Flathead Blue Plate Spark Plug Gap?

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kollman32

New member
Using an Autolite 411 on a Blue Flathead. I checked the plug that was in the engine and it was set to 0.025". Not sure if this is correct and I'm trying to make up a cheat sheet. Thanks
 
make sure you index it.. look down in the head with flash light , to where you can see the valves. and mark the head where they are. and set electrode between those marks.. .. just in case you wasent aware.. that's something I had to learn..
 
Thanks for the heads up. The plug is indexed and the open part of the plug is facing directly to the back of the cart(towards carb). I will set the gap, run it and just double check everything looks ok. Thanks!
 
.035 air gap should be plenty. When indexing the plug the electrode tip should be pointed directly to the exhaust port. reason for this is you do no want to shield the spark from the fuel/air coming in through the intake. With it pointed at the exhaust it will contact the spark directly.
 
I used to use facing towards the center of the cyl. and .025" gap was o.k. for 2 cycle outboard racing engines. I also marked on the head with a black perminant marker the area just above the intake valve.
 
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