Troubleshooting stiff throttle

[banderberg]

Mercruiser 3.0, alpha one gen 1 outdrive. Throttle on the boat has been very stiff since I bought it. Takes a lot of muscle to get the boat up to speed. I've removed the throttle and upper shift cables and they both slide easy with my hand. Shift linkage on the engine moves easily, and the carb is brand new, the throttle there moves easily. Not sure where my issue is. Thoughts? The control box itself has plenty of grease in it.

 

[Scott Danforth]

Have you checked the lower shift cable?

 

[banderberg]

Have you checked the lower shift cable?

I can move the linkage on the top of the engine where the lower shift cable connects and it's easy to move.

 

[matt167]

Seems you are talking about the throttle. Perhaps the carburetor is binding or, an internal tension adjustment in the control box is too tight. Did you buy one of those Chinese carbs? Throttle shafts could be too tight or you have the wrong throttle leg on it. Regardless, alpha gen 1 should have the long style throttle leg on it with a 3.0l

 

[banderberg]

Seems you are talking about the throttle. Perhaps the carburetor is binding or, an internal tension adjustment in the control box is too tight. Did you buy one of those Chinese carbs? Throttle shafts could be too tight or you have the wrong throttle leg on it. Regardless, alpha gen 1 should have the long style throttle leg on it with a 3.0l

The carb is from National Carburetor so no, not Chinese I wondered about the internal tension adjustment, is that just the nut that secures the cable or something else?

Here's a photo I took for reference:

 

[banderberg]

Seems you are talking about the throttle. Perhaps the carburetor is binding or, an internal tension adjustment in the control box is too tight. Did you buy one of those Chinese carbs? Throttle shafts could be too tight or you have the wrong throttle leg on it. Regardless, alpha gen 1 should have the long style throttle leg on it with a 3.0l

Can you help me with the internal tension adjustment you mentioned? Where is it and what do I need to do? Installed new cables and it's as stiff as ever, maybe more so.

 

[matt167]

There should be something in the inside by where your hand is that provides tension to the throttle cam.. show a picture of the entire control.

 

[tank1949]

The carb is from National Carburetor so no, not Chinese I wondered about the internal tension adjustment, is that just the nut that secures the cable or something else?

Here's a photo I took for reference:

View attachment 400207

Buy lots of brake cleaner and a large flat pan and start cleaning. At least eliminate all the old grease that has gotten hard. MC makes a special Teflon grease. Use it.