backfire on startup? what causes

[peacekeeper6]

well i finnally got my boat running.. . i think. i started it the other day and it started but reved to near 3k then like reved up a bit started dieing revved again then backfired and died. broke the woodruff key and i got anew one but it wont start. the battery seemed really weak so i am tackling that first. my question is what could of caused it to backfire and do that when i started it?

 

[eurolarva]

Re: backfire on startup? what causes

Has the flywheel been removed before this happened? If it was not torqued down tight enough it may have busted the key.

 

[peacekeeper6]

Re: backfire on startup? what causes

yes but i torqued it down tight, i know it backfired so i am sure this is what broke it.