Motor boggs down under rpm?
10-01-2003, 01:56 PM
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Motor boggs down under rpm?
I have a 351M in my 85 bronco. At idle the motors fine plenty of throddle response. When I am driving along and step on it it bogs down to the point of sounding like it is drownding I have a holley 600 on it and have tried everything timing and carb adjustment am I not adjusting the carb right. When i let off the gas and go back to half throddle the motor runs fine..
10-01-2003, 02:06 PM
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An '85 Bronco wouldn't have a 351M in it stock, it would have a 351W. Has the motor been replaced?
10-01-2003, 02:10 PM
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I'd start by making sure the accel pump is working. Also may want to look at any rubber fuel lines. They may be getting soft and collapsing.
10-01-2003, 02:43 PM
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It has been replaced with a 351m
10-01-2003, 02:55 PM
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It sounds like you may have a vacuum advance problem. Test the diaphragm to see if it will hold vacuum. If it doesn't it will need to be replaced.
10-01-2003, 03:09 PM
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Thanks I didnt even think about that...
Ross
10-02-2003, 05:22 AM
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Check or change the fuel filter(s). Could be plugged just enough that at a light engine load enough fuel gets through to keep running but when you get after it, it runs out of gas. When you back off of the throttle, the flow catches up and starts running again.
10-02-2003, 03:05 PM
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I Checked the vaccum advanced and it was fine I recently changed the fuel filter and still have the problem ...... help
10-02-2003, 03:07 PM
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How are the rubber lines? They get soft and collapse internally.
10-02-2003, 03:43 PM
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Could also be the fuel pump failing. Since you have a Holley 600 on it, I'd assume you are running a mechanical pump.
10-02-2003, 06:24 PM
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OK it's tough to diagnose without actually seeing it but here's a couple more things to look at. Does it still have cat. conv. on it? I've seen plugged cats cause this problem.
Have you checked the float level? If it's too low it could be sucking the bowls dry which would cause it to starve for fuel.
Last edited by Bill_Beyer; 10-02-2003 at 06:27 PM.
10-04-2003, 10:07 AM
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Thats the last thing I am check is the floats I hope thats the problem...
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