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75 Formula Shift Issue

8

805HD

Regular Contributor
Shift interrupter switch not engaging...

Boat ran just fine first outing, shifted like butter all day.

Second time out shifting issues. Drive will go into gear but won't come out with engine load on it. Shut the engine off, back into neutral, restart, select gear, drops in fine but won't come out. On the trailer I noticed the notch that actuates the arm on the interupter switch barely moves when shifting. The plate with the notch moves freely by hand but barley moves when moving the shifter at the helm.

I adjusted the brass barrel out of curiosity, 10 turns out got the notched plate to move enough to engage the switch but it stayed engaged and only for reverse which I know isn't right. Its just interesting because the boat was shifting fine a week ago and Ive done nothing to it since!

The shifter isn't soft or spongy.
Shift cable is dead on at 5 7/8'' barrel to stud.
Idle set around 600rpm.

Any ideas?
 
805HD said:
Shift interrupter switch not engaging...

Boat ran just fine first outing, shifted like butter all day.

Second time out shifting issues. Drive will go into gear but won't come out with engine load on it. Shut the engine off, back into neutral, restart, select gear, drops in fine but won't come out. On the trailer I noticed the notch that actuates the arm on the interupter switch barely moves when shifting. The plate with the notch moves freely by hand but barley moves when moving the shifter at the helm.

I adjusted the brass barrel out of curiosity, 10 turns out got the notched plate to move enough to engage the switch but it stayed engaged and only for reverse which I know isn't right. Its just interesting because the boat was shifting fine a week ago and Ive done nothing to it since!

The shifter isn't soft or spongy.
Shift cable is dead on at 5 7/8'' barrel to stud.
Idle set around 600rpm.

Any ideas?
Click to expand...

1. On a trailer the interupter may not engage as there is no load on the prop and prop shaft. it has to be confirmed in the water under load

2. if you activate the switch only ( anytime on or off trailer) does the engine stall?
 
kghost said:
1. On a trailer the interupter may not engage as there is no load on the prop and prop shaft. it has to be confirmed in the water under load

2. if you activate the switch only ( anytime on or off trailer) does the engine stall?
Click to expand...
Well damn, thought I found the problem. So without load on the prop even the mechanical mechanism that activates the switch doesn’t work? I’ll get it fired today on the trailer and see if the switch still functions. I just find it hard to believe the switch went out just sitting in the trailer, but crazier things have happened.

Also, glad to see you’re still on here buddy! It’s been a minute!
 
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Yes, its no more than an on/off micro switch. When depressed it shorts Coil - to ground which kills ignition. (When working properly you barely notice this happening.)

With ignition OFF

set meter to ohms. Connect either meter lead to one wire with one lead coming off switch. There typically is a small terminal block where the wires are connect from the swith and engine wire harness

Meter should read a direct short when Switch is depressed (like checking a good fuse Zero ohms) and open (like a blown fuse) when not depressed.

If it does not show short when depressed the switch is bad.
 
kghost said:
Yes, its no more than an on/off micro switch. When depressed it shorts Coil - to ground which kills ignition. (When working properly you barely notice this happening.)

With ignition OFF

set meter to ohms. Connect either meter lead to one wire with one lead coming off switch. There typically is a small terminal block where the wires are connect from the swith and engine wire harness

Meter should read a direct short when Switch is depressed (like checking a good fuse Zero ohms) and open (like a blown fuse) when not depressed.

If it does not show short when depressed the switch is bad.
Click to expand...
I checked the switch, it’s good. I also verified continuity from the switch lead to the coil. Meter beeped from both positive and negative posts of the coil to the switch when the arm with the wheel was depressed…

Was kinda hoping it would have been as simple as just a bad switch..
 
You say all was good one day & goofy next time with absolutely nothing done to the cables. Yes/No?

You also mention 5 7/8". ***This is important, read carefully.***
Early units use 5 7/8" I'm not sure of the exact cut over date but is about where you are at. Later units use 6".
The difference is a long or short slot in the arm for the lower cable stud to mount. Long is about 2" (uses 5 7/8") & short is about 1" (uses 6"). THIS ADJUSTMENT IS CENTER OF BARREL TO CENTER OF STUD.

As cables wear you slowly gain clearance between the moving cable & stationary housing. This creates lost travel action at each bend. You may just have worn cables (controller to shift plate & plate to lower unit).

How old is lower cable? Does it move smoothly & easily?
 
Droid said:
You say all was good one day & goofy next time with absolutely nothing done to the cables. Yes/No?

You also mention 5 7/8". ***This is important, read carefully.***
Early units use 5 7/8" I'm not sure of the exact cut over date but is about where you are at. Later units use 6".
The difference is a long or short slot in the arm for the lower cable stud to mount. Long is about 2" (uses 5 7/8") & short is about 1" (uses 6"). THIS ADJUSTMENT IS CENTER OF BARREL TO CENTER OF STUD.

As cables wear you slowly gain clearance between the moving cable & stationary housing. This creates lost travel action at each bend. You may just have worn cables (controller to shift plate & plate to lower unit).

How old is lower cable? Does it move smoothly & easily?
Click to expand...
Correct, last weekend it was fine sat on the trailer for a week and now it’s goofy. The lower shift cable was just replaced so last weekend was its first time out since replacement. The controls and cables are smooth. No springy, bunchy, dragging resistance at all.

The cable that was put in the boat is,

“Sierra Marine 18-2190 Mercruiser Lower Shift Cable”.

The boat is a 1975. She’s old, things wear/ settle, I understand tolerances vary. When I did the cable I didn’t do an adjustment. I just installed, verified F, N,R and sent it. Perhaps a shift adjustment from scratch is what she needs.

When you take that measurement, whether it’s 5”7/8 or 6” are you measuring with the cable installed on the shift plate or off?
 
shift cable adjustment.

Remove both from bracket.
Shift control to full wide open throttle.
Now push short cable all tbe way in by hand and turn prop C'clockwise to engage clutch dog. Maintain slight positive pressure on ahort cable end and make measuremint from barrel to center of mounting hole in cable end.

Mount short cable to bracket.

Now see how control cable fits. Adjust barrel to fit. Now readjust barrel 3-4 turns towards cable (not cable end).

Not mount control cable.

Now manualy, Engine NOT running.

Bring shift control to neutral. Make sure prop spins freely and no clacking.
Move shift control to forward detent and confirm at prop positive engagemnet. Repeat for reverse.

Who did cable install? How much slack at cable end where set screw is in F shaped part?

How far did you threaded part of shift cable thread into bellhousing? Should be maybe 1-2 threads showing only
 
kghost said:
shift cable adjustment.

Remove both from bracket.
Shift control to full wide open throttle.
Now push short cable all tbe way in by hand and turn prop C'clockwise to engage clutch dog. Maintain slight positive pressure on ahort cable end and make measuremint from barrel to center of mounting hole in cable end.

Mount short cable to bracket.

Now see how control cable fits. Adjust barrel to fit. Now readjust barrel 3-4 turns towards cable (not cable end).

Not mount control cable.

Now manualy, Engine NOT running.

Bring shift control to neutral. Make sure prop spins freely and no clacking.
Move shift control to forward detent and confirm at prop positive engagemnet. Repeat for reverse.

Who did cable install? How much slack at cable end where set screw is in F shaped part?

How far did you threaded part of shift cable thread into bellhousing? Should be maybe 1-2 threads showing only
Click to expand...
I did the install, I apologize but you lost me on the F shaped part. Could you please clarify?

I’m by no means a marine mechanic but I followed a good video on YouTube, a 6 part removal, build and install from an actual Mercruiser mechanic. Not just some guy in his garage. Definitely didn’t make any assumptions or leave anything loose. Did it by the book.

The boat still shifts fine minus the disengagement once in gear. Engine off it shifts fine. The switch is good so something moved or stretched.

As I said before I didn’t do an adjustment because I had smooth movement with positive lock and ratchet on forward and reverse and free spin on neutral. Nothing looks loose. I’m gonna investigate deeper today and I’ll repot back.

Really appreciate the help!
 
805HD said:
I did the install, I apologize but you lost me on the F shaped part. Could you please clarify?

I’m by no means a marine mechanic but I followed a good video on YouTube, a 6 part removal, build and install from an actual Mercruiser mechanic. Not just some guy in his garage. Definitely didn’t make any assumptions or leave anything loose. Did it by the book.

As I said before I didn’t do an adjustment because I had smooth movement with positive lock and ratchet on forward and reverse and free spin on neutral. Nothing looks loose. I’m gonna investigate deeper today and I’ll repot back

Really appreciate the help!
Click to expand...
Send me your phone number

Where are you located? If outside US you will have to call me
 
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MAKE IT QUICK. You are on my time on a Saturday night. i am not on your time.


You have 15 minutes and then I have no idea when or if I will respond
 
"F shaped part" is the part that goes on the end of cable lower end.
Set screw holds it captive. Just snug then back off maybe 1/4 turn. Part must be free to rotate. But nearly no slack or you will loose travel. Then install the safety wire to hold the set screw.

Regarding the 18-2190. That is the "Rear entry" later generation cable. Your boat originally used the forward entry cable.
So I assume either your bell housing was previously "rethreaded" or you did it upon installation.
Best to use a straight tap (special order & a bit pricey) from the front to chase the treads all the way thru then use a tapered tap from the rear.
Too deep/loose & cable may not tighten. Too shallow & cable hex may not go in far enough & you won't be able to adjust in enough travel for reverse.
 
Droid said:
"F shaped part" is the part that goes on the end of cable lower end.
Set screw holds it captive. Just snug then back off maybe 1/4 turn. Part must be free to rotate. But nearly no slack or you will loose travel. Then install the safety wire to hold the set screw.

Regarding the 18-2190. That is the "Rear entry" later generation cable. Your boat originally used the forward entry cable.
So I assume either your bell housing was previously "rethreaded" or you did it upon installation.
Best to use a straight tap (special order & a bit pricey) from the front to chase the treads all the way thru then use a tapered tap from the rear.
Too deep/loose & cable may not tighten. Too shallow & cable hex may not go in far enough & you won't be able to adjust in enough travel for reverse.
Click to expand...
Ohhh okay yes did it exactly as you described snug back of and safety wire it.

Didn’t have an issue with the threads, it was harder getting the damn thing off that it was in so I’m assuming I got really lucky and it was already done because I was not aware of that. You’re saying I used the wrong cable?

Let’s not forget that the boat ran a whole day perfectly. Zero issues with shifting, sat on the trailer for a week and then had issues right off the dock when I couldn’t get it out of reverse.

Something is no doubt out of adjustment but I don’t think I’m dealing with anything catastrophic here.
 
The cable you used is a correct part but only of you or someone prior had rethreaded it as I said above.

So I can only assume the threaded end of the old one taken off & the 18-2190 put on were the same & not opposite design.

Regardless, the entire adjustment procedure needs to be followed.
 
Droid said:
The cable you used is a correct part but only of you or someone prior had rethreaded it as I said above.

So I can only assume the threaded end of the old one taken off & the 18-2190 put on were the same & not opposite design.

Regardless, the entire adjustment procedure needs to be followed.
Click to expand...
Understood. Didn’t have to force or fight anything. I bought the boat as a project. It did run but it was in rough shape. Pulled the engine and went through everything mechanical and electrical. My point is, the boat is very new to me and we’re still in the shake down stages after reassembly..

Gonna follow adjustment procedure to a T tomorrow.

I greatly appreciate the information and guidance. Thank you.
 
Trim outdrive up ~ 2 inches from all the way down. (This puts a slight strain on short shift cable)
Take keys out of ignition!!!!!!!!!!!
Have a second person stand at the prop.
You, remove the short shift cable from the shift bracket. The one that goes to the outdrive.

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 Barrel to the center of the round mounting hole in the plastic end. Adjust Barrel 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. * Older drive systems May have a shorter set distance I believe 5 7/8”.

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

Install Short shift cable back onto shift bracket at this time.

Take the shift control cable and adjust the Barrel so it fits perfectly back into the shift bracket.
Before completely installing it turn the brass Barrel 3-4 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. with no clacking or clunking.

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 detent position 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 end 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. Retest Reverse at detent 2 O'clock.

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

Try this and retest in water under load.
 
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kghost said:
Try this and retest in water under load.
Click to expand...
I followed your instructions exactly, was surprised how much adjustment was needed. Nothing crazy, but definitely needed it. I’m thinking the issue may have been at the upper shift cable. It’s original to the boat as far as I know so I’m sure it’s a bit tired to say the least.

Reverse didn’t want to lock the first go around so that extra adjustment off the reverse lock out was the move.

Time will tell, I know this is a dead horse of a subject. Appreciate the detailed write up.

Thank you.
 
Tests that would tell you if the cable/linkage is bad,

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 at the cable end on the steel threaded tube that cable core runs through, now go full reverse and repeat mark on steel tube again.

Measure distance between marks, (2 7/8" to 3 1/8") anymore and replace the control cable.


You should not need this test because you replaced the cable BUT it may be worth doing to confirm no issues with bell housing linkage or lower unit shift spool.

Short cable measurement test,

Remove short cable from shift bracket, push all the way in and spin prop by hand C’clock wise until full forward is made. After it is in forward gear, with a person holding prop locked in gear you pull lightly until resistance is felt, then make mark 1 on steel threaded steel tube at end of plastic connector.
Next,
Pull cable for reverse, spin prop clockwise, person holds prop in locked in gear.
Push cable lightly until resistance is felt the make mark 2 on threaded steel tube.

Note: This is a touchy/Feely kind of test so you may want to do it a couple times.
Note: locked in gear. Is very important as you are creating resistance on cable core so the only movement will be cable slack or linkage slack.

Measure between marks.

The measurement should be, 1/2 " to 9/16". Anymore, the cable or linkage in bell housing or lower gear case is bad.
 
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kghost said:
Tests that would tell you if the cable/linkage is bad,

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 at the cable end on the steel threaded tube that cable core runs through, now go full reverse and repeat mark on steel tube again.

Measure distance between marks, (2 7/8" to 3 1/8") anymore and replace the control cable.


You should not need this test because you replaced the cable BUT it may be worth doing to confirm no issues with bell housing linkage or lower unit shift spool.

Short cable measurement test,

Remove short cable from shift bracket, push all the way in and spin prop by hand C’clock wise until full forward is made. After it is in forward gear, with a person holding prop locked in gear you pull lightly until resistance is felt, then make mark 1 on steel threaded steel tube at end of plastic connector.
Next,
Pull cable for reverse, spin prop clockwise, person holds prop in locked in gear.
Push cable lightly until resistance is felt the make mark 2 on threaded steel tube.

Note: This is a touchy/Feely kind of test so you may want to do it a couple times.
Note: locked in gear. Is very important as you are creating resistance on cable core so the only movement will be cable slack or linkage slack.

Measure between marks.

The measurement should be, 1/2 " to 9/16". Anymore, the cable or linkage in bell housing or lower gear case is bad.
Click to expand...
how much adjustment is considered normal or within the realm of “normal” off that 7/16 stud? It was about half way center of the slot. I moved it all the way towards port checked gears and called it a day.

Was thinking last night maybe that was supposed to be a little more of a fine tuning situation?
 
The slot adjustment is what it ends up at.

Due to age of boat/outdrive more than likely there are other issues that may be causing more travel required to aquire both Fwd and Rev.

A new cable change on a all in spec shift system works usually with no slot adjustment when in the middle of the slot.

I posted how to check cables and there to many unknowns about the shape of all the other components.

These are the problems with a 50 yr old boat. Things DONT work like they did when new.

The shift spool used up to early '80's wore and caused shift engagement issues.
Then they did away with the bronze and made it all Steel. that proplem got solved. So unless your drive has been updated there is no way to tell from here
 
kghost said:
The slot adjustment is what it ends up at.

Due to age of boat/outdrive more than likely there are other issues that may be causing more travel required to aquire both Fwd and Rev.

A new cable change on a all in spec shift system works usually with no slot adjustment when in the middle of the slot.

I posted how to check cables and there to many unknowns about the shape of all the other components.

These are the problems with a 50 yr old boat. Things DONT work like they did when new.

The shift spool used up to early '80's wore and caused shift engagement issues.
Then they did away with the bronze and made it all Steel. that proplem got solved. So unless your drive has been updated there is no way to tell from here
Click to expand...
I hear ya.

Dipping the boat tomorrow morning, I still find the whole thing weird. This isn’t my first rodeo and that boat was shifting in and out of gear smooth as butter one weekend, and not so much the other.

Shift adjustment procedure definitely required more adjustment than I would have suspected but things work on the dry so here we are.

Hopefully tomorrow goes well..
 
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