We had a puzzle at the field today. A member put a new set of wings on a Harrier 90. The previous wings were destroyed in a rendevous with the outhouse.
Two flights of about 2 minutes and dead stick. The engine was a Saito 1.00. The engine ran well for 2 minutes. Glow plug was changed after the first deadstick re-fuel and started up.
To quote one of our twisted mentors, the only thing that will stop a four stroke is no fuel. So, I told him the engine was out of fuel. He took the canopy off and the tank was practically full. I told him that the clunk fell off or the clunk line came off or something like that.
He removed the tank. He then told me, "Hey, there are two clunks in here!"
It had three lines and the fill/drain line had a clunk. I held the tank up the the light and one clunk was stuck in the upper right corner of the tank. That was the main fuel line clunk.
I just gave the tank a swing and the clunk came down. We figured that the clunk line was thrown to the front of the tank in the previous crash. When the tank was full, it ran fine and after about two minutes the level was low enough that it was not feeding fuel.
Tank went back in and all was fine.
Anyway, the only thing that stopped that four stroke was running out of fuel.