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| 350 5.7 New Motor Backfires under qui... |
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Heather
New member
Username: bonton
Post Number: 1
Registered: 08-2009
| | Posted on Thursday, August 27, 2009 - 06:17 pm: | 
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New motor, have tried everything, even a new holley carb. Idels great but when you get in it to pull skier (quick accleration) it backfires. New Tach, corrected timming. Any ideas are welcome! |
makomark
Senior Member
Username: makomark
Post Number: 1324
Registered: 09-2008
| | Posted on Friday, August 28, 2009 - 12:03 am: |
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backfires...out the carb?
Does it rev up after the backfire, or does the backfire continue?
New boat or repower?
Which distributor is on it....any ECU? |
Heather
New member
Username: bonton
Post Number: 2
Registered: 08-2009
| | Posted on Friday, August 28, 2009 - 09:10 am: |
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Yes it backfires thru the carb, and it does rev up after the backfire. Repower, it's a thunderbolt HEI. |
makomark
Senior Member
Username: makomark
Post Number: 1327
Registered: 09-2008
| | Posted on Friday, August 28, 2009 - 12:51 pm: |
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Best guess is inadequate accelerator pump shot. They are usually caused by a lean condition during transistion.
Which thunderbolt - 4 or 5?
ECU - y or n?
Check the carb's installed angle, the float settings, and fuel pressure delivered at the carb.
Did you verify the timing advance function? |
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