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1986 Quicksilver Alpha One throttle control problems

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baitbag

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My boat has a 1986 Mercruiser alpha One outdrive with a Quicksilver throttle control. When shifting from neutral into forward, the gas seems to advance too much before the engine shifts. The result is a 'Slamming' into forward gear due to the excessive throttle. Last year a mechanic installed a new shift cable in the outdrive gearbox before the problem arose. I suspect the problem is in the throttle control box and have had no luck in finding an exploded diagram for the throttle controls before I disassemble it. There have been a few occasions when shifting into forward, and advancing the throttle, when the throttle was unable to open fully. I brought the shifter arm back to neutral and then shifted into forward again and the problem was gone. Lastly, when shifting from forward back to reverse and then to neutral when maneuvering up to a dock etc. ,I often have to wiggle the throttle handle and fish around for neutral. It doesn't feel like there is a detent position sometimes when shifting into neutral. Diagrams and/or suggestions appreciated.
 
when it opens, click "mercruiser, then scroll all the way to the right, the last one is "controls
check your messages
 
""Last year a mechanic installed a new shift cable in the outdrive gearbox before the problem arose.""

If you are referring to the short cable that goes to the outdrive then he did not adjust the cables correctly.

Here are my instructions on how to adjust the cables after installing a short cable. Hope this helps........

Trim outdrive up 2 inches from all the way down.
Take keys out of ignition!!!!!!!!!!!
Have a second person stand at the prop.
You, remove the short shift cable from the shift bracket.
After the cable has been removed, push the plastic cable end all the way in and hold in place while prop is being spun C’Clockwise..
Have second person rotate prop counter clock wise until the prop is fully engaged and wont turn anymore. Maintain light effort on shift cable plastic end pushing it to keep forward engaged.

Measure the distance from the center of the brass trunion to the center of the round mounting hole in the plastic end. Adjust trunion to make that distance 6 inches. no more no less! In cases where the shift cable is old but still works well you can adjust this dimension to 5 15/16”. NO MORE.

Put shift control handle in forward FULL throttle position.
Remove the control shift cable from shift bracket at this time.

Install short shift cable back onto bracket at this time.

Take the shift control cable and adjust the trunion so it fits perfectly back into the shift bracket.
Before completely installing it turn the brass trunion 4 complete turns away from the plastic end and reinstall into shift bracket and install the nuts but do not tighten at this time.

Now put shift control handle in the neutral position.
Have second person spin prop, it should spin freely.
Put shift control into the forward detent position at ~ 10:00 position. NO FUTHER.
Have the second person rotate the prop counter clockwise. You should have solid engagement with no ability to continue to turn the prop.

Now shift back into neutral. Prop should spin freely with no clacking or clunking.

Now shift to reverse to the 2:00 o’clock position detent NO FURTHER!!

Have the second person spin the prop clockwise.

If you have positive engagement with no clunking or jumping out of engagement, you are done.

If it does not fully engage into reverse than look at the shift bracket where the short shift cable mounts and there is a slot. Loosen the 7/16 hex that is touching the bracket and move the stud so you are pulling the short cable.

If this all works then tighten all nuts down making sure the cable ends move freely and the nuts are not tight against the shift cable ends. The studs must spin freely inside the cable ends.

Try this and retest in water under load.

Anyway there are tests that would tell you if the cable is bad but to difficult to type out here but in general if you remove the shift control cable from the shift bracket, shift the control handle to full forward/wide open throttle and make a mark on the cable end, now go full reverse and repeat. Measure distance between marks, (2 7/8" to 3 1/8") any more and replace the control cable.
 
In the field we DO NOT repair throttle and shift control boxes, we replace them. The liability is too high.

If the shift control box is malfunctioning Replace it. The chances of it malfunctioning after you take it apart and try to repair it are north of 90%.

When you get the new QuickSilver Gen2 box you will have to replace the control cables too.


Question, Would you put faulty brakes on your vehicle? Repairing a control box is the same thing.
 
FYI

I can fix em................haha

The 1986 vintage are hard to come by and myself and a dozen friends have the same box.....

Did my friends last fall in the boat!!

Not for everyone but then again............that's just me....

Actually I wanted to figure out what caused the push button for neutral start up not to push in, So I took one apart and figured it out many years ago.

Once I learned what the failure was I figured out how to fix it..

I am actually going to seek out a few to keep as spares, rework them and have them on the shelf...




Docksidemarineservices said:
In the field we DO NOT repair throttle and shift control boxes, we replace them. The liability is too high.

If the shift control box is malfunctioning Replace it. The chances of it malfunctioning after you take it apart and try to repair it are north of 90%.

When you get the new QuickSilver Gen2 box you will have to replace the control cables too.


Question, Would you put faulty brakes on your vehicle? Repairing a control box is the same thing.
Click to expand...
 
Chris I am not exactly sure what he meant by outdrive gear box but I think he is referring to the short cable being replaced...Not the shift control box at the helm....
 
kghost said:
Chris I am not exactly sure what he meant by outdrive gear box but I think he is referring to the short cable being replaced...Not the shift control box at the helm....
Click to expand...


This is why I suggested he replace it. It's 30 years old and nothing lasts forever.

"I suspect the problem is in the throttle control box and have had no luck in finding an exploded diagram for the throttle controls before I disassemble it. There have been a few occasions when shifting into forward, and advancing the throttle, when the throttle was unable to open fully. I brought the shifter arm back to neutral and then shifted into forward again and the problem was gone. Lastly, when shifting from forward back to reverse and then to neutral when maneuvering up to a dock etc. ,I often have to wiggle the throttle handle and fish around for neutral. It doesn't feel like there is a detent position sometimes when shifting into neutral. Diagrams and/or suggestions appreciated."
 
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