Trouble "revving" 1970's Mercury 200 20 hp motor

[Hiscopilot]

13 yo son just purchased a boat with this motor. It appears overall to have been well maintained. Starts easily, pretty clean, impeller/ water pump and carb replaced this season, etc. However, the tiller handle plastic grip and tension cap was missing. The rod remaining was slightly bent. We replaced the handle and started the motor to check it out. The handle turns but very little. It feels like it is restricted somehow somewhere in the mechanism. Looking under cowl, I was able to determine the ability to to get gas and such is not a problem. I followed the ?linkage? And revved it manually. I tracked back and it would seem the rod coming from the handle into the motor, perhaps into a pinion gear is unable to turn from the handle. I used An open ended wrench and gently turned it as my son turned the handle. It turned fine with the wrench but still the handle will not turn it. Function all appears fine except for this part. Any ideas? What next? How difficult to repair? Also, the prop seems to turn a lot in neutral. That appears consistent across a few videos I have found online but I would like to know if that is "normal"?

I am very mechanically minded and feel like I can help him learn a lot with this relatively simple motor.. But I need to make sure I am on the right track as I go. Really thank you in advance for any and all help.

 

[flyingscott]

Need serial # The throttle probably won't open all the way unless it's in gear. Did you line up all the linkages correctly to get full throttle motion. The prop will turn freely in neutral, take a video of the problem

 

[Hiscopilot]

Video of motor running. The problem didn't really translate to video- you couldn't really tell other than no rev when turning handle. Later when there's someone else around who can video while we do it,I will grab another clip. http://s7.photobucket.com/user/scraps_in_time/media/IMG_2119.mp4.html

Serial 8548098. Didn't seem to fit ranges found online. Or at least according to my son.

Here are some pics of where I suspect the problem lies:
http://s7.photobucket.com/user/scraps_in_time/media/image.jpg5.jpg.html
http://s7.photobucket.com/user/scraps_in_time/media/image.jpg4.jpg.html

I am sure there is nothing visible that tells you where the issue lies.
We are going to work with it today, hopefully better video and more info for you later. If you have anything specific for us to look at/ for please do tell me.

Thank you for your reply.

 

[Chinewalker]

There is a stop in neutral that prevents over-revving with no load on it. In gear, you should be able to advance the throttle further.

 

[Hiscopilot]

Okay, so new factor in the problem. Because we could feel the notch, we thought it was shifting okay but when we got it on the water, it was either running hard and "driving" in neutral or it was in fwd and wouldn't increase to full speed. My step dad rigged some pc of metal to be able to increase throttle, but it would not allow it to go super fast. It will not go in reverse. The switch moves but the motor does not shift. I tried to get video, but still think it's poor.
http://s7.photobucket.com/user/scraps_in_time/media/IMG_2120.mp4.html
http://s7.photobucket.com/user/scraps_in_time/media/IMG_2121.mp4.html
That piece of the puzzle changes things maybe a little. Am I wrong in my understanding that the assembly of the throttle shift control (which is the name I found for the part I assumed was the culprit) would affect the ability to shift gears.? We are willing to use this to learn, so I really appreciate your patience with me.

 

[Chinewalker]

Almost sounds to me like it might be running on one cylinder. Try a cylinder drop test - removing one plug wire at a time and noting changes in how the motor runs. Those twin-cylinder Mercs will run surprisingly well on one cylinder.

Also, with the throttle fully advanced (motor not running) is the timing being advanced full? Is the carburetor butterfly opening all the way? Should be able to check these visually...

 

[Hiscopilot]

It may be a couple of days before I can tinker further, thanks for the advice. If it is running on one cylinder, I am going to be showing up on the guys doorstep!

 

[Hiscopilot]

Could you perhaps explain to me how to visually check the timing? Butterfly and cylinders okay.

 

[Chinewalker]

Not much to check on the timing on those. Unless someone has monkeyed with the linkage adjustment, it should be as set from the factory. Did you do the cylinder drop test? Removing one plug wire at a time and noting one happens?