270 Shift Travel (Throw) Specs

[rman]

Does anyone know how much shift cable travel (throw) an early 270 outdrive should require? I haven't been able to find the specifications on it anywhere.

For 15+ years we've lived with what seams to be a constant tweaking of the shift linkage to keep it to where it will consistently always shift in both forward and reverse. I replaced the shift cable with a new 33C Supreme cable I think it was which helped some and replaced the Morse MT-2 with a Morse MT-3 single lever shifter which also helped but it still seams like there still isn't enough travel for what the outdrive needs. The MT-3 is supposed to have 2 3/4" travel as opposed to the 2 1/2" of thee MT-2 from what I could find.

But it seams like the outdrive would like 2 7/8" or 3" to be safe.

There's no sharp bends in the cable and the MT-2 was original equipment on my 1971 34' Chriscraft Houseboat with this setup and most of the time it shifts be even with the new controls and cable I could manually still move the shift lever on the outdrive a bit more each way if I disconnect the cable.

I've been thinking of just rigging up a pivot plate with a shorter cable running to it that would allow me to extend the throw more because swinging a 40' overall length houseboat into a slip with 50' between the rows of slips is a bit unnervering when you're not 100% sure that it's going to shift each time.

 

[boatdoc55]

I've never had any problem with anyone's 33c cables but have had to short of throw boxes. The Morse boxes have always worked well for me. Remember it is RPM's that make it engage deeper, the shift shoe is just sending the cone clutch in the right direction for your needed gear and RPM's take over from there.

 

[sandkicker]

I've had problems with my circa 1969 Morse single lever setup on my 250 and then 280 drives in that the shift engage point @ the shift lever was vague.
a) Cause #1... the stamped "gear sector" in the head that links the throttle to the shift mechanism is worn. Ther is no fix for this except a new head.
b)Cause #2...Slop in the link at the drive itself. I added two thin small S/S washers, on on each side of the Volvo shift link (arm) to the cable so that there was no side to side (radial) slop in the shift linkage. You have to be very careful that the O/D of the washers you select do not prevent the shift arm from travelling to its full range when in forward. On my drives at least, there is only about 1/16" clearance between the end of the arm and the casing when in forward.
c) Cause #3.... same as #2, except at the head.

The problem can be diagnosed by observing how the shift linkage in the drive moves when you shift from F to N to R. The cable should be adjusted per the shop manual before starting doing this test. Disconnecting the shift cable from the drive and then seeing how much you can move the cable in/out will help you determine if the slop is in the drive end or in the head end.

Some shift heads have two holes you can choose from to control the length of throw of the shift cable.

With the cable adjusted per the manual (in neutral),disconnect the shift cable from the drive, shift the head into F (see cable extend). By hand, shift the drive @ the drive into F (shift arm down) and see if the fitting on the shift cable will line up with the shift arm.

 

[RicardoMarine]

Remember it is RPM's that make it engage deeper, the shift shoe is just sending the cone clutch in the right direction for your needed gear and RPM's take over from there.

Agree.
As the sliding sleeve begins to feel the friction against the rotating gear cup, it can't help but further engage. Torque takes over, and further engagement occurs. That's just the nature of the cone clutch gear engagement.

However, if the gear oil has become contaminated, it may cause issues. Likewise with metallic debris embedded in the sliding sleeve surface.
A typicall issues is that house boats rarely get pulled for routine maintenance.


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Here's a very simple procedure for adjusting the early AQ series drive 33C shift cable:

NOTE: the shift components... (shift lever handle, 33C cable, gear yoke, vertical linkage, etc) should allow for some cable "over-travel" for either gear engagement. This is very normal. Divide any over-travel equally.


Start with the vertical linkage piece (SEQ # 18 below) disconnected from the gear yoke (SEQ #2 below).
Position the eccentric piston in absolute Nuetral (horizontal).
You'll feel the detent wanting to maintain Nuetral.

Make a full shift lever move into FWD gear. The cable will extend, pushing the gear yoke AFT.

Now put the eccentric piston in the FWD gear selection. I.E...... LH prop will be full CW.... RH prop will be full CCW.

Align the vertical linkage and see which direction that the clevis may need to be adjusted.
See above note again!

Make certain that the gear yoke does not bottom out against the Intermediate housing. If it does, shorten the cable adjustment some.

Now move the eccentric piston into a REV gear selection.
Move the shift handle to REV position. The cable will retract, pulling the gear yoke FWD, as well as pushing FWD on the coupling rod (SEQ #3).

Again, align the vertical linkage and see which direction that the clevis may need to be adjusted.
See above note again!

Make certain that the gear yoke does not bottom out against the Intermediate housing. If it does, lengthen the cable adjustment some.


When the shift lever is placed in absolute Nuetral, and with the eccentric piston in Nuetral....., the vertical linkage piece should align with no required further adjustment.


IMO, it's all about begining with absolute nuetral.

 

[sandkicker]

It should be noted that the shift cable via SEQ 39 and 68 can be connected to EITHER arm of the gear yoke #2, depending on if the cable enters the drive on the port or starboard side of the lower unit. As shown, it enters on port and the cable end fitting #39 faces right, while on many other drives it will enter on starboard and the cable fitting #39 will face left as it attaches to the right hand arm of the gear yoke #2.
The washers I suggested to remove slop are added, one on each side of the gear yoke arm on the pin of #39... Use a new S/S cotter pin.

 

[rman]

It should be noted that the shift cable via SEQ 39 and 68 can be connected to EITHER arm of the gear yoke #2, depending on if the cable enters the drive on the port or starboard side of the lower unit. As shown, it enters on port and the cable end fitting #39 faces right, while on many other drives it will enter on starboard and the cable fitting #39 will face left as it attaches to the right hand arm of the gear yoke #2.
The washers I suggested to remove slop are added, one on each side of the gear yoke arm on the pin of #39... Use a new S/S cotter pin.

Thanks guys. I'll double check the washers but I think I've already added on one on each side from what I can remember and can just get the cotter pin back through it. But maybe it was just to the shift cable and not to the shift linkage so I'll have to see.

The shift arm on the new Morse MT3 does have a long and short throw and I have it setup to use the long throw which did help.

I've noticed how close it comes to the bottom before and it's always been a horrible design I thought. Especially now with Zebra mussels that can get up under the cover. I typically clean it out a couple times a year at least.

 

[sandkicker]

re: "it's always been a horrible design I thought. Especially now with Zebra mussels that can get up under the cover. "

You're only saying that because you've never owned a MERC Alpha One!

Re: Zebra mussels...try smearing a thick film of PTFE trailer hitch grease on the bottom and a bit on the arm itself.

 

[RicardoMarine]

The washers I suggested to remove slop are added, one on each side of the gear yoke arm on the pin of #39... Use a new S/S cotter pin.

Yes, I also always add SS washers if none exist.

re: "it's always been a horrible design I thought. Especially now with Zebra mussels that can get up under the cover. "

1.... You're only saying that because you've never owned a MERC Alpha One!

2.... Re: Zebra mussels...try smearing a thick film of PTFE trailer hitch grease on the bottom and a bit on the arm itself.

1.... Amen.... consider yourself fortunate.

2.... I hang a menu inside of this area:

Today's special....... "Fresh Zebra Mussels served with rice pilaf, garlic bread and salad........ $9.95 "

It works!


.

 

[boatdoc55]

Yes, I also always add SS washers if none exist.




1.... Amen.... consider yourself fortunate.

2.... I hang a menu inside of this area:

Today's special....... "Fresh Zebra Mussels served with rice pilaf, garlic bread and salad........ $9.95 "

It works!


.

#1 Keeps all us marine mechanics busy and beans on the table!! Fricken Mercruiser clutch dog systems, what a joke!

 

[RicardoMarine]

#1 Keeps all us marine mechanics busy and beans on the table!! Fricken Mercruiser clutch dog systems, what a joke!

I agree, and I'll add..... unless you've experienced the V/P cone clutch drives..... you just won't know what you've been missing.

And BTW... the good stuff is the AQ series main suspension fork/pivot tube geometry of the mid 90's.... not the SX or DP-S gimbal suspension drives.


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