89 Force125 butterflies not fully open at WOT

[Glenn Iverson]

Been trying to solve this for awhile now. I have the throttle arm scribe mark lined up with the cam so that it intersects. Throttle stop screw just touches engine block. Nice 700 rpm idle in gear & even acceleration without bogging. Problem is with throttle fully open the carb butterflies are 3/4 to 4/5 open at wot. I get 45 -4700 rpm & 37mph with my 89 Arriva 20 ft. boat with a 17 pitch prop. Before I would extend the throttle linkage arm to get the butterflies to open & could get 5000 rpm & 40mph but would suffer from flat spots during acceleration & loading up the carbs with gas. It runs well now just not achieving full throttle. I have a timing light & remote starter switch. I will check the timing this weekend. Will static time to 28% WOT if not already there. If I find the timing happens is retarded will advancing to 28% WOT help the butterflies to open atl the way? I suspect the previous owner may have played with it.

 

[Glenn Iverson]

I might add when I disconnect the throttle & shifter cables & move the throttle tower by hand all the way to Wot the butterflies do open all the way flat. It is as if the shifter is limiting my throttle.

 

[jerryjerry05]

If it can't be adjusted at the linkage??? then the shifter could solve the problem.
​They come with 2-3 extra holes and maybe changing the hole might give you the extra throw??

 

[Glenn Iverson]

I was thinking the same thing. I have one of those US marine flush mount control boxes. If I can figure out how to get it out of the side panel I will try that.

 

[pnwboat]

Depending on which control you have, the black plastic cover is split in two. Each piece just slides off exposing the mounting bolts and mechanism.