115 hp won't go backwards, plus other questions

[nitsuj]

Hi all, this is my first post, I hope someone can help. I know this topic has been hit, but I haven't seen any one answer, and I have a twist I haven't seen mentioned yet. The motor is a 1971 115, hydro electric shift. When I first start it up, everything is fine. But after a few minutes, reverse won't work. I still have neutral, but pulling the lever back makes the boat go forward. If I pull the lever the whole way back, I go full speed ahead! It makes trailering interesting! I understand that it could be the solenoid, or the switch in the control housing. But why the first few minutes of normal operation? And how can I check it out of water? If it turns out to be the solenoid, how tough a job is it? I'm a motorcycle mechanic for a living with an extensive Snap-On collection, so I'm capable. Is the motor worth the trouble? Anyone ever converted one of these to non-electric shift? Should I just be looking for a newer boat? I admit, I'm somewhat attached to this one, but if it's just going to be junk, even when it is running, I'd just as soon chuck the whole thing. I should also remember that it's attached to a 1970 17 1/2 Glastron Semi V hull, and it will be used for weekend river running. Thanks for any words of advice.

 

[nitsuj]

Re: 115 hp won't go backwards, plus other questions

By the way, I forgot to ask, one solution that was given to me was to drain the oil out of the bottom end, replace it with kerosene, run it for a few minutes, then refill with oil. Any merit to this?

 

[nitsuj]

Re: 115 hp won't go backwards, plus other questions

Should I just sink it?

 

[trumpetbucks]

Re: 115 hp won't go backwards, plus other questions

Nitsuj:<br /><br />I'm answering this only to bump your post up and to mention some names. These guys probably do a search for their name and might be able to help you out. There has to be someone else out there who can help as well.<br /><br />Joe Reeves<br />Outboard Jim<br />DHadley<br /><br />Don't answer back. If people see too many replies to your topic, they'll assume someone has already helped you.<br /><br />Best of luck! This sounds like a doozy of a problem.

 

[Joe Reeves]

Re: 115 hp won't go backwards, plus other questions

I could swear that I answered this question previously, and that it was double posted. Thinking that I answered the other post, I checked for it but it doesn't exist... not anymore anyway. Perhaps it was on a different website. At any rate.......<br /><br />Seeing as how the engine does operate as it should initially when you start it, but has the shift act up right shortly after that, makes me wonder if you have the wrong lubricant in that lower unit. That unit demands "OMC Premium Blend" also know as "Type C". You cannot use the lubricant that the mechanical units use which is "HiVis" due to its heavier viscosity.<br /><br />And you did check and fill the lower unit from the bottom drain hole until it flows out the top oil level hole?<br /><br />Hopefully the following information may give you some insight on that problem.<br /><br />(Hydro Electric Shift)<br /><br />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.<br /> <br />You CAN NOT use HI VIS lube in that lower unit. You MUST USE what OMC calls "Preminum Blend" lube, commonly called "Type C". (A thinner lube) <br /><br />In neutral, you need 12v to the "Green" wire. <br />In reverse, you need 12v to both wires, the "Green" one and the "Blue" one. <br />In forward, there should be no voltage to either wire. (The spring loaded shifter dog forces the unit into forward gear) <br /><br />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. <br /><br />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).<br /> <br />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.

 

[nitsuj]

Re: 115 hp won't go backwards, plus other questions

Wow, excellent advice! Thank you! I know I have the type c lube in there, but I'll check the rest of the things you mentioned. One more question, does the kerosene trick have any merit? The logic was that maybe there was enough sludge build up that it was making the type c thicker. Is it even worth a try?