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Ask Dominick Your Own Question
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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2000 mercruiser 454 mpi3, starts and runs fine until 2600

Customer Question

Hi. 2000 mercruiser 454 mpi3, starts and runs fine until 2600 rpm no power above that. Compression good injectors clean timing ok fuel tank ok fuel ok. Changed sensors iac and throttle position. No codes on tester according to marina tech. New clean fuel filters. Checked for vacuum leaks checked grounds even swapped control computer engine to engine no change no alarms we're stumped
Submitted: 2 years ago.
Category: Boat
Expert:  Jason replied 2 years ago.
Hello my name is ***** ***** am I speaking with? Does the alarm system work in the boat, when you turn the key to run, does it beep each time? What does each cylinder read for compression? Did you check fuel pressure at idle, or with the boat at the highest speed it can hit?
Customer: replied 2 years ago.
Hi I am JoeNo alarms when turn key. Compression 140 to 145 across all cylinders, fuel pressure I think was 43 psi I know the tech had the computer connected both at idle and under way no codes, no fuels pressure problems showing.
Expert:  Jason replied 2 years ago.
Hi JoeHave you ever seen this boat hit more than 2600 rpms?
Customer: replied 2 years ago.
No its was a reposession. We are checking the tranmission ratios engine to engine later today. Props we think are same. Engine runs fine no smoke, good idle comes up fine then hits a wall. No alarms. We also ran it without flame arrestors no change.
Expert:  Jason replied 2 years ago.
That is what I was going to ask you next is if you could get me the gear ratio on the stern drive.
Customer: replied 2 years ago.
Its a velvet drive unit the ones that reverse the engine. Were going to check that later today.
Expert:  Jason replied 2 years ago.
Okay I'll wait for the model and ratio on that drive. If you can get the size of the prop as well that would be helpful.
Expert:  Jason replied 2 years ago.
Good morning. Any luck on that ratio?