Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 04-10-2014, 03:07   #1
Registered User
 
ErikFinn's Avatar

Join Date: Feb 2011
Location: Malaysia, Thailand
Boat: Beneteau Oceanis 430
Posts: 832
How to weld/glue/fix cracked outboard engine plastic fuel tank?

I bought a used dinghy with a 5 year old 5HP Mercury 2-stroke outboard. There is a 1 cm (1/3 inch) crack at the fuel hose connection in the bottom causing the tank to leak from there. I don't know the full name of the material, but its the original plastic fuel tank. New one sells for around Malaysian Ringgit 500 (includes cap) or about 150 USD, which I think is a bit steep.
So my question is: is there an easy way to fix this? Some special glue/putty or welding maybe?

Cheers,
Erik
__________________

__________________
ErikFinn is offline   Reply With Quote
Old 04-10-2014, 03:41   #2
Marine Service Provider
 
Emmalina's Avatar

Join Date: Jan 2012
Location: Thailand
Boat: Herreshoff Caribbean 50
Posts: 482
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

Go see the Yamaha man behind KFC in Kuah sure he will have something for a lot less.. Or even Farid at the mecury place
__________________

__________________
Steve .. It was the last one that did this !
Emmalina is offline   Reply With Quote
Old 04-10-2014, 03:55   #3
Registered User
 
ErikFinn's Avatar

Join Date: Feb 2011
Location: Malaysia, Thailand
Boat: Beneteau Oceanis 430
Posts: 832
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

Quote:
Originally Posted by Emmalina View Post
Go see the Yamaha man behind KFC in Kuah sure he will have something for a lot less.. Or even Farid at the mecury place
Thanks Emmalina, "Farid at the Mercury place" is also in Kuah, Langkawi, right?

I'm in Penang at the moment.
__________________
ErikFinn is offline   Reply With Quote
Old 04-10-2014, 15:16   #4
cruiser

Join Date: Feb 2008
Location: North Charleston, SC
Boat: Camano Troll
Posts: 4,669
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

Quote:
Originally Posted by ErikFinn View Post
I bought a used dinghy with a 5 year old 5HP Mercury 2-stroke outboard. There is a 1 cm (1/3 inch) crack at the fuel hose connection in the bottom causing the tank to leak from there. I don't know the full name of the material, but its the original plastic fuel tank. New one sells for around Malaysian Ringgit 500 (includes cap) or about 150 USD, which I think is a bit steep.
So my question is: is there an easy way to fix this? Some special glue/putty or welding maybe?

Cheers,
Erik
I don't believe there is an effective DIY way to fix a cracked plastic fuel tank.

You shouldn't need a Mercury branded fuel tank, just one with the correct fittings or one you can install your fittings on.

You might be able to find a used tank from a motor that no longer works.
__________________
rwidman is offline   Reply With Quote
Old 04-10-2014, 15:27   #5
Registered User
 
nimblemotors's Avatar

Join Date: Apr 2011
Location: Sacramento, California
Boat: Solar 40ft Cat :)
Posts: 1,557
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

What kind of plastic is it? That makes all the difference.
If it is HDPE or LDPE, you can 'weld' the cracks to seal them up.
__________________
JackB
MiniMPPT Solar Controller
nimblemotors is offline   Reply With Quote
Old 04-10-2014, 15:32   #6
Registered User
 
MBWhite's Avatar

Join Date: Apr 2012
Location: Illinois
Boat: Hurley Alacrity
Posts: 370
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

The problem with fixing plastic tanks is the plastic with expand and contract a lot differently than the adhesive and it will separate eventually unless reinforced. If you can reach inside you can fabricate a metal plate or just use a bolt and a "fender washer". Epoxy one washer to the bolt and figure the placement on the outside and drill a hole for it. Glue a piece of stiff wire to the head of the bolt so you can feed it into the hole from the fuel filler neck. Now clean the plastic tank area with plastic pipe primer used for gluing PVC or ABS plumbing pipe together, clean on both inside and outside. Now mix some fuel proof epoxy and coat the washer/bolt combo and using the wire glued to the head feed the bolt through the hole. When it is through the hole coat the outside of the tank and the washer too, then put a nut on the bolt and tighten it all together. Once the nut is on the bolt and getting snugged down, you might need to grip the bolt with a pair of pliers while you use the wrench to finish tightening. The next day, yank off the epoxied wire and you're done.
__________________
MBWhite is offline   Reply With Quote
Old 05-10-2014, 09:34   #7
Registered User
 
FilBrown's Avatar

Join Date: Mar 2012
Location: TYC, West Thurrock, Essex
Boat: Moody 31 MkII 31'10"
Posts: 114
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

Have a look on EBay there's loads of second hand parts from defunct engines.
I've had some success in fixing cracked plastic parts using a soldering iron with a blade attachment. If it's the right kind of plastic I've found that you can carefully soften the surrounding area and pull some of the plastic into the gap.
You can also sometimes take excess plastic from flanges or struts moulded elsewhere on the part although don't take too much.
I also use epoxy to cover the area I've worked on to help strengthen it.
There's a bit of a knack to it getting the irons temperature right and practice on similar material would be recommended.

__________________
FilBrown is offline   Reply With Quote
Old 05-10-2014, 10:25   #8
Registered User
 
Sun and Moon's Avatar

Join Date: Nov 2009
Location: Colorado
Boat: Bristol 29
Posts: 273
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

Nimblemotors has it right. If it is HDPE, which I think it is, no glue will bond, including epoxy. PVC products won't work either. You must weld. You can do this yourself, although getting the temperature right is difficult. Too hot and it will melt or burn the tank, too cool and the plastic won't bond. When I've done this the plastic turns transluscent when the temperature is right. The plastic can also catch fire - not necessarily a problem, I just blow it out - but be prepared for that. Practice on some junk first.
__________________
Sun and Moon is offline   Reply With Quote
Old 05-10-2014, 12:03   #9
Registered User

Join Date: Aug 2008
Boat: Aries 32
Posts: 245
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

I've had great luck with 5200 - I've got a badly-cracked tank with a ~5-year-old patch holding up fine.
__________________
Dustymc is offline   Reply With Quote
Old 05-10-2014, 12:08   #10
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,358
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

This is the tank mounted inside the engine cowl right?
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is online now   Reply With Quote
Old 05-10-2014, 19:38   #11
Registered User
 
ErikFinn's Avatar

Join Date: Feb 2011
Location: Malaysia, Thailand
Boat: Beneteau Oceanis 430
Posts: 832
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

Quote:
Originally Posted by Cheechako View Post
This is the tank mounted inside the engine cowl right?
yup, the internal fuel tank, white thick hard plastic.
__________________
ErikFinn is offline   Reply With Quote
Old 05-10-2014, 19:40   #12
Registered User
 
ErikFinn's Avatar

Join Date: Feb 2011
Location: Malaysia, Thailand
Boat: Beneteau Oceanis 430
Posts: 832
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

Quote:
Originally Posted by nimblemotors View Post
What kind of plastic is it? That makes all the difference.
If it is HDPE or LDPE, you can 'weld' the cracks to seal them up.
Thanks but I have no idea what kind.. Would it be stamped on the tank somewhere possibly?
__________________
ErikFinn is offline   Reply With Quote
Old 05-10-2014, 19:44   #13
Registered User
 
ErikFinn's Avatar

Join Date: Feb 2011
Location: Malaysia, Thailand
Boat: Beneteau Oceanis 430
Posts: 832
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

Quote:
Originally Posted by Sun and Moon View Post
Nimblemotors has it right. If it is HDPE, which I think it is, no glue will bond, including epoxy. PVC products won't work either. You must weld. You can do this yourself, although getting the temperature right is difficult. Too hot and it will melt or burn the tank, too cool and the plastic won't bond. When I've done this the plastic turns transluscent when the temperature is right. The plastic can also catch fire - not necessarily a problem, I just blow it out - but be prepared for that. Practice on some junk first.
Would a soldering iron be appropriate for the job?
__________________
ErikFinn is offline   Reply With Quote
Old 05-10-2014, 19:50   #14
Registered User
 
ErikFinn's Avatar

Join Date: Feb 2011
Location: Malaysia, Thailand
Boat: Beneteau Oceanis 430
Posts: 832
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

Quote:
Originally Posted by FilBrown View Post
Have a look on EBay there's loads of second hand parts from defunct engines.
I've had some success in fixing cracked plastic parts using a soldering iron with a blade attachment. If it's the right kind of plastic I've found that you can carefully soften the surrounding area and pull some of the plastic into the gap.
You can also sometimes take excess plastic from flanges or struts moulded elsewhere on the part although don't take too much.
I also use epoxy to cover the area I've worked on to help strengthen it.
There's a bit of a knack to it getting the irons temperature right and practice on similar material would be recommended.

oh there we go hehe, I should have read this one before asking the one above re soldering iron (maybe another cup of coffee would help also )

But can you describe the "blade attachment" to me please? You mean instead of the normal "tip" you use some kind of a modified spade or similar shape tip?
__________________
ErikFinn is offline   Reply With Quote
Old 05-10-2014, 21:41   #15
Registered User
 
FilBrown's Avatar

Join Date: Mar 2012
Location: TYC, West Thurrock, Essex
Boat: Moody 31 MkII 31'10"
Posts: 114
Re: How to weld/glue/fix cracked outboard engine plastic fuel tank?

I use a small hot knife blade on a gas powered soldering iron.
The blade is only about 3cm long and doesn't have a sharpened edge.
I also use it for cutting & sealing synthetic ropes.

Sent from my HTC One_M8 using Cruisers Sailing Forum mobile app
__________________

__________________
FilBrown is offline   Reply With Quote
Reply

Tags
engine, fuel, fuel tank, outboard

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
J-B Weld on Aluminum ? unbusted67 Deck hardware: Rigging, Sails & Hoisting 12 26-02-2017 04:43
Cracked fiberglass hding tank Just us Plumbing Systems and Fixtures 11 08-09-2013 13:29
Plastic pipe as a fuel tank anontrolus Engines and Propulsion Systems 9 21-08-2012 08:46
Weld Repair of Yanmar Pan ? Chief Engineer Engines and Propulsion Systems 18 22-11-2010 15:47
Spreader Weld lockie Deck hardware: Rigging, Sails & Hoisting 3 14-05-2010 18:38



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 17:52.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.