Prop not staying engaged

[moontraveler1984]

was on the water last night cruising along at wot and all of a sudden the prop disengaged! when I slowed it down and tried to get going again, it was jerking like it was completely engaging. At first I thought it was the ball gears, but when I pulled the boat out, they were fine. What could be causing this problem? 1977 V-Sonic with OMC ford 302.

 

[moontraveler1984]

Re: Prop not staying engaged

Nobody has any suggestions?

 

[chiefalen]

Re: Prop not staying engaged

You have a spun prop? Check that first. You have a pin in that one pin snap?

Did it over heat when it happened? If yes than, maybe the water pump shaft stripped. I hope thats what it is.

If it did overheat and the water pump shaft did not strip you will have to pull the water pump to check. G-d fobid your in the same boat as me right now coupler might have stripped.

If it did not over heat, maybe the clutch dog, i said maybe.

Ok on the trailer, put in in gear turn the prop. does it turn in gear? Does both ball gears turn? If yes it's the coupler for sure.

Post the results we will go from there.

 

[gcboat]

Re: Prop not staying engaged

OMC drives are notorious for eating gears if not properly adjusted. Are you having a difficult time shifthing from neutral to forward or reverse? It should move very easily - if not then here is a good post for you to read.
Actually it's a good post for anyone with an OMC lower unit:http://www.hastings.org/~stuart/cobra/

 

[supercab78]

Re: Prop not staying engaged

Like "chiefalan" said the spline that the impeller rides on may have stripped or rusted. The splines we are talking about look like a small axle shaft on a RWD car.You can't see them until you until you split the lower unit from upper gear case. I have had to replace the two shafts in the upper gear case twice. The splines seen to rust out after about 17 years. Did you have a normal working reverse? If so your splines may be ok. Let us know how things are going.

 

[chiefalen]

Re: Prop not staying engaged

Gc it's a stringer not a corbra.

 

[gcboat]

Re: Prop not staying engaged

Damn - you're right !! My bad for not reading the whole post. But ya' gotta' admit I tried.

 

[bruceb58]

Re: Prop not staying engaged

If it did not over heat, maybe the clutch dog

Are we sure this isn't an electric shift model? The mechanical shifts started in 78.

 

[chiefalen]

Re: Prop not staying engaged

Bruce i don't think it would matter ether way. Still got the ball gears, still got the water pump shaft.

But i hope it's a snapped pin, spun prop something easy.

Test would still be the same turn the prop when in gear and if both ball gears move its the coupler.

If the ball gears don't move its the shaft.

 

[moontraveler1984]

Re: Prop not staying engaged

I know the ball gears are intact, and it didnt over heat. Like I said i was running at wide open throttle, and all of a sudden it was like it shifted out of gear, I didnt spin a prop, because I could idle at about 1200 rpm and and it would engage enough to get us back to the dock. Reverse works fine too. Once I got the rpms above 1500 or so it was cluncking in and out of gear like it couldnt make up its mind whether it should be engaged in gear or not. Someone at marktwain.com said there is a spring hub that might have gone bad, I am going to check that and all the electrical connections when I get a chance. Any ideas on what kind of oil i need to put in the upper and lower units I figure I should go ahead and change all of that while I am at it. Let me know if anyone has any more ideas, and I will keep everyone posted with what I find on teardown.

 

[bruceb58]

Re: Prop not staying engaged

You need type C oil and that may be your problem if you changed the oil and used the wrong oil.

If not the oil, you may have a shift spring problem. The end of the spring has a little turn to it. They can be broken off, especially if you shift your drive at elevated RPMs. Shifting at high idle RPMs will kill your electric shift OMC springs.

 

[chiefalen]

Re: Prop not staying engaged

In my first reply i mentioned the clutch dog. I hope it's not that.

You last reply you went into greater detail ,that you had reverse and it didn't overheat.

You have a good stream of water coming out the trunions? Called a tattle-tale stream. If yes than water pump in outdrive is good.

Good luck1

 

[moontraveler1984]

Re: Prop not staying engaged

If the water pump in the outboard wasn't functioning properly, wouldnt the engine over heat too? I havent changed the oil since I bought the boat... so I am not sure what type of oil is in there, but I was told it was always serviced by a dealer. Like I said it will open the top of the outboard tonight and take a look at things up there.

 

[bruceb58]

Re: Prop not staying engaged

In my first reply i mentioned the clutch dog. I hope it's not that.

This will NOT have a clutch dog!!!! Its a 1977 electric shift!

 

[moontraveler1984]

Re: Prop not staying engaged

Well finally got the chance to get out and tinker a little bit. This is what I have ruled, tell me what you guys have in mind. The oil in the outboard definetely needs changed. I checked to make sure all the electrical connections were connected and they were. the ground wire going from the outboard to the engine was good and connected as were the wires running through the transom. I cant find my voltmeter so I still have to check voltages. I engaged the clutch and tried turning the prop, the prop will turn freely clockwise facing the prop from the back of the boat, but when I try to turn it counter clockwise it wont turn. I also got in and greased all the fittings while i was at it. One other question, can I use 90W-80 gear oil instead of the Type "C" oil, I have read a few things and really dont understand whats the difference between these oils, I guess someone needs to enlighten me. Also, is there any chance that something electrical could have gone out around the dash and throttle, are there any fuses, relays that should be checked too? Tell me what you guys think.

 

[moontraveler1984]

Re: Prop not staying engaged

bump

 

[bruceb58]

Re: Prop not staying engaged

One other question, can I use 90W-80 gear oil instead of the Type "C" oil, I have read a few things and really dont understand whats the difference between these oils, I guess someone needs to enlighten me. Also, is there any chance that something electrical could have gone out around the dash and throttle, are there any fuses, relays that should be checked too? Tell me what you guys think.

You have to use type "C" oil.

A bad switch or resistance in wiring can cause a low voltage situation with not enough current to drive the magnets in the drive. That is why you need to measyre the voltage. You need to measure the voltage while everything is hooked up(ie the magnet being driven)

 

[supercab78]

Re: Prop not staying engaged

I was told by a OMC mech 20 years ago it was ok to use reg i/o oil in everything EXCEPT the lower unit. The lower needs type C because of the electric shift. There should be jackknife connections near the back of engine (inside of boat) that one disconnects in the steps to remove outdrive. Find those (one is for forward and one is reverse) and run a 12 volt jumper from batt. to that lead and test drive it. BE CAREFUL of where you are bacause it will start in gear this way. It BYPASSES the nuetral safty switch. My money is still on the shafts in the intermedite housing. I just had a thought is the v-sonic the boat brand or does your boat some kind of OMC V- drive, as in an exotic shaft drive sysrem?

 

[moontraveler1984]

Re: Prop not staying engaged

I believe the V-Sonic is the boat brand... cant say I have seen one like mine out there, but from what I hear the OMC stern drive setup is not one of the best.

 

[supercab78]

Re: Prop not staying engaged

V-Sonic is boat name so info we've been giving you applies. Yes alot of people dislike them. You can't go to your local marine and get parts that are in stock for them. Not to many shops like to work on them either from what I understand. The type Coil must be used in the electric shift outdrive lower unit.