RE: OS 91 FS Surpass problems
Just a thought....
ARE the Bearings freedup on the crank shaft/ and the timming shaft???
If they are then >
Pull the engine, place in on a test stand. Mount the engine with head UP.....I had a magnum .91 that when inverted, had to have the low speed needle to the point of leaning out, or it would build up an foul N'quit....
I am assuming you know how to do the pinch test???? the engine should idle up, when pinched and then quit....
If at idle and you pinch it, and it runs and runs and 10 sec later, it increases rpm's then your LSN is too rich...
If when pinched and it quits almost immediately ... then too lean..
Reset the low idle needle to stock....
start with the Stock High speed needle as well...
And run it in...
If still not running at Low rpm's...... Perhaps it is your Ring/head that is WORN OUT.....
When running RC cars and the engine goes from working good, to NOT idling.... IT IS TIME FOR A REBUILD....
Hope all works out....