Reply
 
Thread Tools Search this Thread
 
Old 15 July 2011, 18:44   #1
Member
 
Country: Sweden
Make: Bombard Aerotec
Length: 4m +
Engine: Evinrude 15 hp -78
Join Date: Jun 2011
Posts: 142
Just got an old air cooled Yamaha 5 HP

Hi

I've just bought (had to buy to get the boat) an old Yamaha 5 hp. It's probably from the 80's, and it's air cooled! All my previous engines has been water cooled, what's the difference? Why are there even air cooled ones?

The problem with it is that the spring that pulls back the rope after starting (don't know the terms for these things) doesn't work, so the rope will keep hanging outside the engine.

Otherwise it's been said that it should work very well. It hasn't got a built in tank. Is this engine any good or should I try to get rid of it right away?
__________________

__________________
Patrik is offline   Reply With Quote
Old 15 July 2011, 19:00   #2
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: 2 stroke YAM 20 HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 10,114
Quote:
what's the difference? Why are there even air cooled ones?
Air cooling has some advantages - most specifically that there is no cooling water circuit to fail (broken impeller, blocked intake, salt in water passages etc) which is one of the more common causes of catastrophic premature outboard engine death! [In theory the air cooling fan can fail too but this seems less likely to go unnoticed, and without proper maintainence as it is easier to access]. I'm not sure what all the disadvantages of air cooling are but the most obvious one will be the horrendous noise!

The main difference from a user perspective is that the engine runs hotter so is probably intended to use scooter/chainsaw/lawnmower 2 stroke oil rather than normal (TCW3) outboard motor oil.
__________________
Poly is offline   Reply With Quote
Old 15 July 2011, 19:15   #3
Member
 
Country: Sweden
Make: Bombard Aerotec
Length: 4m +
Engine: Evinrude 15 hp -78
Join Date: Jun 2011
Posts: 142
Hehe! I see, useful info. Practical that I won't need a bucket to test run it at home...
__________________
Patrik is offline   Reply With Quote
Old 15 July 2011, 19:37   #4
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
Quote:
Originally Posted by Patrik View Post
Hehe! I see, useful info. Practical that I won't need a bucket to test run it at home...
Actually, you might. Some aircooled motors had an impeller (thinking back to the Volvo penta aircooled 5hp) that's purpose was to pump cooling water through the exhaust to keep it from getting so hot it blistered.

Exactly what model is it? Got pics?
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 16 July 2011, 06:02   #5
Member
 
Country: UK - England
Town: East Anglia
Boat name: Nimrod II
Make: Aerotec 380
Length: 3m +
Engine: Suzuki DF20 EFI
Join Date: Nov 2007
Posts: 3,276
Is it the 5hp version of this one Patrik?



5hp looks just the same as the 3.5, I had one in the 1980s as a river engine for a 16ft fishing boat. Basic, reliable and very noisy. Just forward and neutral so you had to spin it right round to go in reverse, that's why it has a handle that goes right round.

Can't remember the exhaust cooling issue.
__________________
Fenlander is offline   Reply With Quote
Old 16 July 2011, 18:02   #6
Member
 
Country: Sweden
Make: Bombard Aerotec
Length: 4m +
Engine: Evinrude 15 hp -78
Join Date: Jun 2011
Posts: 142
Quote:
Originally Posted by Fenlander View Post
Is it the 5hp version of this one Patrik?
That was mad noisy!!

However I'm not sure it would be useful for me at that sound level, can't even go back to the cabin with that one after eight at night

EDIT: hmm found a picture of the engine, doesn't look as similar as I thought. I attach it.
Attached Thumbnails
Click image for larger version

Name:	Yamaha 2011 008.jpg
Views:	1150
Size:	135.2 KB
ID:	60888  
__________________
Patrik is offline   Reply With Quote
Old 17 July 2011, 05:21   #7
Member
 
Country: Sweden
Make: Bombard Aerotec
Length: 4m +
Engine: Evinrude 15 hp -78
Join Date: Jun 2011
Posts: 142
Now this looks more like it!
__________________
Patrik is offline   Reply With Quote
Old 17 July 2011, 06:56   #8
Member
 
spartacus's Avatar
 
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 60hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 3,268
RIBase
Quote:
Originally Posted by Patrik View Post
The problem with it is that the spring that pulls back the rope after starting (don't know the terms for these things) doesn't work, so the rope will keep hanging outside the engine.

Otherwise it's been said that it should work very well. It hasn't got a built in tank. Is this engine any good or should I try to get rid of it right away?
The fact the starter rope doesn't retract is probably a broken coil spring. If you're replacing the spring - then replace the starter rope too. Could be corrosion simply due to sitting around or general wear and tear from starting over the years. Not sure if Yamaha even sell the springs - or you could salvage one from someone that's breaking a similar engine. When new - they normally come with a film of machine oil on them. Without undoing the coil (important), lube up with a marine grease.

Regards getting rid - I'd have thought you'll be hard-pressed to find a buyer.
__________________
spartacus is offline   Reply With Quote
Old 17 July 2011, 07:28   #9
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: 2 stroke YAM 20 HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 10,114
Quote:
Originally Posted by spartacus
Regards getting rid - I'd have thought you'll be hard-pressed to find a buyer.
People buy any old motor on eBay. If the spring was fixed then I'd be surprised if it went for less that 100 pound.
__________________
Poly is offline   Reply With Quote
Old 17 July 2011, 07:35   #10
Member
 
spartacus's Avatar
 
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 60hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 3,268
RIBase
Quote:
Originally Posted by Polwart View Post
People buy any old motor on eBay. If the spring was fixed then I'd be surprised if it went for less that 100 pound.
True.
__________________

__________________
spartacus is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 12:02.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.