Reply To: bottom cylinder fouling Big Twin 25hp

[The red boat]

I can’t believe my last post on this subject was back in November! I finally put the motor in a tank this weekend – FINALLY

It took a while to start but when it did, it only ran on the top cylinder. Ran well in fact but no fire on the bottom cylinder.
After the spark test in my previous post this was surprising.

What I discovered was that the Atom module for the bottom cylinder was not working consistently. Maybe my wiring wasn’t secure or it was somehow grounding out but I could not get it to fire consistently.
I swapped out another Atom in its place and the motor fired off an idled perfectly in the tank for as long as I wanted it to.

I let it warm up so I could make another pass and do a final torqueing of the head bolts .
so, for now, all is well. Looking to get on the lake in a couple of weeks to fine-tune my carb needle adjustment.

thanks for all the replies and advice as always.