Evinrude 25 Trouble

Hey all, new to the forum and have been browsing with no specific luck. 1980ish Evinrude 25 that engages forward, neutral, reverse successfully (although it does seem a little sloppy and not a solid/firm shift). My problem: The engine revs easily at high RPMs in neutral, but once in forward, the engine is bogged as though it has a severe load. Every now and then, it is as though a switch is flipped and the RPMs shoot through the roof and the boat (14ft jon boat) rockets forward for a split second before seemingly slipping out of gear and bogging back down. Once back at a low idle, I can switch to neutral and finally reverse where I have 100% power the entire time. This test was done several times to eliminate any variables with the exact same outcome. What are your opinions?

Re: Evinrude 25 Trouble

Pull one spark plug wire at a time when the prob occurs and see if it's firing on both cyls.

Re: Evinrude 25 Trouble

So I pulled the spark plug wires. The bottom one only works sometimes. Noticed a crack in the lower coil... Im thinking that has a part in it. I might have thrown the timing off too while turning the flywheel by hand (not entirely sure if this actually knocked the timing off but it wont start at all now). How do I get it back in proper timing? Wont start now and just backfires out of the exhaust.