76 Evinrude 85hp gear case issues please help

[jafitzwater]

1976 85hp evinrude
I'm having a big problem here.
The story;

I purchased the boat with this motor and when I took it out it shifted and ran great propelled the boat to 45mph.

After a handful of times taking it out one day when trying to throttle up the boat wouldn't go fast it felt like it was bogging down.

I changed the gear oil and it was black as night so I assumed that could be the issue. After doing that I tried to shift and spin the prop since it seemed like it wasn't completely engaged and when putting it into gear the forward would slip until I manually pushed the linkage forward then it would engage.

I did the test to see if it could have been the lower end and when removing the plugs and putting in gear by hand then spinning the flywheel it moves the prop. Also when moving the prop when manually doing the shifting it locks the prop from spinning in forward and reverse then freely in neutral.

After I put it all together then adjusted the cables to where it shifts properly I took it to the lake and put it in gear and it still does the same thing!

What is going on??

Please help
Thx

 

[F_R]

Re: 76 Evinrude 85hp gear case issues please help

The first thing you need tot do is determine whether the problem is in the motor, cables, control, or whatever. Disconnect the cables from the motor and see if it will shift manually.

Also, "bogging" or lack of acceleration (once it is in gear) often is caused by sticky spark advance i.e. you move the lever but the timer doesn't advance. Caused by old/congealed/cold lubrication of the timer base.

 

[racerone]

Re: 76 Evinrude 85hp gear case issues please help

Do a compression test on the motor.--Check for spark on all 4 cylinders.----Gas oil mixture is 50:1 on that motor,--------That motor has the " hydraulic assist " powershift lower unit.------It uses oil pressure to do the shifting with less effort for the operator.----It can be shifted when motor is not running but not the best idea.

 

[jafitzwater]

Re: 76 Evinrude 85hp gear case issues please help

The first thing you need tot do is determine whether the problem is in the motor, cables, control, or whatever. Disconnect the cables from the motor and see if it will shift manually.

Also, "bogging" or lack of acceleration (once it is in gear) often is caused by sticky spark advance i.e. you move the lever but the timer doesn't advance. Caused by old/congealed/cold lubrication of the timer base.

I have already manually shifted it and that does work. Where exactly do you mean a sticky timer base? Are you talking about the advance lever that moves with the throttle?

Do a compression test on the motor.--Check for spark on all 4 cylinders.----Gas oil mixture is 50:1 on that motor,--------That motor has the " hydraulic assist " powershift lower unit.------It uses oil pressure to do the shifting with less effort for the operator.----It can be shifted when motor is not running but not the best idea.

The engine is running great the oil mixture is fine. Compression is fine spark is fine.

I'm aware of the Hydro assist however it does seem like when it's in the water I even have wobbling or a rattle down at the prop when trying to go full speed.

 

[jafitzwater]

Re: 76 Evinrude 85hp gear case issues please help

Also just noticed gear oil coming from the water holes above the cavitation plate and around the prop.

Any ideas?

 

[emdsapmgr]

Re: 76 Evinrude 85hp gear case issues please help

Is the leaking oil a caramel color or pitch black color? Caramel color is gear oil, black oil is exhaust residue and is normal on a 2-stroke. If it's the caramel color, you may need to get the gearcase re-sealed. Have a marine dealership do vacuum/pressure tests on the lower unit to determine if it's really leaking-then decide on the repairs needed.