Mercontrol problems 85 hp model 850

[Curtis W.U.]

I have a Hydra sports with an 85 hp model 850 mercury 2 cycle engine. It has a 2 lever mercontrol. The warm up lever will increase idle but the shift/throttle lever does not increase throttle. I have taken apart the control box and found worn cam slot and brass roller follower. The shift lever does shift into gear but only increases throttle a small amount with the warm up throttle completely forward. The shift lever does shift into gear as soon as it is moved forward a small amount. I know this is about 30 years old so it probably is worn out and obsolete. Is there after market replacements for this control and if so which one would be best?

 

[GA_Boater]

Welcome aboard.

My MerControl, 52 years old, acts the same way. With the warmup lever raised you can't move the throttle forward after shifting to forward. I think you are describing a normal condition.

Lower the warmup lever before trying to shift, especially into reverse because the motor will go to almost WOT - Not safe.

 

[Curtis W.U.]

Thanks, You are correct in that throttle/shift will not advance throttle with warm up throttle in up position. This is the first Bass boat that I have owned and since it is used, with no instruction manual I had no idea it operated this way. I took boat out yesterday and throttle worked like it should. But lol could not get the trim to lift motor so I could load boat. I think it is low on fluid. I had a fellow fisher man help me that was very familiar with this type boat and he released the manual pump valve (which i did not know it had lol) and we raised it by hand which was easy enough just got a little wet doing it lol. Darn that water was cold standing waist deep.

Thanks for the help

 

[merc850]

If the pump motor is working then maybe you should bleed the system