Bent and cracked cavitation plate 70HP Ev

[gyoung]

Hello Everyone,

I have a 70HP, long shaft, 1985 Evinrude in mint condition, till recently!

The other day I hit a block of wood or something similar. The prop must have jambed it up against the cavitation plate on the port side of the leg.

It bent the prop a little but did more damage to the cav plate which is bent up about 3/4 of an inch at the outside trailing corner. There is a 2" long crack where the plate joins the vertical face of the leg. The circular trim plate is also bent up on the port side.

Could anyone tell me how to best repair this? Can the cav plate be straightened and the crack welded? If it can does anything have to be disassembled to avoid heat damage from welding?

I'm running in salt water. Can the repair be left till the boat is hauled this fall? The damage doesn't seem to affect the performance.

Any advice would be really appreciated.

Thanks,

Glen..

 

[tashasdaddy]

Re: Bent and cracked cavitation plate 70HP Ev

check the lower for water intrusion. if no water you should be fine for the rest of the season. a pro welder will have to assess it when hauled. you may have to disassemble to weld. may be cheaper to find a donor case.

 

[gyoung]

Re: Bent and cracked cavitation plate 70HP Ev

Thanks Tashasdaddy,

I'll check for water in the LU and get it assessed later if none.

GY

 

[wbeaton]

Re: Bent and cracked cavitation plate 70HP Ev

If the anti-cavitation plate damage doesn't effect performance then I'm not sure I'd even bother getting it fixed. The prop for sure, but not the plate unless I just couldn't bear the look of it. It can be fixed. Probably easiest to remove the lower unit and take it to a marina to fix during the off season. Also a great time to change the impeller.

 

[5150abf]

Re: Bent and cracked cavitation plate 70HP Ev

I am an aluminum TIG welder by trade (20 years) and can tell you from experience be VERY careful who you let weld this part.
Welding cast aluminum is really tricky, I have rebuilt a skeg and a bunch of my props before and the cast is really easy to get porosity in, it is bubbles in the metal that make the repair weak and you get 1 shot at it, if you get alot of porosity you have to grind it out and start over which makes alot of heat which can crack the casting, it can get really ugly in a hurry.
I would almost bet too that what they would charge you would almost cover a new casting.
Be careful too trying to bend it back,chances are you will just break it the rest of the way off, cast is really grainy and doen't like to bend.
If it doesn't affect your perfomance I would just let it be,maybe put some JB weld on it and sand it down just to get rid of the crack, hit it with some paint and noone will know.

 

[gyoung]

Re: Bent and cracked cavitation plate 70HP Ev

Thanks for the replies tashasdaddy, 5150abf and wbeaton.
I appreciate your advice. I will check that there is no water getting into the gearcase and then decide what to do when I haul in October.
It really hurts to see a perfectly mint motor damaged like that, and I hope it can be repaired for a reasonable cost.

GY

 

[tashasdaddy]

Re: Bent and cracked cavitation plate 70HP Ev

as i said, may be best to find a donor lower, and rebuild it, with your parts.