Fixing plastic engine cowls using fiberglass and resin

LonnieKlein

Member
Hi everyone, it's been sometime since I've posted here. I have an 04 etec 90hp. With cracked side covers. These replacement parts are outrageous and rare to find. I was wondering if anyone has tried to repair a plastic engine cowl using fiberglass and resin on the interior?
Will it hold up? I figured it would bond.
THANKS
 
Lonnie,
My answer is; yes, no, maybe. A lot depends on the type of plastic used in the covers. Some plastics are notorious for being unable to bond to. My suggestion would be to visit a good local autobody shop and ask them what they use for repairing plastic auto parts. Also try searching you-tube for videos in repairing plastic parts on autos. (I suspect you'd get more results than a similar search on outboard motor cowlings.

That said, I have successfully glued and bonded to some plastics with "standard" epoxy resins. Just repaired a friends broken transducer housing.

Yet, I have a rotomolded kayak which required repair by adding melted plastic into the damaged area, much the same as adding filler rod under the heat of an acetylene torch.

If you find that epoxy will in fact adhere, I'd suggest drilling a hole at the ends of the cracks to prevent further cracking along the same fault line.
 
From what I have gathered, this is a known issue with several years of this model. Something to do with the composite of the plastic. I think I will try it as there are several long cracks and a couple missing small pieces. Thanks for your input
 
Are you talking about cracks all the through the cowling or something more along the lines of spiderwebbing? Low surface energy (LSE) plastics are tough to bond without some sort of priming. Flame treating, corona, and chemical primers are typically employed. Some will say simply lenabrasion is good for LSE plastics but I don?t agree

If not LSE, you can use any number of Epoxy or Acrylic polyurethane and even some hot Melts to fix.

I would look on the inside of the motor cover and look for any markings that may tell you what kind of plastic it is. The marking may look similar to what you would find on a bottle of ketchup. Let me know what you find

As I as also suggested, bring the cover to an auto body shop and they have techniques that can tell you the type of plastic and how to repair.

Mark
 
I did a quick search and wow, that is very common and those are expensive to replace. Not fiberglass. I?d look up on an etec users group and find the official best way to fix. Sucks.
 
I just fixed my 75 hp etec with JB weld tiny piece of fiberglass cloth on the inside i didn't take any pictures but two months its still holding. i Cleaned with acetone first but whatever acetone touches etches the plastic so use caution. The lower cowling screw hole broke off thats what i actually replaced.
 
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