wrong lower unit oil in a hydro elec

txbandit44

Petty Officer 2nd Class
Joined
May 11, 2008
Messages
182
OK I suspect that the last guy to own this motor didnt use type c oil. What do I need to do to change it? Should I just drain and refill or some sort of flush.

The problem that I am having is that if I can get it into forward it pops out of gear. I have a spare set of solonoids I was going to drop in since the wires on this unit are spliced inside the case. But I still think the cause might be the wrong oil.


What do yall think.
 

bigpoppakdog

Chief Petty Officer
Joined
Jul 9, 2008
Messages
437
Re: wrong lower unit oil in a hydro elec

heard different views on the oil issue. Some will say you have to use the special oil, while others have said they have it with the regular oil and have had no problems. So....???? Mine would pop out of gear due to a bad control box. I switched that out to a toggle switch setup. Much better. Have to wait for others to give their input on the solenoid and possible clutch dog issue.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: wrong lower unit oil in a hydro elec

hydro-electric, requires Premium Blend Type "C" oil, just drain well, and install the type "C".

Hydro Electric Shift)
(J. Reeves)

The shifting setup of the lower unit is what's called a "Hydro Electric Shift", which is quite complex consisting of voltage being applied to solenoids in the lower unit which in turn change oil passages via a oil pump that supplies various pressure on a spring loaded shifter dog. The wires leading to the lower unit (at the powerhead) are "Green" and "Blue". The engine must be running or cranking over in order to shift out of forward gear.

You CAN NOT use HI VIS lube in that lower unit. You MUST USE what OMC calls "Premium Blend" lube, commonly called "Type C". (A thinner lube)

In neutral, you need 12v to the "Green" wire.
In reverse, you need 12v to both wires, the "Green" one and the "Blue" one.
In forward, there should be no voltage to either wire. (The spring loaded shifter dog forces the unit into forward gear)

To check the lower unit for proper shifting to make sure you have no trouble there, remove the spark plugs to avoid problems and to allow a higher cranking speed.

This next step eliminates the actual shift switch in case problems may exist there.... Disconnect the blue & green wires at the knife connectors (the rubber insulated boots) leading to the lower unit at the powerhead, then using jumpers, take voltage direct from the starter solenoid to apply voltage to the "Green" wire for neutral, then both wires 'Green" & "Blue" for reverse (Remember the engine must be cranking over in order to shift).
With no voltage applied, the unit should be in forward. No need for a ground jumper... the lower unit's already grounded. You may crank the engine with the key switch or by energizing the starter solenoid with a jumper wire.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: wrong lower unit oil in a hydro elec

OK I suspect that the last guy to own this motor didnt use type c oil. What do I need to do to change it? Should I just drain and refill or some sort of flush.

The problem that I am having is that if I can get it into forward it pops out of gear. I have a spare set of solonoids I was going to drop in since the wires on this unit are spliced inside the case. But I still think the cause might be the wrong oil.


What do yall think.

Since it defaults to forward gear, try disconnecting the blue and green wires going down to the lower unit. That will put it in forward gear, taking the entire electrical system out of the picture. If it pops out, there is a problem in the lower unit, not the electrical system. I suppose it could be the oil if it is way too thick. Just drain it out and refill.

It is unusual for those to have worn clutch dogs, the "normal" reason for jumping out of gear. But the piston that moves the dog is a very close fit in the bore that it slides in, and metal chips and other debris can make it stick. It might not be sliding all the way into forward. If that's the case, no cure except for total tear-down.
 

shawpdx1

Petty Officer 1st Class
Joined
Apr 29, 2009
Messages
294
Re: wrong lower unit oil in a hydro elec

Everyone says type "c" oil who makes type c what is it? probably a stupid question but went to Napa and no one new what it was need to change out my oil thanks
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,385
Re: wrong lower unit oil in a hydro elec

Everyone says type "c" oil who makes type c what is it? probably a stupid question but went to Napa and no one new what it was need to change out my oil thanks
Could be an OMC dealer thing. Most likely expensive but worth every penny if it solves the issue.
 

jay_merrill

Vice Admiral
Joined
Dec 5, 2007
Messages
5,653
Re: wrong lower unit oil in a hydro elec

You definately need to use Type C. While NAPA stocks some OMC outboard parts, I'm not surprised that the folks there didn't know what you wer talking about. Go to your local OMC/BRP dealer and ask for "Premium Blend" gearcase oil - its the current equivalent of Type C oil.

The wires that F R is talking about run down into the midesection on the port side of the motor, inside of the cowl. You will see a pair of wires with black rubber boots on them. Slide the boots off of the connectors that are under them. These pieces are connected in a "handshake" fashion. Rotate them into a V and you will then see how they come apart. Do not pull on them - they won't come apart unless properly positioned and you will just risk breaking the wires. While the upper portion wouldn't be all that big a deal to fix, the wires that go down into the midsection are part of a specially constructed wiring harness that is NLA - you really, really, really do no want to break it!
 

jumanjii1

Cadet
Joined
Jul 11, 2008
Messages
17
Re: wrong lower unit oil in a hydro elec

iboat.com sells the Type "C" gear oil you seek. $6.79 a quart.

I have the same engine with the hydro electric shift and am about to start it for the first time. Been working on the engine since last summer when I acquired it and a boat on the cheap. Well the engine was a mess and wouldn't turn over. The starter solenoid was wired wrong, the carbs were clogged, the ignition was shot including the rectifier, the amplifier assembly, the clipper assembly and the coil assembly. Replaced it all plus the spark plug wires and points and fuel lines. I might as well gotten a new engine:mad:
And don't forget to change out the water pump. What about a new prop, I'm throwing one in too.
In any event, the compression was good and the engine was clean and now it turns over and I have spark.

And that hydro electric shift better work. I know the prop turns in the forward direction:D

Good Luck
 

shawpdx1

Petty Officer 1st Class
Joined
Apr 29, 2009
Messages
294
Re: wrong lower unit oil in a hydro elec

yeah just got mine running yesterday runs real strong. but if its going to Happen its going to happen out there!! (laugh) only concern is with the ear muffs on not much water was weaping out of the hole. ran it for 15 min did not get hot or at least light did not come on. motor did not feel to hot either. checked the drive went right into forward and into reverse. was thinking about backing it down into the water today and run it on the trailer since chinook fishing is done. let it run for awhile maybe spin it close to dock.
also missing the trim unit I never notice that until yesterday. wonder if I need it or if I could pirate one off a another motor like a johnson or something interchageable to accept onto a 1969 55hp evinrude
 

txbandit44

Petty Officer 2nd Class
Joined
May 11, 2008
Messages
182
Re: wrong lower unit oil in a hydro elec

pulled the solenoids and drained the fluid right of the batg I know they used good ol 90w oil gotta love that sulfur smell. Anyway cleaned all the sift parts and flushed it out with diesel fuel. Reassy'd and runs like a scalded dog. Best $100 deal I ever made
 
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