HELP! Not a Spun Hub

[dimock44]

Re: HELP! Not a Spun Hub

Only one thing causes those symptoms (to my knowledge): cavitation. Or ventilation. Two things.

Possibilities that come to mind:
- something is blocking the flow of water through the prop blades. A bit of vetegation, an external irregularity on the gearcase, damaged prop, something like that.
- something caught in the diffuser ring allows exhaust gas to bleed back on to the blades.
- somehow pulling surface air into the blades.[/quote]

I think jtexas might be on to something. My toon will do that in rough water at times and more so if I don't trim it all the way down. The prop will slip at different Rpm's and in different water conditions. You haven't said what your boat is or did I miss it. I also had a flat bottom ski boat that would get light in the back when cornering. It had a skeg about 5 feet from the stern and in hard full speed turns with the boat trying to slide sideways I think the skeg would throw up some turbulence and cause the prop to slip. It really drove the tach into orbit. Just a thought. Keep us posted.

 

[CharlieB]

Re: HELP! Not a Spun Hub

lol
dimock made a very good point, I've seen lots of toons cavitate on turns.

We never asked what motor it is, the poster finally told us in his 3d post that it is a 30 hp 'Rude

I'm surprised we never asked what boat is this nor did we ask the mounting position of the A/V plate relative to the bottom of the hull.

Sometimes I feel like Homer often says, "D'oh!" (while smacking myself in the head)

 

[dimock44]

Re: HELP! Not a Spun Hub

lol
dimock made a very good point, I've seen lots of toons cavitate on turns.

We never asked what motor it is, the poster finally told us in his 3d post that it is a 30 hp 'Rude

I'm surprised we never asked what boat is this nor did we ask the mounting position of the A/V plate relative to the bottom of the hull.

Sometimes I feel like Homer often says, "D'oh!" (while smacking myself in the head)

Hey ChalieB, mine does it while going straight also. Since his is intermittent it sure would help to see the bottom of his hull and the back of the boat.

I do the Homer thing so often I get headaches .

 

[iwombat]

Re: HELP! Not a Spun Hub

For that matter, we didn't ask if the boat was still tied to the dock, or stuck on the beach.

You can't think of everything.

 

[jtexas]

Re: HELP! Not a Spun Hub

my thinking was, I'm wasn't convinced the motor is jumping out of gear. Reading about the symptoms again, it sounds more like maybe it is, I'm just still holding out some hope.

First time I ever caught a branch on my L/U, I mean just a little twig hung up on the A/V plate, I thought the prop was spun for sure. Earlier this spring I was easing through a shallow gravel bottom creek, motor off but not fully up, picked up two tiny pieces of gravel in the diffuser ring. Didn't manifest until I moved back out into the lake & got exactly the same symptom.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

Thanks you all for the help. I am trying all suggestion but the Tornado last night slowed me down a day but i still have a boat to work on so thats good.

Boat. 1996 Lowe 16ft Aluminum v-hull w/1996 30hp Evinrude

Symtom NoN-Triggers
1. Couldn't get boat to Cav. in very hard tight turn, rough water or trimmed.
2. Weight in boat doesn't seem to have any affect.
3. Happened w/new & used prop. and hubs on both still matched after "slip"

Symptom Possible triggers
1. Has only happened after engine very warm(could be coincidence)
2. Never happened before hit soft mud (first time happened on 3rd trip after Mud)-elimanated spun hub.
3. I do recall lots of weeds and moss in the water at the end of last year.

When it "slips" I have NEVER heard any type of clunk or noise to indicate that it popped out to gear.

Never found any shaving in oil. which i changed after every incident.

I'm going to go down the list of suggestions and try to see what i can find out and post results and pictures.

If i can post any other information that could be helpful please let me know and thanks again for all the advice. greatly appreciated and on other suggestions i just bought the repair bible!!! LOL

 

[rcfairchild]

Re: HELP! Not a Spun Hub

Question? If it were the crank could it work just fine for hours of use after first symtom under different weight levels, Out of the hole over and over again with no "slipage"? To suddenly act up a week later after being ran for an hour? I will do what was suggested to test the crank this evening and post results. thanks.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

After learning a bit more about the inner workings i have better questions.


1. rope caught in prop last year- couldn't start engine-acted like dead battery.

Q: Why would a rope in prop not allow engine to turn over if it wasn't in gear?

2. I have forward drive and then when i throttle up it spins out.

Q: If it is in gear with forward drive then slips out of gear wouldn't it make a noise or have a "stump" action?

3. If purposed idea of broken crank is the problem

Q: would a broken crank promblem become worse and worse? Happen under a high load stress and enventually wear down the crank to a point it would slip all the time or at least not work properlly some of the time?

4. i have the boat in neutral and rise the idol slightly to warm the engine and the boat wants to go forward.

Q: would that indicate that the clutch dog is not disengauging properlly and mean that the shift linkage is the problem?

 

[jtexas]

Re: HELP! Not a Spun Hub

Q.1
That's just wierd. A rope in the prop will kill a running engine when you put it in gear. Don't ask me how I know.

Q.2
It's conceivable that the motor can jump out of gear without you noticing a noise. It wouldn't go out and back into gear (as in, a spun hub) without a noticeable jolt.

Q.3 and 4
All those parts (clutch dog, gearset, crankshaft/driveshaft splines) are metal-on-metal; they don't "slip" without making noise, I would thing a lot of noise (or else I'm about to learn something new ). Prop hub is the only thing that can do that.

Q.4
Lot of times, the first sign of clutch dogs starting to wear down is that "I just hit a stump!" feeling.

You may have noticed the prop spins with the engine running in neutral on the muffs - it's because of the gear oil churning around in there; you can stop it with your hand, although I used a piece of scrap lumber. The weight of the boat is supposed to stop it in the water.

 

[Xcusme]

Re: HELP! Not a Spun Hub

Waiting for the test results to come in....

A couple of things came to mind. He didn't mention if this is a remote setup, I'll assume it is. Could the shift linkage be so mis-adjusted that the dog is engaging forward just enough to turn prop shaft until a slight load causes it to dis-engauge without much ,if any, common thump? Dropping the remote shift cable and shifting manually is a possible fix to ID the problem, and or checking the shift rod length dimension.

I had a 6hp that had stripped crank splines that had exactly the same symptoms. It would sometimes bind the drive shaft in the crank and allow some forward movement until the load on the junction got so great and then would slip, without any noticeable noise as a in a bad dog.

It will be interesting to find out what's going on with this one.....

 

[rcfairchild]

Re: HELP! Not a Spun Hub

-Ran boat 4 hours on Sat. - no act up. Minor 1/2 sec power loss as i was powering down after running full Throttle for 5 mins) no RPM hike or noise assocatiation.
-Ran boat 3 hours on Sunday. No act up. Minor "slip" again just a split second of what felt like the prop not grabbing the water but this time it was out of the hole. Again no RPM hike or noise associtated.

Pulled prop and marked hubs before and after each trip-- all matched up.

Comments on suggestions:

The forward movement in N is more than bearing drag or oil circulation I think because it pushes the boat a great deal.

??Since the rope was around the prop and wouldn't allow me to turn the engine over in N. Wouldn't that indicate that is was not disengaging into N.??


Seems like we keep coming back to several possiblities

1. Shift linkage
2. Clutch dog

Maybe even;

3. broken crank shaft
4. Ventilation/cavation

What should i do next to eliminate any of the possiblities?

Are there any test i should try? what am i Missing?


My next step was going to be dropping the lower unit. I have purchased the repair guide and i.d. the procedure but not the skill to locate the shift link pin under the lower Carb. I have attached pictures of what i believe to be the link but i could use all the help i can get. thank ya'll for all the help thus far.

 

[ezeke]

Re: HELP! Not a Spun Hub

Your shift rod connector should be hiding in the area of the red circle.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

THanks ezeke, You're the picture master!. I looked at that but thought it had to be something else because it doesn't seem to be in line with the upper unit's shifter.


Question. Do i have too or should i drain oil to remove the lower unit?

 

[ezeke]

Re: HELP! Not a Spun Hub

No need to. If you want to lighten the work load, take the prop off.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

I've attached a pic of what i believe is the SHIFT ROD CONNECTOR. The manual i purchased is not helping. I was told it covered all Evinrudes from 92-01 but i'm not seeing my HP engine and don't see how that can be. 90% of it is correct for all models but things like the the shift rod connector are NOT. Anyone have a pdf verison for a 30 hp Evinrude 1996. I will be glad to send you what i have in return.(519 pg PDF Evinrude repair guide 92-'01) 37 mb.

-in pic. which bolt should turn. bottom or top....both. Which direction?

- is it ok to use wd-40 to loosen bolts

- besides the 5 bolts that hold the lower unit on and the shift rod connector is there anything else that is going to keep the unit from dropping.

 

[ottertail]

Re: HELP! Not a Spun Hub

At this point and from reading all the posts I would suspect that the clutch dog and forward gear are worn. I would suggest pulling the bearing carrier and taking a look. This engine does not have a history of a broken crank or spline issues. I have also never seen a broken crank act this way. It has all (from what I read here) the characteristics of fwd gear and clutch dog waer. at the rpm the clutch dog slides up the worn lugs on the fwd gear and it dissengages its self, that is why the engine revs so high so fast. if it was cav/vent it would vibrate and you usually can hear it in the engine besides the rpm increase. It is possible for these lower units to come out of gear with out a clunk, when the rpms are high and the engines is screaming you will not hear any gear case noise on shut down either.