One of my buddy's here on the forum has a problem I was hoping some of you motorheads could help with. Couple yrs ago he didn't get the boat winterized in time and the utah cold cracked the block on a stock merc 350. I'm not sure exactly which 350 it had in it but it was trashed so he decided to get it replaced. After weighing over his options he decided to spend more money and have a 383 stroker built for it. The marine dealer contracted the job through a reputable marine engine builder here in utah. Now the problem is this. With the stock set-up he was running before he was getting between 55 and 60 mph @ about 4800 to 5000 rpm. The stock engine was rated at about 260hp. He was told this stroker would produce around 400 hp. So we took it out recently and the thing is a pig. The best it will do is 47 mph @ about 3800 rpm. We ran the stock 21 pitch prop as well as a 22 and it didn't seem to make much difference. Now he seems to be getting a bit of a run around. We are being told that the ecu may need to be reprogrammed and that the engine is not getting the right air fuel mix. I'm thinking that someone screwed up. This engine runs great. It purrs all the way throught the powerband, and has no hiccups or hesitation. But it runs more like a stock 305 instead of a 350 or 383. We are testing it at an altitude of about 2300 ft.
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