Knocking in outdrive in gear only

[choochooharley]

Hello all,

Ok today I was getting ready to take my 1975 24' Reinell with a Mercruiser 888 out to slay some fishies and I decided for some reason to tun it with the muffs on. Well when I did I put it in gear and heard some knocking from the outdrive. It did it in Forward and Reverse but not nuteral. It also appeared to me that the outdrive was vibrating a bit. I just bought the boat and this is the first time I was going to take it out. I should preface this with saying a few week back not knowing the kids moved the ladder over the outdrive I ran it with the muffs on and put it in gear and hit the ladder and dinged up the prop pretty good. I have not replaced the prop yet but will now I am wondering what else I am going to have to replace anyone have any ideas what the knocking noise could be?

Thanks,

 

[dubs283]

Re: Knocking in outdrive in gear only

could be a number of things causing the knocking

i would be suspect of the "ladder bash" you described - if it was hard enough to damage the prop, it could have done some internal damage

when running on the muffs and in gear, check the propshaft for straightness/wobble

keep in mind that when the engine is running, most of the internal components of the drive are turning as well - upper and lower gearsets are spinning, even in neutral

have you drained the lube to check for metal??

 

[choochooharley]

Re: Knocking in outdrive in gear only

I am heading out the door right now to check the lube after i check the prop shaft. I thought I saw some wobble with the prop on but couldnt tell so I have pulle the prop and I am going to put it in gear with out the prop to see if i see any wooble or if the noise is improved or worsened or what. I know the inner gears and such turn in nuteral as well thats why my thinking is its the gears for forward and reverse themselves but im not that familar with the set.

 

[zbnutcase]

Re: Knocking in outdrive in gear only

A broken gear tooth in the lower can cause knocking in gear, if it was in upper it would do it in neutral also.

 

[sethjon]

Re: Knocking in outdrive in gear only

Hello all,

Ok today I was getting ready to take my 1975 24' Reinell with a Mercruiser 888 out to slay some fishies and I decided for some reason to tun it with the muffs on. Well when I did I put it in gear and heard some knocking from the outdrive. It did it in Forward and Reverse but not nuteral. It also appeared to me that the outdrive was vibrating a bit. I just bought the boat and this is the first time I was going to take it out. I should preface this with saying a few week back not knowing the kids moved the ladder over the outdrive I ran it with the muffs on and put it in gear and hit the ladder and dinged up the prop pretty good. I have not replaced the prop yet but will now I am wondering what else I am going to have to replace anyone have any ideas what the knocking noise could be?

Thanks,

The bottom line is nobody can tell what the problem is until you pull the OD.

 

[choochooharley]

Re: Knocking in outdrive in gear only

ok the lube looks clean and when I pulled the prop off the noise was no longer there. Could this be becuase the prop is causing the noise or is it because there is no weight on the prop shaft?

 

[dubs283]

Re: Knocking in outdrive in gear only

Could this be becuase the prop is causing the noise or is it because there is no weight on the prop shaft?

sure, but being that there is a knocking noise with the prop on in gear, you still have an issue

you can try a new prop - its possible its just the prop

was the propshaft straight - no wobble in gear??

 

[choochooharley]

Re: Knocking in outdrive in gear only

To my eyes there was no wobble and i do not have the tool to check to be accurate but i could not see one with the naked eye either that or it was so minute that it was unnoticable

 

[Don S]

Re: Knocking in outdrive in gear only

If the shaft looks ok, have the prop checked by your local prop shop. The hub may be damaged, or a blade bent allowing it to hit the trim tab anode, or the lower unit housing.

 

[choochooharley]

Re: Knocking in outdrive in gear only

Thanks I ordered a new prop and hub kit. I will also have this one checked to see if It can be repaired as a spare. I hope this fixes it I will post and let ecery1 know if it was the prop or if I need to spend more money.

 

[choochooharley]

Re: Knocking in outdrive in gear only

well the new prop didnt fix the problem I suspect a bent prop shaft or broken gears. I am leaning toward the prop shaft though since it does it in both forward and reverse. Does anyone know if a SE 106 lower unit will bolt right up the the mercruiser top end? you can get a brand new lower unit for 695. For me to do the work myself on the lower unit would be just about as much because id have to buy 250 in tools and i suspect it wouldnt be much cheaper at 70 and hour to have some one repair it.

 

[gamarines2]

Re: Knocking in outdrive in gear only

Here's a thought from a novice, maybe he was running his outdrive on his muffs in the trailered (risen) position, causing a terrible and unhealthy strain on his u-joints....it wouldn't be the first time a new owner thought it was ok to run the motor in this condition on muffs.

If so, this could be the knocking (and it continues in the lowered position) then my guess is u-joints.

 

[gamarines2]

Re: Knocking in outdrive in gear only

But then again, after having re-read the thread, u-joints would be bangin' all the time, not just in gear....

Going back to sleep now.