86 Evinrude XP 150 looses power at WOT

[herman07]

My 86 XP 150, model number E150STLCD, looses power at full throttle after getting warm. New plugs, coils, one new power pack, spark on all six and compression good. Had it on the water today. Initially had great hole shot, ran up tp 5200 RPM for about 10 minutes. While at full throttle, rpm dropped to 4000. No more good hole shot, barely dragged itself up on plane.

Any thoughts on what needs fixed? I'm scratching my head.

Thanks in advance for any assistance.

Herman

[ChampioNman]

First thought would be to check compression on the motor, next check the head temps, next check the sync n link. Make sure H20 pressure is good. Then timerbase,,or stator.

[TritonAL 186]

You could have one of the packs going bad, When it gets hot it shuts down one or two cylinders causing your outboard to operate only on four or five cylinders. Also a bad coil or coils will do the same thing.

[herman07]

I pulled the port pack and replaced it with one I replaced last year. It ran better, but could still hear one cylinder missing occasionally. It will get up on plane now, but the hole shot is more of a drag than a shot. I can hear the one cylinder miss then pick up until it got up on plane. Once I had it trimmed out and running on plane, it seemed to run pretty well at about 4200 RPM.

I will replace the pack with a new one and hope I got it right.

Thanks for the help.

Herman

[Sumo]

I am having the same problem right now on my 90' 175XP. I am leaning more to a bad wire then a bad coil but it would be interesting what you find out about yours. I should get my plug wires tomorrow, we will see.