backfires and stops

[BurleyCove]

Changed the plugs, dist caps and rotors on both motors. started them up after each step and checked that the motors were running fine. They purred like kittens even up to 3000 RPM, As I was just letting both idle for a few minutes before cleaning up, the starboard motor backfired and stopped. I checked for any crossed spark plug wires but it looks fine. Took the new dist cap off and looked for cracks but it looks good. Started it again and it idles perfectly smooth for a few seconds then backfires and stops, Also, the fuel pump is much louder than the port motor. Its probably something I did but cant find it right now.


Any ideas on what to check would be appreciated.

Thanks
Bill

 

[dwna1a]

Did you change the pickups inside the distributer? Also does your boat have a Thunderbolt Ignition System?

 

[northshore]

Is she fresh out of storage? Was the fuel treated before she got stored?
Possible phase separation issue if the fuel had any ethanol....

 

[BurleyCove]

Yes its a Thunderbolt ignition. I treated the fuel before storage both motors use the same tank so I dont think its the fuel. Did not change the pick ups. I think i'm going to put the old dist cap and rotor on tomorrow am and see if that helps.

 

[CliffA]

wouldn't hurt to check the ignition timing.....

cliff

 

[dwna1a]

I'm with Cliff, but go the easy less expensive path first. Change the cap and rotor back to the ones you removed first. If it's still doing it then the Thunderbolt may have gone. The backfire leads me to a timing issue, which is what the Tunderbolt controls. Good luck, keep us informed

 

[BurleyCove]

Ok Time to fess up when I triple checked the spark plug wires number 1 and 3 were crossed. Once they were in the right order the motor ran fine --- for about 3 minutes. Then it sputtered and died. While trying to re start the batteries would not hold a charge. Sooooo 2 new batteries (a starting battery and a house battery) , a new fuel pump, and a new distributor sensor later the motor is purring like a kitten. probable did not need the sensor but it seemed like a good idea. Now here's the fun part. While I was putting in the new dist sensor, my battery charger goes " zzzzfffffftttt" and smoke comes out the top. even though I admit to not being the best mechanic around I'm pretty sure that is not considered acceptable behavior from a battery charger . sooo i'm in the market for a new battery charger. any suggestions?

The other lesson I learned from this (besides triple checking the spark plug wires) is that I can do one armed hand stands in the ER while looking for a dropped tool.

 

[dvx216]

When metal tools take a trip under the motor a magnet on a flexible wand really comes in handy or you can do what we do when working on large oil filled transformers tie strings to your tools. But doing one handed head stands will give you one really buff arm.