Twin DF 300 Corrosion Issues

[CATMAN]

Have "08" 300's - Have had to replace both trim tilt assembly's in "09" after assembly corroded where SS pin runs through the lower part of assembly.
Corrosion was so bad the o-rings blew out within a month of each other on each engine.
Now I'm seeing corrosion starting all over again in the same locations , in addition to about 1/8" deep marble size indentations in the lower unit above the prop shaft.
This boat is on a lift & out of the water, I'm lucky to get out 5-6 times a year, what is causing this corrosion & how do I stop it?

[mitch]

Not sure but sounds like it may be a rigging problem are there any earths straight on to your hull .

is the hull ali

Are all the earth wires still on your leg ?

[CATMAN]

worse than i thought

There is 1 wire from trim/tilt to anode on bottom of transom bracket , bracket is mounted onto a fiberglass transom.
boat sits on carpeted wood runners , the motor zincs & the transom zincs have never pitted or needed replaceing.
There is some sort of galvanic reaction coming from somewhere , i suspected the SS pin was reacting with the aluminum housing of the trim tilt bracket ???
But the new marble size pits starting in the lower unit are baffling me also.

[CATMAN]

Wash down

Longest boat has been in water was 1 week @ a time twice a year on vacation , also I always flush & rinse down.
Maybe I'd be better off leaving it sit in the water & let the barnacles grow on it!

[CATMAN]

1st pair of Trim/Tilt assemblys

This is what the 1st pair looked like after 165 hrs ,

[JUST-IN-TIME]

looks like the bonding wires are bad and the ground wires on motor are bad

[CATMAN]

Grounds

JUST IN TIME ! Will add xtra grounds with heavier wire

[mitch]

That is serious corrosion .

There is something that is really not right as it seems to be earthing back through the tilt pumps .

But them engines should be still under warranty get Suzuki to have a look at them or who ever rigged it up because they have done something really wrong .

[JUST-IN-TIME]

yes sounds like the riggers who set it up missed a bonding wire

[boxster964]

This is the same engine I have i have very little of this but I was wondering if you could help with a question about smis gauges? I have them but suzuki says it should show temp but dealer said it doesnt so expensive gauges that tell me nothing no engine temp oil pressure or water pressure.
Thank you