1976 to 1987 lower unit swap

[meanerdeaner]

i have a 1976 70hp johnson model 70el76d and hope someone can tell me if a 1987 70hp johnson model j70tlcur lower unit will fit and if so do i need to change anything.thanks for any help

 

[racerone]

Should work.

 

[meanerdeaner]

Should work.

ok thanks alot

 

[meanerdeaner]

ok i bought it put it on and the motor wont turn over.the prop wouldnt turn either way and woudnt shift.i took i back off and without moving the shift rod prop spins free both ways as it should in neutral and the motor turns over fine.so i looked at the drive shaft and the 87 has a long driveshaft and gearcase.is their anything i can do to make this work

 

[jimmbo]

The 76 is a Hydro-Mechanical Shift and the 87 would be a straight Mechanical Shift.
I don't recall there being a short shaft 70hp in 76.
You are saying that apart, the engine rotates, and the Propshaft turns, but together, neither will turn?
Can the driveshaft be turned, when the lower unit is off?

 

[racerone]

I thought the switch from HYDRO-ELECTRIC occurred during the 1975 model year.-----Are measurements of the driveshaft length different ?-----

 

[meanerdeaner]

The 76 is a Hydro-Mechanical Shift and the 87 would be a straight Mechanical Shift.
I don't recall there being a short shaft 70hp in 76.
You are saying that apart, the engine rotates, and the Propshaft turns, but together, neither will turn?
Can the driveshaft be turned, when the lower unit is off?

the 76 is a long shaft and yes the drive shaft turns when not on the motor.neither turns when together

 

[meanerdeaner]

I thought the switch from HYDRO-ELECTRIC occurred during the 1975 model year.-----Are measurements of the driveshaft length different ?-----

yes the 87 is 21 1/4in to the case and the 76 is 21 to th case

 

[racerone]

Measure the length of the driveshafts from bolting surface to the top.----Pictures of the lower units.----Does the 76 lower unit shift to forward with an UP motion of the shift rod ?

 

[jimmbo]

I thought the switch from HYDRO-ELECTRIC occurred during the 1975 model year.-----Are measurements of the driveshaft length different ?-----

72 was the last year for Hydro-Electric, replaced by the Hydro-Mechanical in 73

 

[meanerdeaner]

Measure the length of the driveshafts from bolting surface to the top.----Pictures of the lower units.----Does the 76 lower unit shift to forward with an UP motion of the shift rod ?

it does.thats where i measured from.the shift rod from the 87 was longer also and the place i bought it from said to switch with 76 shift rod which i did

 

[racerone]

I meant that hydro-mechanical ( powershift II ) was changed / deleted during the 1975 model year.

 

[jimmbo]

I thought the switch to unassisted shift was around 77 for the 70hp and 79 for the V4s

 

[racerone]

Part way through the 1975 model year for the 70 HP

 

[meanerdeaner]

Measure the length of the driveshafts from bolting surface to the top.----Pictures of the lower units.----Does the 76 lower unit shift to forward with an UP motion of the shift rod ?

i remeasured and the 87 is 21 11/16 and the 76 is 21 1/16.i put the 87 unit on without connecting the shift rod and it turned over really hard and i couldnt turn the prop.then i loosened the bolts up about a 1/4in and the prop turned free.but i didnt want to crank it with the bolts loose

 

[jimmbo]

5/8" is a lot. I'm surprised that you were able to to bolt it on. Doing so jammed the Crankshaft upwards, and the Driveshaft downwards pushing on the Gears and Propshaft. Likely caused Damage to the Water Pump, and put a hell of a Load on the Crankcase Sealing Rings and their Grooves on the Crankshaft, wouldn't be surprised if there was Damage to the Upper Bearing Carrier as well

 

[racerone]

Doubt there is any damage to the upper bearing on this 3 cylinder motor.-----And the 3 cylinder does not have sealing rings on the crankshaft.

 

[meanerdeaner]

Doubt there is any damage to the upper bearing on this 3 cylinder motor.-----And the 3 cylinder does not have sealing rings on the crankshaft.

so it sounds like the 600 i spent on the lower unit and new water pump was a complete waste of money.can i swap the drive shafts out

 

[jimmbo]

Doubt there is any damage to the upper bearing on this 3 cylinder motor.-----And the 3 cylinder does not have sealing rings on the crankshaft.

You're right, for some reason I got stuck on the V4s

 

[meanerdeaner]

is there a complete lower unit rebuild kit for the 70el76d i cant find one.