Odd metal grinding sound during start
 

I have a model 149 that is making some odd metal on metal grinding sound. Can only hear it during start up while the engine is cranking over. Once it starts the sound appears to stop. It's loud enough that the running engine wouldn't drown it out. Once running and when its shutting down no grinding sound.

It sounds like its coming from the rear of the engine or tunnel cover. No oil leaks, engine doesnt smoke, has power and nothing looks out of place.

Any ideas on what may be causing it.

Sounds like a Starter/Generator issue. There a lot of torque on S/G at start up.

Or the flywheel screen is loose and rubbing on the flywheel shroud.

"It sounds like its coming from the rear of the engine or tunnel cover."

On the tunnel cover, you should see four pan head slotted machine screws. These secure the shroud that covers the fan underneath. They can vibrate out over time as they screw into clips on the shroud. If they are loose or missing, the fan hitting the shroud can make a terrible sound!

No such thing on a 149.

So what will I be looking for in the S/G?

i would say the flywheel screen is loose, or drive hub