Almost new RobinSubaru EH035 suddenly stopped and will not restart.

[motorbikemike45]

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!

 

[darwin]

Need to find where that oring came from, carb might be sucking air where it shouldn't and effect the performance.....glad you found it.

 

[HeadSmess]

i said to check the valves, didnt i?

fixeded! excellent.

 

[Happy Valley]

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.

On the left is the large ring that seals the air assembly to the carb, on the right the smaller ring that acts as a cushion for smooth movement of the choke behind the plate. Curious that it was still intact because it fits around one of the carb mounting bolts.

 

[Oban]

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.

 

[Happy Valley]

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.

That 'check valve' is part of the emissions control system feeding unburnt gases back through the air cleaner assembly.

#884 is the 'plate' and 895 is the o-ring that fits inside it.


The white disc is the 'plate' and the is o-ring next to it.

It's strange it would or even could get sucked into the intake because that o-ring is buried behind that whole little emissions assembly, is on the outside of the filter element, and it's larger than the hole in the black air cleaner assembly into the carb.

 

[Oban]

If it's any help, I kept the o-ring and it is 13.5mm external diameter.
It's a mystery and interestingly the e-mails from Subaru have stopped once I asked where the o-ring came from!
Thanks for your interesting posts