Alldodge thank you for your answer.
From what I can understand you're suggesting that the engine had an incorrect ecm installed. I cannot argue with this, as I purchased the boat/engine after 15-20 years of storage.
Attached a printscreen of the ecm listed on mercury marine parts catalog (part numbers 807650t2, 861078t1, 806720t7) for my serial number. Do you know which delco ecm is it?
I have checked plugs, compression and firing order, replaced distributor with a new one. I don't know what cap and rotor means!
Kind regards,
Kostas
This new distributor, do you have the make and model number. As to the engine serial number, let's focus on the head design. Underneath the valve covers there are casting numbers, they will identify your engines needs.
Your current setup may well work, it just needs to be setup correctly. Beyond the head casting numbers, timing a Mefi engine is very spefic, can you post exactly the procedure used?
While you do not have diagnostic software you can do some foundational testing.
You will need a timing light, and a timing tape. The tape will allow you watch the timing advance as you rev the engine up in neutral. If the engine does not advance or jumps around under high rpm there is your problem. A video of you doing this would be all telling. A note here, the timing marker should start at 10 degrees initial timing and advance to at least 26 degrees by 3000 rpm.
If the timing does advance, the take off the dust cover and point the timing light at the injectors. They both should display a round conical spray pattern. This pattern should be uniform and constant...As you approach 2000/2500 rpm pay close attention to both injectors.
A timing light will capture the the injectors spraying in almost a still picture like image.
Sounds tedious but it is part of the process.
At this point do not connect your engines knock sensors, they only muddy the waters.
Below is a timing tape, and you need one designed for your spefic 5.7
Free Shipping - MSD Timing Tapes with qualifying orders of $109. Shop Timing Tape at Summit Racing.
www.summitracing.com
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