Ducktwin Gas Tank Pinhole Leaks

[treeguy]

Recently I purchased what I thought was a pretty decent Evinrude Ducktwin. When I started going through it, I noticed that there was quite a bit of white-crusty material in the gas tank. I filled the tank with some gas and sloshed it around and left it for an evening. The next day I noticed a pool of gas under the motor. I thought it might be a carb issue. While going through the carb, I noticed the float was toast so I replaced it. With the tank off the motor, I decided to give it a thorough cleaning. While doing this, I noticed 2 small pinhole leaks on the bottom-front portion of the tank.

I’ve restored several 3hp Evinrudes and have never seen a pinhole leak in a single tank. Of course my first experience with an Evinrude 3hp gas tank pinhole had to be a Ducktwin (arghhh). I could replace the Ducktwin tank with an extra Lightwin tank I have, but I’d rather not do that. Has anyone else here experienced pinholes in Evinrude/Johnson 3hp tanks before? I’ve never seal coated the interior of a gas tank before, any suggestions? I’ve read a little on Kreem, PO-15, and Red Kote and it seems most experienced folks prefer Red Kote, any thoughts? Thank you for any help.

[frankr]

I’ve used Kreem with good results. Your experience may vary.

[lyks2tinkr]

I highly recommend the Damon Redkote. The advantage of it is that it stays flexible. I have done many tanks both steel and aluminum with great results. Follow the instructions on the can and you’ll be golden.
It’s not cheap but you’ll get many tanks sealed from that quart.

[lindy46]

Por15 works well. A little expensive and an involved procedure but my 1947 Sportsman tank has no leaks after 4 years.

[sydinnj]

I have sealed many tanks, actually also used it to coat a tank that just did not want to come clean, actually a Johnson A. I would clean it and think that it was good, put it back on and run it and the carb would clog up again. put the coating inside the tank back around 1980 and it is still holding. I have used several brands and all have worked for me.

[The Boat House]

[treeguy]

I finally got around to completing my Ducktwin project. Finding a nice replacement Ducktwin tank with original paint and a good decal would be pretty difficult where I live. I have an extra Lightwin tank that would have worked, but I like original motors and it would have been difficult to paint the Lightwin tank to recreate a Ducktwin tank with patina.I used JB Tank Weld to seal up all of the pinholes (and larger holes) in the tank and two coats of Red Kote to seal the interior of the tank. After about four days of sitting with fuel in the tank, there are absolutely no leaks.

As for the rest of the motor, I cleaned off the years of grime, cleaned the carb, replaced the cork float that was shot, replaced the coils, cleaned and set the points, replaced the impeller, and changed the lower unit oil. Two pulls of the rope and it started and runs well. Just in time for duck season! I’ll take some photos later tonight.

[treeguy]

Here are a couple of photos of the subject motor.

[sydinnj]

very nice, one day I I have one to get going and I even have an old duck boat to put it on.

[lindy46]

Nice looking motor.

[Author]

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