We have a 1991 4.3l Mercruiser and just replaced the engine on it with a brand new engine. We got everything hooked up and had a boat guy check everything over and align the drive with the engine. He had it running fine at his place with the muffs and when we took it out the first day for a couple hours it ran fine. We kept it under 3500 rpms all day long and varied just like the manual said for break in period. Took it out the next day and got out about 5 minutes after letting it warm up for a couple minutes and while running at about 2500 rpm it all of a sudden started dieing on us. It acted like it was starving for fuel. It would start to stall then rev back up. It runs fine at anything under 1000rpm. We checked the fuel pump, it pumped about a half of a coffee cans worth of fuel in roughly 20 seconds so it is getting plenty of fuel. Also double checked by running the boat on muffs and every time it started to stall sprayed a little carb cleaner in it and it still stalled. if it was fuel pump issue that should have brought it back to life. We adjusted the mixtures a little but not all that much since the boat guy said he adjusted those but he did it with muffs on and not under any load. We then tried it again today with muffs on and using the throttle only just revving it up a little. Every time we got above 1000rpm it would stall out again unless we brought it back down below 1000rpm. We are trying to not spend a whole lot of (more) money on fixing it but are about ready to take it to a marina and just tell them to fix it. Any ideas would be greatly appreciated.
Thank you,
Jacob
Thank you,
Jacob
