1979 Mercury 40 hp low throttle in forward gear, high throttle in reverse gear. Help

[Roo87]

I recently got a boat and motor from a friend of mine that hasn't ran in about five years.
The motor had the lower unit take off to replace the impeller and was never put back on.
I installed the lower unit back on the motor after replacing seals and gaskets in water pump.
I made sure lower unit was in neutral as well as the controls when installing LU. So I got the LU installed, reverse and forward gear all work. Only thing that didn't seem right was the bar that sits on top of the cam didn't sit on there, is that a problem?
Cleaned and overhauled carberator. New spark plugs spark is blue in color and has plenty of spark. New fuel lines. Checked compression 115 both cylinders.
Engine will throttle up just fine with throttle control lever.

So the problem I have is when I shift into forward it acts as though it is reverse speed, not reaching full throttle, and when I push the lever all the way forward it barely engages the throttle on the side of the engine. I can push the controls all the way forward then on the side of the motor manually throttle up the engine but can't go full throttle using only the controls. When I put it into reverse I can bring the control lever back all the way and it acts as though I have full throttle. Reverse engages throttle on the side of the motor all the way to full rpms.

What could be causing this?

 

[jimmbo]

Remote control unit taken apart and not reassembled correctly

 

[merc850]

Do you have the throttle cable on the shift connection and vice versa?Someone else had this same problem because of that.

 

[Roo87]

Thanks for the response. The control box I have, has the shift lever on left side of the control and the throttle lever on the right side of the control. You don't have to push any buttons to engage just the throttle.
I took the throttle cable loose from the engine yesterday and whenever I shift it into forward and advance it all the way the throttle cable moves like it is supposed to, stiff, but it does move in and out like it is supposed to. When I attach the cable back to the motors throttle assembly back to square one, it won't engage throttle all the way. It will in reverse but not forward.
Looking inside the control after taking it apart I don't think the cables are swapped bc if they were I woulr think it would engage the throttle first instead of the shifter, but I am a novice when it comes to boats.

Thanks yall for the input.
I also ordered new cables thinking maybe that was the cause but I don't know.

 

[merc850]

Maybe you have the wrong box. This was used for quite a few years on Mercury outboards and replaced the 2 lever OMC type.

 

[Roo87]

That looks just like the one I have except a lot newer.

 

[Roo87]

I will try to get some pictures posted of what I have this afternoon.

 

[flyingscott]

Put up a video if you can of the linkages on the motor working when you move the throttle. Revving up in reverse is just like revving it up in neutral useless as a diagnostic tool. I will tell you why when it revs up to fast in reverse the prop cavitates so essentially it is running in air easy to rev up. Causing people to think it's working in reverse and not in forward when it's not.

 

[Roo87]

No Title

Here are the controls that I have.

 

[Roo87]

Here is the only video I have right now that I took the other day. When the throttle moves the first time that is in reverse when it engages and the second time is when I have it in forward and I am trying to engage it.

 

[jimmbo]

Can you post a video of both the shift linkage and the throttle linkage moving when shifted and as the throttle is advanced?

 

[merc850]

The shift/throttle lever is all in one; the big one - the little one is for fast idle when starting motor, if that lever is sticking up it will interfere with the operation of the controls. Raise the little lever to vertical and push and hold choke while turning key; when motor is running lower the little lever.

 

[BlackBetty]

What ever happened here? I have the same problem on a 650. Recoup in reverse only and not in forward. Has anyone attempted a counter rotating prop to fix? What else can be done?