'84 Merc 150 - throttle linkage problem

[MAtkins]

1984 Mercury Black Max XR2
Serial number: 6532700

I've been working on the timing on my motor and got it running like a top today.
After some time I was unable to get it up to speed to plane out.
I could idle and could get it just to the point where it should level out and take off but it wouldn't go any faster.

I literally ran the boat at WOT in the middle of the lake and went back to look at the motor (cowling was off).
The throttle arm on the motor was only half way over.
The carb linkage was not pegged open, it was about half way open.
The throttle control was all the way down (@ WOT).

I shut the motor off and pushed the throttle control to WOT.
I looked at the throttle arm on the motor and it was pegged, wide open.
The carbs were wide open too.
I started the motor and put it into gear.
I pushed the throttle control to WOT and the same thing;
the throttle arm and carbs were only half way open.

I did this whole procedure over and over just to make sure.
I could start it by just bumping the key and it would idle like a dream.
I could put it into gear and rev it up to a point, all with no problem at all.
I could not run it at WOT.

I could not get it to work right again.
What in the world is wrong?

 

[Dukedog]

Re: '84 Merc 150 - throttle linkage problem

1984 Mercury Black Max XR2
Serial number: 6532700
I shut the motor off and pushed the throttle control to WOT.
I looked at the throttle arm on the motor and it was pegged, wide open.
The carbs were wide open too.
I started the motor and put it into gear.
I pushed the throttle control to WOT and the same thing;
the throttle arm and carbs were only half way open.

I got nothin'. But will wait for a GOOD answer. Can't seem ta see any rhyme or reason ta be all good at rest and fall apart when its runnin'.....Never seen that before but no surprise. Its a Merc!!!