Prop Buster
Cadet
- Joined
- Sep 10, 2007
- Messages
- 22
Just learned something and wanted to share:
I have had numerous constant overheating problems the past two years .
I have a 305 GMC in a 1995 2400SCR Maxum with a Alpha One lower unit.
I took everything apart and cleaned,replaced whatever was needed.
Talking to the mechanics that regularly work on these engines outdrives, they showed me something that is appearing more frequently (especialy with older boats/lower units.)
They found that the cast aluminum that is directly underneath the impellar starts to pit and disintergrate to the point that it will pass air undrneath the gasket (at higher RPM'S),.
To inexpensively repair this delima, they build up the edge of pitted part with Marine Epoxy and then level it off. Before putting back the gakset on top they run a bead of "Form-a- gasket" or "marine silcone" along the edge to futher solidify the seal.
The tell tale sign is overheating at higher rpm's.
I have actually seen this with two lower units dissassembled and I did check mine and thankfully my cast aluminum was not disentergrating.
It is an inexpensive repair to a nuisance problem. The other altenative is to replace the lower unit housing which runs around $1500.00
Just thought I'd throw that out there
Good luck to all.........
Prop Buster
I have had numerous constant overheating problems the past two years .
I have a 305 GMC in a 1995 2400SCR Maxum with a Alpha One lower unit.
I took everything apart and cleaned,replaced whatever was needed.
Talking to the mechanics that regularly work on these engines outdrives, they showed me something that is appearing more frequently (especialy with older boats/lower units.)
They found that the cast aluminum that is directly underneath the impellar starts to pit and disintergrate to the point that it will pass air undrneath the gasket (at higher RPM'S),.
To inexpensively repair this delima, they build up the edge of pitted part with Marine Epoxy and then level it off. Before putting back the gakset on top they run a bead of "Form-a- gasket" or "marine silcone" along the edge to futher solidify the seal.
The tell tale sign is overheating at higher rpm's.
I have actually seen this with two lower units dissassembled and I did check mine and thankfully my cast aluminum was not disentergrating.
It is an inexpensive repair to a nuisance problem. The other altenative is to replace the lower unit housing which runs around $1500.00
Just thought I'd throw that out there
Good luck to all.........
Prop Buster
