Plugs

[sadams714441]

What is a good plug to use with a Brodak 40 and LA 40

[Bill Little]

Any good "hot" plug. 

Thunderbolt is the choice around here for many. 

"Hot", R/C, or 4 cycle plugs.

[sadams714441]

Thanks Bill I'll check hobby store today.  Getting ready to break both engines in.

[Bill Little]

Thanks Bill I'll check hobby store today.  Getting ready to break both engines in.

Just be sure to replace the plugs AFTER you get them broken in.  I have been told by a few engine builders in the past to do so, and I have found out first hand that they were correct.   I have seen a few engines go sour at just the wrong time if the break in  plugs were not replaced. 

I have a few plugs that I use just for break in, then put a new plug in for the first flight.  If the plug goes sour on the "ground", no problem.  Cheap insurance.

[john e. holliday]

Why is that?  I just had a plug die on me sometime between the 10th and 11th flight.  I had to replace the plug on the RO-Jett before I could make 11th flight.  I use Fox idle bar plugs.  DOC Holliday

[Russell Shaffer]

I am guessing, but there could be some metal particles floating around the combustion area during the break in period?

[RandySmith]

Yes Right your  are  Russell

Also the plug sometimes takes a beating in breakin.
I have seen the elements kncked sideways  in engines  many times  during the  breakin

Randy

[Bill Little]

AFAIK,  it is from what Russell says.  Gunk from breakin prematurely fouling the plugs.  I hope Randy Smith chimes in on this one.  I just do what I'm told most of the time.   
I'm good at learning and remembering.  I don't theorise, or investigate!  The really smart guys do all that for me. 

EDIT:  Well, as I was typing, Randy DID chime in!