problem with a Blake max no vac to bottom 2 cylinders

Love to read the forum. I took my boat out and I have a 87 150hp Blake max. The motor has just been rebuilt by a boat mechanic. First time out. It started but shakes a little. Every time I give it the throttle it dies. I took it home. Compression test is 130 on all cylinders. Good spark to all cylinders. Squirted gas in cylinders through carbs and all changed motor but the bottom 2 cylinders. Pulled plugs and squirted fuel in holes in bottom 2 cylinders and they fired. Plunged off each carb and it changed motor. But the bottom carb did not Chang the motor. No vaculm to bottom carb. What is going on? Problem with reeds or a seal of some sort? I have never been inside an outboard before.

Take the motor back to the rebuilder !!!

What are you using to measure intake vacuum?

I put a rag up to the carbs. It sucks rag in on the top 2 carbs. Not at all on bottom one. I pulled all plug wires but bottom 2. Turned it over. Squirt fuel in carb. It would not run. I pulled the 2 plugs. Squirted fuel in the plug holes and it would run a couple reves.