Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

[SC_Regal]

I have a 2000 Mercruiser 5.0 EFI with Alpha I Gen II. I have had an intermittent shifting problem for some time - shifts into gear, forward and reverse, without problem. I changed the lower shift cable and adjusted as instructed in OEM manual. I tested it with boat tied to dock and it worked perfectly, took it out and I again had shifting problems. I went through the trouble shooting section of the manual, no excessive play in the lower unit shift cable. The throttle cable travel is less than the specs - 2 6/8" , not the 2 7/8- 3 1/8 that is called for.

Could this be the problem? Is there any way to tell if it the cable or the throttle control unit. Could the shift interrupter switch give an intermittent problem.

The manual says if the travel distance is out of the specs to replace the cable and/or the controller. I plan to replace the cable and wanted to get some advice.

 

[SC_Regal]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

Sorry, I did not fully explain the problem. I have trouble shifting out of gear, either forward or reverse. The engine never dies, it just gets difficult to shift into neutral. Once in neutral it shifts into gear fine, and will usually work fine until I fully advance the throttle - I will then have the same problem.

Sorry about the first post.

 

[SC_Regal]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

bump

 

[ziggy]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

can ya shift it manually, with the lower shift cable detached. run the cable in and out and see if yer shifting proper at the prop. fwd.= ccw prop lock. rev.= cw prop lock. the cable should run nice and smooth with not much pressure to run the components assosiated...
if so. i'd recheck how ya got it set at the shift plate.... perhaps ya need to go thru the full adj. but i'd start at the lower cable adj. 1st...
what certainly is happening. is that yer shift interupt is not actuating at the proper time. like, right when yer trying to come back to neu. usually a sign of a bad lower cable. but ya got a new one. so, confirm it's easy at the cable, confirm it's propoer at the shift plate. then i'd move on to the remote cables.....

 

[Don S]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

The throttle cable has nothing to do with the shifting. If you are having problems with it coming out of gear, watch the Y shaped plate that activates the shift interrupt switch and see if it is actually operating the switch. You could also have a bad shift interrupt switch.

 

[SC_Regal]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

Lower shift cable operates smoothly and works well when removed. The length is exactly 6". When installed, with it all the way in the bottom of the slot, it won't lock the prop in reverse. As per the manual, I moved the cable attachment up the slot until reverse engages. I don't feel like the shift interrupter switch (plunger type) is centered in the Y or groove - it seems that it is just off 1/64-1/32". Is there a way to center the switch? Thanks

 

[Don S]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

That 6" dimension is a starting point and may have to be adjusted depending on the other adjustmens.
Get the manual and follow the complete process in section 2A.

 

[SC_Regal]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

I did, and that is where I came up with the throttle throw distance. In the trouble shooting section on shifting - I think step 11 or 12 - it says that if the shift interrupet switch is not centered to check the throttle throw and that if it is not btwn 2 7/8 and 3 1/8 to replace cable. It just does not make sense to me that the throttle cable could cause the problem - I'm going to go out now and check/test the iterrupter switch. I will report back with results.

 

[Don S]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

Here is a copy and paste from the OEM manual, page 2A-17.

11. If roller or plunger pin is not centered:
a. Ensure adjustable stud is at bottom of slot in shift lever.
b. Check remote control for proper shift cable output [3 in. (76 mm) ? 1/8 in. (3 mm)].
c. If a and b are correct, ensure drive unit shift cable is not crushed or kinked. (If drive
unit shift cable is binding, the shift cutout switch roller or plunger pin will move off
center when shifting ?into? and ?out of? forward and reverse).

 

[SC_Regal]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

I just checked the interrupter switch - there was a little too much travel before the engine cut out, but not bad. I was able to adjust the position of the switch and it is much better.

I was able to isolate the problem: when shifting back into neutral from either direction, the RPM's are staying too high -not allowing the interrupter switch to engage. It looks like I am not getting the last bit of travel from the throttle at the throttle body linkage.

 

[Don S]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

Disconnect the throttle cable from the throttle body and see if the engine rpm's slow down. And don't start adjusting on the throttle body either
If the rpms are staying too high with the cable disconnected, you cold have other things wrong, like an IAC valve, TP Sensor, etc.

 

[SC_Regal]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

Don, do you have a link fot the correct manual for this? (2000 5.0 EFI) I'm having trouble finding one. Thanks

 

[Don S]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/24/24covr1.pdf

 

[SC_Regal]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

Thanks, the link worked but my brain is not - I worked all night and can't find the section that pertains to the throttle adjustment. A mind is a terrible thing to waste.

 

[SC_Regal]

Re: Mercruiser Alpha I GenII, ? upper shift cable problem, expert advice

Problem solved, Thanks.

Throttle linkage was way out of adjustment. There was no pre-tension on the throttle body linkage at neutral, I adjusted the brass stopper out 6 full turns. The engine now comes down to the proper RPM and the shift iterrupter switch works as it should. Keep my fingers crossed, but it was shifting better than when I bought it.

Thanks again