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Weak spark at plugs

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Ricky238fourwinns

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Engine was running poorly. Shaking and dumping gas out the exhaust. Spray pattern was wide and thick on the TBI. Replaced injectors,fuel filter and MAP sensor. Started up and ran smooth with a high idle(1200rpm) and settled down to 900rpm. Ran for about a minute and then stalled. This happened three times, I replaced spark plugs and now it won’t start. The spark at the plugs seams weak even with original plugs, spark at coil is much stronger. Also replaced cap and router any ideas would be appreciated
its a 1999 5.7L Volvo Penta w/TBI
 
Last edited:
Ricky238fourwinns said:
Engine was running poorly. Shaking and dumping gas out the exhaust. Spray pattern was wide and thick on the TBI. Replaced injectors,fuel filter and MAP sensor. Started up and ran smooth with a high idle(1200rpm) and settled down to 900rpm. Ran for about a minute and then stalled. This happened three times, I replaced spark plugs and now it won’t start. The spark at the plugs seams weak even with original plugs, spark at coil is much stronger. Also replaced cap and router any ideas would be appreciated
its a 1999 5.7L Volvo Penta w/TBI
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Does anyone have any input on my problem?
 
Are you checking spark with a spark gap tester? Does the coil get hot when running? If you dont know the age of the plug wires replace them. Check for spark out of the coil with a open air spark gap tester it should jump A 5/8 gap with a brte blue snap. Once you get it running check the coil if it is getting hot put a ballast resistor to coil pos and go boating.
 
kimcrwbr1 said:
Are you checking spark with a spark gap tester? Does the coil get hot when running? If you dont know the age of the plug wires replace them. Check for spark out of the coil with a open air spark gap tester it should jump A 5/8 gap with a brte blue snap. Once you get it running check the coil if it is getting hot put a ballast resistor to coil pos and go boating.
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I appreciate the response back, I checked the cap and rotor again and found a hair line crack in the rotor and and small burn mark spark was going to ground, I’ll never use west marine products again, off to get Volvo Penta parts. Will do a follow up to this post
 
Ricky238fourwinns said:
I appreciate the response back, I checked the cap and rotor again and found a hair line crack in the rotor and and small burn mark spark was going to ground, I’ll never use west marine products again, off to get Volvo Penta parts. Will do a follow up to this post
Click to expand...

West Marine does not make these parts... Likely from Sierra a major aftermarket seller of parts for marine use. Return defective cap to West Marine for a refund if less than 30s days old. BTW...Volvo Penta does not make disti caps, just rebrand parts from someone else.
 
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