merc shift travel excessive

lostatsea · Apr 5, 2009

I have a 76 Merc with a single lever control box. Warm up lever works fine, shift lever shifts fine BUT shift lever has to be moved 90 degrees forward off of idle before any RPM increase is seen. No throttle response until I get 90 degrees past idle. Any ideas?

5150abf · Apr 6, 2009

Re: merc shift travel excessive

Not a Merc guy but sounds like either your cable stretched/broke or something on the engine came unhooked.

Could also be something in the control box let go.

I would pop the hood and make sure everything is right in there then watch it work as you move the throttle, maybe you will see something not right.

Did this happen suddenly(something broke) or over time(stretch) the answer to that question should point you in the right direction.

Chris1956 · Apr 6, 2009

Re: merc shift travel excessive

90 degrees off neutral puts the throttle handle in the 9 o'clock position (neutral is midnight). Normally full throttle operation would leave the handle in the 7:30 or 8 o'clock position.

90* off idle is excessive travel. If you push the throttle to it's limit do you get WOT? Carbs should be all the way open and timing fully advanced. If so, it might be OK.

capt sam · Apr 6, 2009

Re: merc shift travel excessive

was it always like this or is this new, sounds like something slipped or backed off like a friction screw.

lostatsea · Apr 6, 2009

Re: merc shift travel excessive

I just bought this engine and control box so I imagine it has been like this for some time. A friend believes it is a worn out control box as it is 30 years old and he has seen newer boxes already in ineed of replacement. I wish that I knew what is normal travel on this 76 box. Any ideas what current boxes would replace this box(i.e. model, manufacture) ? Dealer prices are going to cost big $, would like to find and order one myself if possible. Thanks.

Chris1956 · Apr 6, 2009

Re: merc shift travel excessive

Those MerControls can last a long time. I have a '77 Control box that Is just fine. It is now on a '93 Merc.

Check to see if it gives you WOT throttle. If not, it could be out of adjustment.

lostatsea · Apr 6, 2009

Re: merc shift travel excessive

Chris 1956, It may not be atWOT by the way it sounds but the warm up lever seems to get up to WOT. Definitely more RPM on the warm up lever than the shift lever. Running it in a 50 drum makes it difficult to go full bore. What and where might I consider making adjustments? How the heck does the shifter take over throttle control from the warm up lever. I have no manual and wont buy another sealoc one size fits all. Thanks for your help as I am at a loss.

Chinewalker · Apr 7, 2009

Re: merc shift travel excessive

I would look for wear in the control box, particularly the lugs on the cam that engage the shift arm. If it is worn, it will be apparent when you take it apart.
- Scott

Chris1956 · Apr 7, 2009

Re: merc shift travel excessive

It is not necessary to run the motor to see if it gets to WOT. Simply remove the cowling, advance the throttle all the way and see if the carbs are all the way open. The cold start lever must be all the way down for the throttle lever to function normally.

lostatsea · Apr 7, 2009

Re: merc shift travel excessive

Carb is not at WOT with shift lever advanced 90* (full travel). Butterfly is closed or nearly so.

Chris1956 · Apr 8, 2009

Re: merc shift travel excessive

OK, It would appear that something is broke or misadjusted. Can you verify that the shift and throttle cables are not switched? When you move the throttle handle forward from Neutral, the shift cable moves first, followed by the throttle cable. Have someone move the throttle lever and you observe the motor. The top cable is throttle, and the lower cable is shifter.

lostatsea · Apr 14, 2009

Re: merc shift travel excessive

Been rained out and computer went down but took boat to merc dealer and he is inclined to believe that problem is in the control box. Will be about seven days before I will know what resolves this problem. Will make a post as soon as I know what fixed it. All your efforts are appreciated as I have been lucky enough in the past to apply your tips and make repairs that saved me $. Thanks again for all your input. lostatsea.

lostatsea · May 4, 2009

Re: merc shift travel excessive

Got boat back from dealer. He rebuilt control box and replaced the throttlecable. Not in water yet but seems to be working fine in water barrel.

merc shift travel excessive

Cadet

Vice Admiral

Supreme Mariner

Master Chief Petty Officer

Cadet

Supreme Mariner

Cadet

Fleet Admiral

Supreme Mariner

Cadet

Supreme Mariner

Cadet

Cadet