mercruiser impeller problemsl

cds

Recruit
Joined
Sep 17, 2004
Messages
1
I have changed impeller & upper & lower housings on my 1986 Mercruiser 170 hp 4 cyl. alpha 1 I/O & cannot get lower unit splines to line up with upper splines. With shift control lever in foward the foot coupling is not pointing foward but off to one side so that shift lower brass shift spline foot will not line up with upper. After moving shift control lever in boat it still does not move the foot towards any position.I have moved shift lever brass spline clockwise & counterclockwise while keeping pressure on prop ccw & cant seem to get things line up properlyAny suggestions or step by step procedures? Thanks
 

Winger Ed.

Chief Petty Officer
Joined
Mar 24, 2004
Messages
649
Re: mercruiser impeller problemsl

Put the shifter in FWD.<br /><br />Rotate the long vertical drive shaft clockwise (I think) while holding & pushing the little shift paul on the lower unit towards it facing straight.<br /><br />When it moves over and clicks in, and you're rotating the shaft, the prop will start turning in the FWD direction. Then it will fit.<br /><br />Remember:<br />You're using all the original gear case parts.<br />They fit fine when you took them apart,,,,<br />You didn't break anything,,,,<br />so you know they'll fit back together also.<br /><br />.......<br /><br /><br />Also, making sure everything- water pipe, shift couplings, and bolts are lining up, you may have to rotate the prop against the clutch dogs-- it will not go 'clickety click' and free wheel as it passes over them, but rather as if you were trying to rotate the engine with the prop. That will get the drive shaft splines lined up as it goes up into the upper case. <br /><br />As you're turning the prop and bearing up on the lower unit---You'll feel it when they line up, and the lower case should go on up and bottom out. Be real careful when you let it back down enough to get the side nuts on!<br /><br /><br />It may also be easier to hold and set the lower unit back up into the upper case if you tilt the outdrive up as far as it will go. Maaybe even lower the front of the boat/trailer too. For some folks, sliding the lower unit more or less sideways is easier than trying to line everything up while holding and lifting the lower unit straight up into place.
 

steve n carol

Chief Petty Officer
Joined
May 8, 2004
Messages
459
Re: mercruiser impeller problemsl

if the upper is off of the gimbil housing, then put the two pieces on a bench so that you don't have to fight gravity. <br />I did have the water pipe mis-align once. that was tough. You may want to use a bungee chord to maintain pressure on the prop to keep the shifting pawl in the 'forward' position too...sl
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,349
Re: mercruiser impeller problemsl

From the sound of it your not in fwd position on the control box.make sure you didnt push in the idle button.the slotted part must be straight to install the drive. if its the shoe on the lower that wont line up the lower was misassembled. full fwd gear should have the shoe going straight also.
 

djvan

Chief Petty Officer
Joined
May 3, 2003
Messages
411
Re: mercruiser impeller problemsl

Originally posted by steve n carol:<br /> if the upper is off of the gimbil housing, then put the two pieces on a bench so that you don't have to fight gravity. <br />I did have the water pipe mis-align once. that was tough. You may want to use a bungee chord to maintain pressure on the prop to keep the shifting pawl in the 'forward' position too...sl
Ditto on the bungee cord, they usually slip out of gear unless some sort of tension is maintained.<br /><br />DougV>
 
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