Getting The Shaft !

[ddtacm]

Hello All,

Still working on my 1977 Mercury 850, I finished the water pump swap on the lower unit and lined up the water pump tube hitting the stop point on the shaft while putting lower unit back on and slightly turned flywheel clockwise while pushing up on the lower unit as I always have and it is hitting solid. Will not line up and push up the final inch. shift spline is lined up but she wont go up. I have replaced water pump assy's on V-6 Mercs and V-4 Evinrudes also smaller 2 cylinder motors without any problem. Is there a step that I might be missing here? Any imput would be appriciated.
Thanks, Dan

 

[CharlieB]

Re: Getting The Shaft !

When all else fails, drop the lower, grab a flashlight and look up into the mid. Some models had a rubber sealing tube that fit on the vertical shaft to help seal the splines and keep them clean. Sometimes this 'seal' comes off and does not fall out of the mid, as you try to install the lower that seal gets pushed up and blocks the spline from going into the crankshaft. A wire coat hanger can be bent and used to fish out the offending seal. Put it on the shaft correctly then reinstall the lower.

 

[Maxz695]

Re: Getting The Shaft !

View attachment 17407740 hp without the carries assy but just to give you an idea. There is also a seal in the carrier that may have worked lose and stopping the drive shaft pin from going up into the splines. Charlies right take a flashlight and give it a good looking up in there and see what is interfering with the shaft View attachment 174076 There is a carrier that has a seal that goes on the end of the crankshatft just after the wear sleeve on the crank in the picture the carrier is not pictured but the seal can get distorted and then caught buy the tip of the driveshaft and push it up blocking the top of the slpines in the crank and not allowing the driveshaft pin up into it,s center hold.

 

[Chris1956]

Re: Getting The Shaft !

A 1977 Merc will not have the Oring seal. Driveshaft should mate with crank splines, with the turn of the flywheel while pushing the gearcase into the midsection. The upper and lower shift shafts are tricky to mate. There is a plastic fitting that holds the upper shift shaft in the center of the midsection. Maybe it has fallen into the gearcase side. Stick it back into the midsection with some grease. Wiggle the throttle arm to mate the shift shafts.

 

[ddtacm]

Re: Getting The Shaft !

Thanks Chris,
I checked the shift shaft splines and they were not lining up. I also discovered it had moved from neutral. There is very little movement
from neutral to forward and neutral to reverse. maybe an 1/8" to a 1/4". once I got the lower unit back to neutral I clocked the splines and was able to line them up and slip in the lower unit while slightly moving flywheel clockwise. She is back together and running very nice . Pumping indicator stream is very strong. Foward and reverse are working as they should. Thank you very much for the advise. I will submit pictures when I complete this project.

 

[Dave1027]

Re: Getting The Shaft !

While lurking I figured that was what the problem was.

This brings up my question. I believe my shop manual says to shift to reverse before LU removal and install.

 

[carholme]

Re: Getting The Shaft !

Before attaching gearcase housing to
the drive shaft housing, make certain
that shift cam (7-Fig. M12-61 or
M12-62) and the shift lever (on motor)
are in forward gear position on early
models and neutral position on late
models.

Gerry

 

[Chris1956]

Re: Getting The Shaft !

Gerry and Dave. I have always found that putting the shifter in neutral was the best way. Neutral is a single point on Mercs. This helps align neutral on the shift control with neutral on the motor. You can easily be one spline or more "off" if the motor is in R or F.
Just my experience.....

 

[Maxz695]

Re: Getting The Shaft !

Using revers is fine " if there is no cam" and it has trim tilt because lowering the unit in revers could cause damage to the cam. On my 70 hp i was having trouble getting it into full reverse (Prop locking both ways) It would lock one way then click the other between neutral and rev. Maybe my shift shaft twisted a bit or something but was able to clip the plastic spacer with dykes to let the shiftar bracket slide back far enough with cable adjustment to get the prop to lock in both directions. Just be sure to put the throtlle in neutral after installing the unit if it has a lock down cam in the LU.