4 blade over torque outdrive

[shaw520]

1990 280 SR w twin merc 305's alpha 1.
I've had this boat 2weeks, .. 860 hrs on each motor. On Sunday I was on plane at 3200 rpm when the port side outdrive let's loose, Upon disassembly i discovered the upper pinion gear set on port side oitdrive stripped out. My local marina says it's from over torque (too large a prop), ... my opinion tends to differ. What I found in the upper pinion gear housing leads me to belive that this was caused by low oil level. Marina says that a low oil condition would have fried the upper bearing before shearing the pinion gear, upper bearing seamed fine and did not look heat stressed (blue discolored). All your opinion are welcome.

 

[GA_Boater]

What size is this large prop?

 

[shaw520]

IDK,...only found a 437 stamped in the side of one prop,... they are 4 blade measuring 14" dia

 

[Scott Danforth]

find a different marina.

the alpha drive is good for 300hp (well more than the 305's would ever produce).

what caused the failure - who knows. however it wasnt from your prop or the torque produced from the 305's

 

[shaw520]

No Title

Notice no oil coating on gears or on metal shavings

 

[Scott Danforth]

its toast. since short of spending many times more than the outdrive would cost to determine cause and fault, your most likely going to have to spring for a new upper at a minimum - recommended complete outdrive. Iboats sells SEI units that will bolt on in under an hour and have you back on the water.

 

[GA_Boater]

Check the lube in the lower unit. Actually change it and look for metal in the drained oil. When you get the replacement upper, you don't want it destroyed by old junk from the lower.

 

[harleyman1975]

$1500 for a complete SEI with 3 year no questions asked warranty.

 

[shaw520]

Thank you ..all good advise 4 sure, I have a spare outdrive for this boat, already bolted her on,.. fingers crossed.

 

[shaw520]

Back in the water this morning,... everything seem ok, brought both engines up to 4900 rpms with just a bit more left on the stick (didnt want to bring it over 4900),.. so I dont think Im over propped.
....On another note, this outdrive makes a slight whirling noise,(compared to the Starboard side), Its not an alarming sounds, maybe just newer gear set. ??

 

[Scott Danforth]

check the fluid level.

 

[shaw520]

check the fluid level.

Boat would have to come back out for that,.. one of the downfalls of the Gen 1,... 32' X 10'.6 is alot to haul out !