Merc 50 control box

[tmcalavy]

Hey, I like this forum. Could anyone tell me where/how to get ahold of a diagram/schematic/manual that will show me how to troubleshoot/replace the cables that go from my Merc 50 hp outboard up to the control box? Coming back to the ramp this last weekend, the forward throttle developed a lot of slop. Don't get any forward throttle response until the throttle is about 3/4 forward. This is a mid-70's Merc 500 outboard with a Merc-control side-mount control box. The box has key/switch on the rear, and a black choke button just above it on the top of the box. One throttle/shift control and an idle/throttle lever between the box and the boat mount. Any help would be appreciated.

 

[skydawg]

Re: Merc 50 control box

Hey Tim, I had the same thing happen to my merc 500 and never did find out what happened. However, I was still able the get WOT with the control. I'm interested to see what you find out.

 

[12Footer]

Re: Merc 50 control box

Hi, Tim. The manual is lacking when it comes to a good pictorial of the control linkage, frankly. I would still get a shop manual for it,as the timing pickup on the linkage and forard/reverse will probably need to be re-adjusted after removing the slop. But the best meathod is to have someone operate the throttle, engine-off, while you observe how the linkage works on the engine. I suspect this is where the problem actually is, as opposed to the control or cables.<br />Look for a link or arm that has vibrated loose back there.

 

[skier]

Re: Merc 50 control box

tim Mc:<br /><br />Our family had a '71 Merc 1250 and the same control box you have and that same thing happened, I never found the problem, but I ran the boat for another 15 years like that, Never had a problem. I even took it to a few mechanics and they couldn't find a problem. As long as you can still reach WOT, you should be fine.<br /><br />Craig

 

[tmcalavy]

Re: Merc 50 control box

Well, that's the prob. You see, I have what seems to be excess power in reverse compared to forward and only a portion of the forward throttle I once had. Can't get anywhere near WOT. But I got lucky and found a Merc control box manual on Ebay. It is on the way, so I'll struggle with it myself and then probably drag it off to the boat guy. I pulled the cowl and worked the throttle lever while watching the motor. Can't see the cable connections then of course, but I can tell the dist. is not advancing as far in forward as it does in reverse. Guess I'll get greasy and learn more about it this weekend. Any other suggestions/tips??

 

[tmcalavy]

Re: Merc 50 control box

Okay folks,<br />Figured out how my throttle cable works in both gears back at the motor, after pulling control box apart and rechecking it for cable problems. I can stand at the throttle, put it in reverse and the dist. moves/advances more than when in forward. Is this right? Or do I need to adjust my forward throttle linkage. It'll run like a scalded ape in reverse, but there is a lag in forward throttle response. I'm baffled.

 

[skier]

Re: Merc 50 control box

tim Mc:<br /><br />The distributer is only the first 1/2 of the throttle. After the distributer stops then the butterflies on the carbs start to move. Sounds to me like you have something binding in the control box. <br /><br />Take the throttle cable off at the motor and try full throttle at the box, if you don't get full travel then it's in the box, if not then the motor but I doubt that cause the motor doesn't care what gear your in.<br /><br />Let us know what happens.<br /><br />Craig

 

[tmcalavy]

Re: Merc 50 control box

Thanks. One question, though. How does someone with no experience or frame of reference with throttle cables determine whether they're getting full travel or have a bad cable, once they pull the cable off the motor? Any tips appreciated.

 

[skier]

Re: Merc 50 control box

tim:<br /><br />With the cable disconnected from the engine, move the linkage (On the motor) to see if you can get to WOT. To check this look into one of the carbs and see if the butterflies are all the way open. If the engine can get to WOT then push the control box lever to WOT and see if you can get more travel than you did with it attached to the motor.<br /><br />Craig