No throttle when shifted into reverse.

[oldmanwinter]

I have a 1978 115hp inline six Mercury outboard. Shift and throttle cables have been replaced (others were bad). I now have close to full throttle in forward but when I shift to reverse, the prop spins, but I do not have any thrust to move the boat with. If I pull the lever all the way back, the boat will reduce rpm and die. I have the clymer shop manual but it does not address this issue. I would appreciate any help or insight to this matter. Thanks.

 

[CharlieB]

Re: No throttle when shifted into reverse.

Is it possible the cables were installed incorrectly, switched at the motor end during replacement?

Disiconnect both cables from the motor. While disconnected shift the motor manually into Reverse, you may need to roll the prop with your foot so the engagement dogs will align and the shifter fully move into position. Great, now does the prop lock to the motor so if you stand on the blade it won't turn or causes the motor to turn over? If so that is good.

Shift the control arm into Reverse, see which cable extended, this is the shift cable, reattach it. Reattach the throttle cable and pull the throttle back to WOT Reverse, look and see if the throttle opened WOT. If it did that is fine.

Shift everything back to Idle, Neutral, attach the hose and start the motor, once running check shifting, you should hear it solidly drop into gear when you shift, The throttle should work, move it carefully, you do not want to over rev it.

Launch the boat and recheck everything.

 

[oldmanwinter]

Re: No throttle when shifted into reverse.

Is it possible the cables were installed incorrectly, switched at the motor end during replacement?

Disiconnect both cables from the motor. While disconnected shift the motor manually into Reverse, you may need to roll the prop with your foot so the engagement dogs will align and the shifter fully move into position. Great, now does the prop lock to the motor so if you stand on the blade it won't turn or causes the motor to turn over? If so that is good.

Shift the control arm into Reverse, see which cable extended, this is the shift cable, reattach it. Reattach the throttle cable and pull the throttle back to WOT Reverse, look and see if the throttle opened WOT. If it did that is fine.

Shift everything back to Idle, Neutral, attach the hose and start the motor, once running check shifting, you should hear it solidly drop into gear when you shift, The throttle should work, move it carefully, you do not want to over rev it.

Launch the boat and recheck everything.

Thanks for the information, I tried what you suggested, unfortunately, the cables were in the correct place. I will try and post some pics of what moves so as to give some better idea. Thanks for your reply.

 

[GA_Boater]

Re: No throttle when shifted into reverse.

Maybe the remote was assembled with something in the wrong place inside.

Welcome aboard, oldmanwinter.. You know most of us don't like Old Man Winter - cuts into our boating time. :joyous:

 

[CharlieB]

Re: No throttle when shifted into reverse.

You still need to disconnect the cables and test the control arm movement with the cables disconnected.

It is always possible to have either cable adjusted too tight, this places the control arm in a bind and makes cable movement difficult.

If both cables move correctly while disconnected, then reattach but be weary of how much tension is placed on either cable, adjustment may be needed.

I am wondering if the shift cable is set too far towards Forward, so it does not shift far enough towards Reverse.