78 260 Mercruiser driving me crazy

hey guys, I don't know if any one can help . . but I will greatly appreciate anything at this point . . . I have a 1978 Searay with a 260 Mercruiser. . .I have done the following. . .1. replaced remote shifting cable and throttle cable and control . . .2. replace impeller 3. replaced shift shaft bushings. . . 4. replace lower shift cable (old style with new style) . . .now my problem. . .when i sterndrive back on I can not shift into reverse. . .I have taken great pains to make sure the lower unit is in drive, using a bungee cord to keep prop in gear . . .I have take lower unit off 5 or 5 times thinking that I had missed the unit coming out of gear . . .after all the work I now find that the shift shaft is hanging up and not going into to reverse. . .I can get the shaft to shift into reverse (with outdrive on boat) by forcing it with a screw driver from under the outdrive, only have to turn it a 1/16 of an inch . . but the resistance is enough that when I try to shift into reverse with the remote the cut out switch kills the engine. . .I'm lost . . any thoughts ?

new shift cable not seated all the way, remove the drive and reinspect everything. You replaced the cable with a new complete kit, correct?

Did you do the shift cable adjustment completely and correctly, where the shift interrupter switch is located?

Yes I did. . Is it possible that I did not insert the new cable (the brass fitting) far enough into the bell housing and that is causing the shift lever to hang up on the plastic rod (that extends off the brass fitting) and not allowing a full shift into reverse ?

This issue is not easily answered from the internet. But is a very common problem with older alpha one gen 1 systems.

Several things at play here.

1. the 9/16" hex brass fitting for the short shift cable must be screwed almost ALL the way in. typically no more than 1/16" between hex and housing.

2. when you replaced the shift bushings are you refering to the ones in the gimbal housing? If so if the bottom one is not in the correct location (hieght) it can cause this issue. if it is to high the vertical shift shaft in the gimbal housing will be to high when engaged with the bronze shift arm in the outdrive.

3. The vertical shaft in the gimbal housing, At the bottom where the U shape is, could be bent due to the drive bieng removed without the shift control in forward gear. This is very common and it also can and does cause the bronze shift arm in the outdrive to be worn and/or bent also.

I just went thru this on a boat two weeks ago.
Replaced the bronze shift arm in the outdrive, the stainless steel vertical shaft in the gimbal housing and the bell crank which attaches to the vertical shaft due to the screw/pin having to be drilled out taking the bell crank out with it....

Cost was about $180 for parts and corrected the problem. The bronze shift arm was very worn and slightly bent and the stainless steel vertical shaft was very bent at the U. The bellcrank broke when drilling the screw/pin out and was callateral damage.......

Thanks for getting back to me...It took awhile to get the parts that you discussed....now I have a question you might be able to help with. . . . as I was installing the new parts and was about to put the lower half back on . . .I was turning the shifter to lock the prop in forward . . .as I was doing this I noticed that the shifter moved from forward to reverse, but there seemed to be a bit of resistance when turning the shifter from forward to reverse.....could this be the what causing the hard shifting when everything is together . . .and what would be causing this ? Any thoughts would be appreciated ! !

Possibly the shift spool in the lower unit..........it is scored and worn causing it to move roughly inside the prop shaft.

Not much you can do or we can do from here..........may need the lower dissasembled to see what is going on......

one more question, is appears that the lower shift shaft will not properly go into the intermediate shift shaft when connecting the lower half to the top half. . . It appears the splines on the lower shaft are in pretty bad shape (my fault Im afraid) and the intermediate shaft will not go completely down on the lower shaft. Thus, this is causing the shifting process to bind up when the two halves are connected. So my question, do you have to take the lower unit apart to install a new lower shift shaft, or can you pull it out if you remove the lower shaft bushing in the lower half ? Thanks for the help

remove shift shaft bushing, (requires a special tool) and the shaft will pull right out.........no special orientaion of shaft