound which would turn over sometimes and not turn over others. the high torque mini starter was all i needed to fix it
 
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