motorbikemike45
Member
I'm glad you found the problem and there wasn't extensive damage. Don't feel bad about not noticing the lack of compression. These engines have a compression release, so it wouldn't be obvious. Back on the road now!
From looking at the manual it seems to be the smaller o-ring from the 'check valve plate'
The o ring was still intact with a couple of marks where the valve had closed on it.
The larger o-ring was still in position.
No I hadn't done anything to the engine prior to the problem.
Happy Valley, both of those rings were and are still in place. As you say the smaller one is fitted around the carb mounting bolt.
The subaru manual shows a small o ring behind the 'check valve plate'
I've e-mailed them to ask what the check valve is for - do you know?
Sorry I've not had time yet to see if this o ring is still present.