Go Back   RIBnet Forums > RIB talk > Engines & props
Click Here to Login

Reply
 
Thread Tools Search this Thread
 
Old 12 January 2020, 10:35   #1
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,726
Merc 4hp flushing port thread damage

I have a Merc 4hp Saildrive that I use as my aux.


The hose flushing attachment fits into the bottom of the engine casing, you take out a small threaded plug and screw in the hose attachment which has the same thread. Mine has a short tail of hosepipe and a normal hose connector that I then fit onto the garden hose.



Unfortunately over a number of years of use taking the plug out and fitting the adaptor, the threads have badly worn on the engine side (guessing it is probably just aluminium), and it now barely grips. Apart from worrying about the plug popping out and losing cooling water, it means I dare not remove it again to flush the engine, and I don't want to have to set up a tank each time as it is a pain.


I am pretty sure a helicoil type thread repair won't work as the engine obviously has a cavity on the inside and helicoils are not really designed for that. There's also dissimilar metal corrosion to think about with a stainless helicoil against whatever the engine casing is, plus hot salt water!



My other thought is to try and find a thread adaptor and drill it through, drilling out the engine port and tapping it to the next size up (e.g. M8 to M10), fit the adaptor in with loctite and then just screw the blanking plug or the flushing adaptor into the thread adaptor.



This sort of thing https://www.jpldirect.co.uk/catalog/...rs_E30400.html


Before I order some (nothing like that available locally) I wondered if anybody might have other ideas that I hadn't thought of, or had come up with a solution to the same problem in the past?


Thanks.
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 12 January 2020, 23:23   #2
Member
 
spartacus's Avatar
 
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 70hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 4,650
RIBase
Time sert? Helicoil will just corrode. Fine if it was fit and forget, but you're likely to be flushing after every trip, so not up to the job.

I had steel inserts fitted on my Tohatsu cylinder head for threaded spark plugs. Stronger that the surrounding alloy.
__________________
Is that with or without VAT?
spartacus is offline   Reply With Quote
Old 13 January 2020, 09:26   #3
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,726
Thanks, not something I have come across, looks like a good idea but quite expensive on Amazon as a one-off (£150 for the set) - will look around and see if I can find it from another UK supplier.


That's what I think, the helicoil option will swell with corrosion and probably seize/repeat the problem.
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 13 January 2020, 09:50   #4
Member
 
Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: S/R5.4/regal3760
Length: 10m +
Engine: Suzukidf70 2x6lp 315
Join Date: Jul 2009
Posts: 4,027
I'm not sure the helicoil will be the problem you think if you insert with something like loctite it should fill the voids between the stainless coil and the aluminium case. Volvo penta use helicoils as standard in a lot of their outdrives so it must work ok. I've used timeserts in the past and iirc they are carbon steel which will corrode worse than the stainless helicoil. If it was mine I'd install a helicoil with plenty loctite and put plenty of aqualube grease on everytime i flushed it
__________________
beamishken is offline   Reply With Quote
Old 13 January 2020, 09:52   #5
Member
 
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 1,431
Is it possible to permanently seal the port & flush using muffs?
__________________
paintman is offline   Reply With Quote
Old 13 January 2020, 15:42   #6
Member
 
Locozodiac's Avatar
 
Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider 450 Rib
Length: 4m +
Engine: Tohatsu 5/18/30 HP
Join Date: Sep 2007
Posts: 1,998
That's the issue about unscrewing, screwing back on constant basis said bolt located under the powerhead. Install a Helicoil and grease the bolt to prevent corrosion if any.

If the flushing is done on dry land, preferibly use a bucket of a regular size with motor sitting vertical on a motor stand to avoid using the flushing port constantly.

Happy Boating
__________________
Locozodiac is offline   Reply With Quote
Old 13 January 2020, 16:44   #7
Member
 
Country: UK - England
Town: Retford
Boat name: Spy-sea-one
Make: Excel 435
Length: 4m +
Engine: Suzuki Outboard/25/4
Join Date: Oct 2011
Posts: 7,532
RIBase
https://www.amazon.co.uk/Thread%C2%A...27060789&psc=1
__________________
jeffstevens763@g is offline   Reply With Quote
Old 17 January 2020, 23:59   #8
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,726
OK, thanks all. I'll come up with something from one or other of the above ideas!
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Reply


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




All times are GMT. The time now is 09:10.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.