I just got my 35 MB back together. Put on the MIkuni carb bps cross over exhaust and bps cam into it. I got the cam broke in and reassembled the rest of the out drive and ran the motor a bit and set my pilot air screw. Then I went to test the rev limiter (4600 rpm limiter) at 4500 rpm the engine started back firing out the exhuast really bad. wondering if my main jet may be too big? any other ideas?

when your running the motor especially outta the water their is a delay in what your tiny tac says and what your engine rpms really are. so even though it might only flash 4500 on the tac the motor is probally at 4600 or more. Its hard on the engine to keep hitting the rev limiter if it does it under a load in the water u may need to change your gear ratio

Talked with BoatDr and he said the same. Gonna take it out on the water tonight and give it a whirl. Thanks to everyone for the replies. I love the sound of this new exhaust. Hope it runs as good as it sounds.