Volvo Penta AQ series 290 water inlet casting - permanent fix

[Scott Danforth]

Volvo casting 854031 as used on the 290, 280, DPA, etc is a known weak link on the AQ series drives

try as I might, I never had one last more than 3 years and that is even with epoxy coating the new ones.

they just dissolve in brine and last about 5 years in fresh water.

so I think I found a permanent fix for mine





The old one has 40 hours of run time or about 15 months and was pulled last January when I pulled the motor. you can see the pitting starting in a bunch of locations and the casting has a bunch of oxidation blisters under the remaining paint. the epoxy paint was POR15 with the POR15 hardnose paint.

the new one is 316L stainless, laser cut, tig welded and tonight I will hit the interior edges with the die grinder and clean up the exterior.

something else may corrode on the drive now, however this wont be it.

would have machined a billet unit, however the laser and tig were much faster.

 

[Maclin]

Nice fab work. Are you worried about any galvanic interaction?

 

[Scott Danforth]

Not really. The rubber gasket will isolate it. However the stainless H frame is already a large piece of stainless attached to the outdrive.

 

[PatinIdaho]

Nice work!. Bet you could almost make a living off making and selling them or at least some extra boat bucks. You have the hard part done.

 

[HorizonblueDK]

There is still an electrical connection through the screws, so galvanic corrosion can occur. But yes, there is a huge stainless steel bracket for the hydraulic rams on this outdrive, so this inlet won't be the only stainless part. I believe I have seen this inlet, new from Volvo, in plastic, instead of aluminium ?!. I suspect that some of the reason for the corrosion, is that there is a weak connection between the inlet and the rest of the outdrive, because of the rubber gasket. The aluminium inlet is painted, and therefor hardly any connection through the screws.