Alpha 1 clattering noise behind prop???

[Fishjustin87]

I just picked up a 25 FT Glasply with a mercruiser 260 and Alpha one outdrive. Running on the muffs there is a slight clattering behind the prop. If I put slight pressure on the prop it gets louder. Also louder at higher RPM. What could be the cause?

 

[Bondo]

Ayuh,..... Is there oil in the drive,..??

I'm guessin' the shift cable is outa adjustment, 'n the dog-clutches are contactin' each other,.......

 

[Fishjustin87]

I do plan to check that. Just wasn't sure if that would cause a clattering sound. There's a receipt from 8/19 for a full reseal of the drive. He said he only had it out about 3 times since then. ( Although he was trying to sell me a boat).

 

[tank1949]

Of my old memory serves me correctly, forward to reverse on an Alpha is about 1/4 of an circle in movement (or less). Pray that wear on linkage is causing it to be out of alignment(not dogs) . While a buddy moves it forward and reverse (at helm) , you should watched the keyway area on your OD for movement and correct or adjust linkage, if you can. Good luck!

 

[Fishjustin87]

Thank you. I appreciate the info.

 

[76SeaRay]

FYI, when in neutral, the dog clutch is idling in between the forward and reverse gear which are being actively driven by the vertical driveshaft and pinion gear. When you shift to forward, the dog clutch moves forward and the teeth on it engage the teeth on the forward gear. The opposite happens when you shift to reverse. The dog clutch is splined to the propshaft and the forward and reverse gears are free spinning on the propshaft. So, as mentioned above, if the shift cable is out of adjustment, the dog clutch may be pushed forward or reverse and the dog clutch teeth may be just hitting the edges of the teeth on the forward or reverse gears giving the rattle noise. Worse case is a broken or broken gear teeth. If you need some pictures, I have my lower unit apart right now....

 

[Fishjustin87]

Got back to it today and is not doing it now. I believe when I pressed the button on the controls to throttle up it did not fully stay in neutral. Took her out on her maiden voyage for about an hour and a half and all seems good.

 

[crazy charlie]

It got better all by itself???? U joints....or if the clattering returns you can just turn up the stereo.Charlie

 

[Scott06]

Of my old memory serves me correctly, forward to reverse on an Alpha is about 1/4 of an circle in movement (or less). Pray that wear on linkage is causing it to be out of alignment(not dogs) . While a buddy moves it forward and reverse (at helm) , you should watched the keyway area on your OD for movement and correct or adjust linkage, if you can. Good luck!

Yeah it is like 90 degrees of rotation. its also easy to bend the bronze shift fork if you jam the drive back in when they are not aligned and in fwd... unfortunately speaking from experince , and yes its about a $100 part...