1995 9.9 yamaha four stroke

[welshboyjam]

hi first post here ,help
i have a 1995 9.9 four stroke high thrust outboard,
it starts fine and runs fine for aslong as i want it to run 1-2hours, then after running for any time over 10 mins after i stop it it wont start back up again,if i leave it stand for around 30 mins to an hour it will start again and run fine then when i stop it it wont start again ,
any help what anyone thinks this could be ?
i am thinking the cdi unit
my dad thinks the head gasket but the oil is still clean no sign of water in oil or on plugs,
anyone help ,thanks jamie

[99yam40]

Check to see if it is getting good spark when not firing up, that should tell you if the CDI or ignition system has a problem. Then it is a matter of compression, fuel mixture and timing that makes it run