HELP! Not a Spun Hub

[rcfairchild]

I've had a reoccuring problem of what would be symptomatic of a spun hub. I have replaced hub. Same problem. Marked inner and outter hubs. They matched up. So not a spun hub, Rt? Possible gear problem? The last 5 times i've taken the boat out no problem whatsoever. But when i do have the problem the boat still has forward drive with a little throlte. As soon as i give it any power the engine winds up and no forward drive. The only other information i have noticed is i sometimes have forward drive in neutral. I sometimes can't free spin the prop when shut off in neutral. The problem has happened gone away, come back and gone away again. Would that be a gear problem? If so, why would it go away and come back? I have drained oil and no metal shavings. Has hard click when put in gear. Sounds like its engaugeing just fine. When it runs i have no problems at ALL. PLEASE HELP. LORD have mercey. thanks,

 

[ezeke]

Re: HELP! Not a Spun Hub

If you don't have the coupler back on the shift rod correctly, the clutch dog will not engage fully with the gears. Take a look at the connector/coupler and be sure that the screws are passing through the beveled area of the shift rod sections.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

Thanks i'll do that now. One thing i didn't mention. This problem has always happen after engine had run for an hour or so. thanks again.

 

[tashasdaddy]

Re: HELP! Not a Spun Hub

what motor????

 

[F_R]

Re: HELP! Not a Spun Hub

rc, it would help a lot if you would post the year/model of your motor so we know what we are dealing with. Right now, I am thinking "electric shift" but have no way of confirming that.

 

[ezeke]

Re: HELP! Not a Spun Hub

Curious as to the propeller. How did you replace the hub? It is not a do-it-yourself job and even large dealerships usually send the props out to specialized shops.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

-1996 30hp Evinrude

-I replaced the entire prop

- Ran again. Same problem

-Marked the hub

-ran again, acted up again

-Hub still matched up on new prop.

- puzzled?

 

[ezeke]

Re: HELP! Not a Spun Hub

Your connector/coupler on the shift rod may still be the problem, but it is a different one than the thumbnail that I attached earlier.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

Thanks. that makes more sense than anything anyone has told me so far. Do you think that it sounds like a gear problem at all?

 

[ezeke]

Re: HELP! Not a Spun Hub

If it is, it is serious. I would try everything possible to insure that the gears are engaging fully before tearing down that gearcase. Usually that means putting the gearcase in forward in the normal way and then determining if that is as far as the shift rod can go. You need to adjust all the linkage to maximize the movement at the gearcase.

 

[jtexas]

Re: HELP! Not a Spun Hub

just to be clear on one thing: idles in forward just fine then throttle up the engine revs and the boat don't go...if you back down to idle, it starts pushing the boat again? No grinding of gears? No "CLUNK" going out of gear then "CLUNK" back into gear? No feeling like you hit a stump?

And you ruled out slippery prop 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.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

-Correct-idle in forward drive-fine
-no grinding, no clunk/stump
- problem has occurred 3 of the last 10 trips- not consecutively
-once the problem starts it doesn't "work" again til i take prop off.
-weight loads don't trigger the problem
- I have a new prop on and it has done it with new prop
-I've taken off the prop and put back on everytime its acted up

 

[jtexas]

Re: HELP! Not a Spun Hub

hmmmm......doesn't work until you reinstall prop.........

You said earlier, "...when i do have the problem the boat still has forward drive with a little throttle..." Do you have to move the shifter to neutral and back into gear in order get forward drive? Or have you tried just throttling back without shifting, and the boat starts moving again?

how bout some pics? prop on and prop off.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

honestly, i can't remember.

When i start to throttle up it grabs up to a point and then "slips"
in a split sec it runs up to 4k rpm and i have to cut the throttle back so fast i haven't felt or noticed it reengauging before i get it into N.

If i can get it to do it again i will try that out.

A bit of additional info.

(all in the same trip) First time it happened at 2500 rpm, brought it back down to N. Second time, same thing. Thrid, about 1500 rpm. From then on it was anything beyond slight forward drive would make it "slip". THat's when i thought for sure it was a spun hud. Bought new prop. Did the same thing????

 

[CharlieB]

Re: HELP! Not a Spun Hub

The fact that it is now occuring at progressively lower rpm leads me to think that you are stripping out a spline on one of the shafts.

Engine OFF, pull the spark plug wires off, shift into forward gear and turn the prop, can you turn over the motor?

Listen carefully if there is any clicking, slipping or ratcheting noise anywhere.

Can you drop the gearcase and inspect to spline on the verticle shaft?

Repost with your findings.

 

[rcfairchild]

Re: HELP! Not a Spun Hub

I will test that and post tomorrow. thanks for the input!

 

[rcfairchild]

Re: HELP! Not a Spun Hub

CB i tested the gears..

-in F drive i rotated the prop Clockwise
-no sounds other than what seemed to be air pressure equalizing(fant hiss)
-felt like it grabbed rt away, no grinding, popping, slipping.
-Rotated several times same rusults
-when rotating clockwise i stopped and rotated back counterclk and there was about a quarter rotation play before it caught- not sure if that really meant anything.

I will try and drop the lower unit tonight--never done it before anything i should try and aviod?

 

[ezeke]

Re: HELP! Not a Spun Hub

The clutch dog mates inside the gear and has some freedom so when you turn the propeller in the other direction it it is normal for it to feel loose.

Turning the propeller will not tell you much. Once you have the unit off and can turn the driveshaft clockwise, you can check the gears. Be sure to note the position of the shift rod connector before you disconnect it. A picture would be great.

 

[CharlieB]

Re: HELP! Not a Spun Hub

The fact that you could turn the motor over by turning the prop indicates the gearcase is probably OK. A bad spine should have failed.

One more test just before you drop the gearcase.

Put a suitable block of wood between the prop and the gearcase, shift into forward gear, remove the spark plug, using a socket and wrench try to turn the motor over.

What I am suspecting is rare, but your symtoms are similar to those of a broken crank, it holds but only up to a certain amount of power then it slips.

If you are able to turn the motor over while the prop is blocked then you will know, and we can proceed accordingly. Then drop the gearcase, again block the prop and turn the verticle shaft, determine if that slips or you go into the motor.

 

[Xcusme]

Re: HELP! Not a Spun Hub

What I am suspecting is rare, but your symtoms are similar to those of a broken crank, it holds but only up to a certain amount of power then it slips.

"Broken crank" might be better described as stripped crank shaft splines. If you're lucky, the drive shaft splines are toast and the crank shaft splines are basically still intact.