1984 mariner 50hp

[Lyle Bourgeois]

Motor starts and idle fine i rebuilt carbs and fuel pump. Boat ran at full speed for about 25 minutes, Started sputtering and started to run at about 3/4 speed. It is running fine but will not run at full speed, every now and then it tries to go to full speed .Gets out of water good. just wont get to full speed, can you help with this

 

[racerone]

Compression test values should be posted.-------Does spark jump a gap of 3/8" on all 4 leads ?

 

[Lyle Bourgeois]

When you say 3/8 in Is this from looking at plug when firing

 

[racerone]

No you need to find / make something that presents a 3/8" gap. This forces the ignition system to perform to it's designed capacity.