need help guys , just finished a sig senior enlarged to a 92 inch wing thats painted dress material .... had pland to put a OS 90 FS on it but the plane came in a 14.5 lbs is this enough motor for it ?????

No.

I enlarged a Sig Kadet Senior to 90" wingspan once. I sheeted the leading edges of the wing and loaded it up with a bunch of fuel for a long distance fly. The plane had 54oz of fuel on board and an OS120 Surpass engine. The plane weighed about 14lbs RTF with tanks full of fuel. No lead was used to balance the plane. I had a 14oz tank behind the firewall and a 40oz tank mounted with centerline slightly forward of the CG.

It took every inch of our 450' runway (old field) to just BARELY get into the air. Then it was a VERY scale climb at full throttle at 5 degrees for about 6 or 7 minutes just to get it up to flying altitude. All I could do was cruise around with wings level. No steep turns. It actually felt "scale" to me. It was built for a 100 mile trip. It would do the trip nonstop with a few ounces to spare.

Was it fun to fly? Not really.

Without the fuel, it was about 10.75 pounds. Much more fun to fly.

I know why mine was so heavy. 54oz of fuel for starters. And I sheeted the wing from the leading all the way back to the spar. For the ENTIRE 90" span. [X(]

If I was you, I'd take a look at WHY your plane weighs so much and look for some places to drop weight. Then I'd put a 150-180 4-stroke in it.