F225 goes very high rpm on startup

[Kallllll]

My outboard f225 4stroke 2007 running 1200 hrs now and never had a problem
Last trip the rpm went high to maximum rpm at idle that I had to shut it down

I tried to start the engine today .. Same thing happened .. It goes crazy high rpm right after it starts .. With loud back fire


What is wrong?

[99yam40]

have you even looked for any problems before asking us who cannot see your motor or controls?

[Kallllll]

I took a look on the cables inside the engine but did not notice anything

[greasyshaft]

[garylowe]

i had the same issue. it had a crack in the intake manifold its plastic.you can test it by starting the engine and spraying carb cleaner and the RPM will lower. i took mine off and cleaned it up and put some 5200 on it and been runing for years .