No reverse after changing impeller

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dmccrae75

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I had to change the impeller on my 1978 mercruiser 4 cylinder i/o. After putting the lower unit back together, I have no reverse. Works great otherwise. What did I do wrong?
 
Don S

Don S

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Re: No reverse after changing impeller

It sounds like you did this with the upper still on the boat, Did you have everything in forward when you put the lower back on? Did you have the washer on the shift shaft? Did the splines line up?
 
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dmccrae75

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Re: No reverse after changing impeller

the upper was still on the boat, everything went back together easily. I have full motion in foward, in reverse the motor throttles up but the gear won't engage.
 
Don S

Don S

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Re: No reverse after changing impeller

dmccrae75 said:
the upper was still on the boat, everything went back together easily. I have full motion in foward, in reverse the motor throttles up but the gear won't engage.
Click to expand...

You forgot to answer my questions.

Did you have everything in forward when you put the lower back on?
Did you have the washer on the shift shaft?
Did the splines line up?
 
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dmccrae75

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Re: No reverse after changing impeller

sorry, the splines lined up, the washer was on the shift shaft, but I did not have it in forward. I had it in neutral. gonna take it apart again today and try forward. thanks.
 
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dmccrae75

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Re: No reverse after changing impeller

I dropped the unit again, put the motor and lower unit in forward, now the unit won't go back together. The drive shaft won't turn at all to line the splines.
 
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dmccrae75

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Re: No reverse after changing impeller

When I turn my shifter shaft all the way clockwise and hold it in place, the prop turns clockwise (forward) and stops when I try to turn it counter-clockwise, but if I spin the prop clockwise at all without holding the shift shaft in place, it disengages and allows the prop to spin both ways again. Its the same in reverse.
 
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stonyloam

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Re: No reverse after changing impeller

dmccrae75 said:
When I turn my shifter shaft all the way clockwise and hold it in place, the prop turns clockwise (forward) and stops when I try to turn it counter-clockwise, but if I spin the prop clockwise at all without holding the shift shaft in place, it disengages and allows the prop to spin both ways again. Its the same in reverse.
Click to expand...

That is how it is supposed to work;). Shift into forward, turn the prop CCW until it locks then put a bungee on the prop to hold it in place. If you need to turn the shaft a little to line up the splines, turn the prop CCW. Think about it, when the engine is running and the boat is in forward, the prop is being rotated clockwise, and the force against it is acting in the CCW direction, the direction it locks.
 
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dmccrae75

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Re: No reverse after changing impeller

Completely frustrated now. Everything works fine while apart, as soon as back together no reverse. I've put it back together in forward, reverse, and nuetral numerous times. Each time I get the same thing, no reverse. I'm beginning to wonder if the shift shaft or the sleeve that joins the two shafts together might be worn. Any more advice?
 
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chucks440

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Re: No reverse after changing impeller

Just went through this yesterday.. If it worked before,its gotta work after taking apart. The board members on here know their stuff so I think they can get you straightened out. Like Don said,,,shifter in forward, gear shaft turned clockwise to lock the prop from turning counter clockwise and it should go! I,ll be watching.....
 
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dmccrae75

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Re: No reverse after changing impeller

back together again, shifter moves fine both directions, still no reverse. When in reverse, I get a light clicking sound with the prop spinning boths ways. I'm beginning to think that it may only need to be adjusted but I don't know where the adjuster is at. The shifter by the motor engages completely, is there another adjuster after that?
 
Don S

Don S

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Re: No reverse after changing impeller

I think you need remove the upper, and install the upper onto the lower in order to get things right and be able to check things out as you go. As you see, this short cut of pulling only the lower is not much of a short cut.
 
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dmccrae75

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Re: No reverse after changing impeller

just took the upper off, the piece that moves the shift shaft(sorry don't know what its called) needs to be replaced. The teeth are so worn on one side that it won't engage reverse.
 
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