Engine Shaft Knock - looking for mechanical help!

[TryinHarder]

Hi guys, hoping somebody can help me out. Im on vacation at a lake rental house (of course!) but fortunately the owner of the rental house is letting me use his nice air conditioned shop to repair my 07 Merc 6hp short shaft 4S.

The engine has a knock or bang inside the shaft above the lower unit that knocks against the walls of the shaft even at idle in neutral. It is intermittent but definetly goes up in frequency when the throttle is increased or the motor is in gear. I flushed out the lower unit and found a few serious metal shavings but i am having a hard time getting the backside of the shaft housing off the motor assembly (below the powerhead). i have not found a smoking gun...

in looking at the service manual (i have a PDF version i bought online today for $8, but cant print) it would suggest removing the powerhead to get at the shift linkage. Well before i do that i thought i would get a second opinion. Closest mechanic (Lake Palestine TX) is two weeks behind in work, so i am on my own excepting the great shop and tools.

Any and all help is welcome! :?

Thank you in advance

 

[cajuncook1]

Hi guys, hoping somebody can help me out. Im on vacation at a lake rental house (of course!) but fortunately the owner of the rental house is letting me use his nice air conditioned shop to repair my 07 Merc 6hp short shaft 4S.

The engine has a knock or bang inside the shaft above the lower unit that knocks against the walls of the shaft even at idle in neutral. It is intermittent but definetly goes up in frequency when the throttle is increased or the motor is in gear. I flushed out the lower unit and found a few serious metal shavings but i am having a hard time getting the backside of the shaft housing off the motor assembly (below the powerhead). i have not found a smoking gun...

in looking at the service manual (i have a PDF version i bought online today for $8, but cant print) it would suggest removing the powerhead to get at the shift linkage. Well before i do that i thought i would get a second opinion. Closest mechanic (Lake Palestine TX) is two weeks behind in work, so i am on my own excepting the great shop and tools.

Any and all help is welcome! :?

Thank you in advance

I have not worked on Mercury's( I'm a JohnnyRude dude), but it sounds like you may have a problems with your drive shaft. The drive shaft will spin even though it is neutral. The drive shaft is connected to a pinion gear in the gearcase that engages the forward or reverse gears when you use the shift lever to cause the clutch dog to interface with the forward or reverse gears.

Some fine and small metal shaving is not uncommon with a lot of usage, but you stated serious metal shaving.....not a good sign [-o<

Sorry not familiar with your motor to tell you how to drop the lower unit, but look at this link and maybe you can find a condense manual close to your year and model.

https://www.tinboats.net/forum/viewtopic.php?f=4&t=14047

Good luck my friend!!!

cajuncook1

 

[TryinHarder]

canjuncook1 thanks for the reply. I guess the driveshaft was knocking cause the gears were all torn up. I got the lower unit all tore down and found all three gears were chewed up. I'm waiting on the local Merc dealer to get the parts overnighted so i can get some fishing out of this week. At least the dock held a dinner's worth of crappie yesterday!

 

[cajuncook1]

canjuncook1 thanks for the reply. I guess the driveshaft was knocking cause the gears were all torn up. I got the lower unit all tore down and found all three gears were chewed up. I'm waiting on the local Merc dealer to get the parts overnighted so i can get some fishing out of this week. At least the dock held a dinner's worth of crappie yesterday!

Sorry about your gearcase!!!

But fried crappie!!!!! :mrgreen:

Good luck and fortune!

cajuncook1