Reply
 
Thread Tools Search this Thread
 
Old 19 August 2012, 16:36   #1
RIBnet supporter
 
Country: UK - England
Town: Ashton-under-Lyne
Boat name: El Presidente
Make: Humber Assault
Length: 5m +
Engine: Outboard, 70hp, 2st
Join Date: Jun 2009
Posts: 99
2 Stroke Mixture Problem

We've towed our SIB to Spain and on our 1st day, even before we got the boat in the water, we found a problem with the front tube. It's taken me a week but I found somewhere to have it repaired and i'll be collecting it tomorrow with the intention of launching tomorrow evening.

On the 1st day we arrived I filled the tank with 20 litres of fuel with the intention of adding oil at a 50 to 1 ratio. The fuel tank has sat in the shade for the past week but I've now found that fuel has been leaking out of the end of the hose. This has completely messed up my ratio calculation as I have no idea how much fuel has been lost.

Is it therefore better to overcalculate or undercalculate the ratio? Alternatively should I just discard the fuel and start again. We've already been without the boat for the 1st week of our holiday and the last thing I want to do is cause any problems with the engine for the 2nd week of our holiday.

Any ideas or suggestions?

Thanks.
__________________
Vincent Vega is offline   Reply With Quote
Old 19 August 2012, 16:42   #2
Member
 
jamie.rib's Avatar
 
Join Date: Apr 2012
Posts: 74
Just top the tank up to full again, or am I missing the point?
__________________

__________________
jamie.rib is offline   Reply With Quote
Old 19 August 2012, 16:45   #3
Member
 
kerny's Avatar
 
Country: UK - England
Town: Ashton-under-Lyne Lancs
Boat name: IMOGEN
Make: Air-Craft 5.4
Length: 5m +
Engine: Etec 60
MMSI: 235087492
Join Date: May 2010
Posts: 7,040
RIBase
Send a message via Skype™ to kerny
Quote:
Originally Posted by Vincent Vega View Post
We've towed our SIB to Spain and on our 1st day, even before we got the boat in the water, we found a problem with the front tube. It's taken me a week but I found somewhere to have it repaired and i'll be collecting it tomorrow with the intention of launching tomorrow evening.

On the 1st day we arrived I filled the tank with 20 litres of fuel with the intention of adding oil at a 50 to 1 ratio. The fuel tank has sat in the shade for the past week but I've now found that fuel has been leaking out of the end of the hose. This has completely messed up my ratio calculation as I have no idea how much fuel has been lost.

Is it therefore better to overcalculate or undercalculate the ratio? Alternatively should I just discard the fuel and start again. We've already been without the boat for the 1st week of our holiday and the last thing I want to do is cause any problems with the engine for the 2nd week of our holiday.

Any ideas or suggestions?

Thanks.
How much fuel have you lost ? if it's minimal ie cup full then I wouldn't worry but if you put a bit more oil in than you should have the engine will just smoke a bit more, rather more than less.
__________________
Member of S.A.B.S. (Lancashire Division)
kerny is offline   Reply With Quote
Old 19 August 2012, 16:54   #4
RIBnet supporter
 
Country: UK - England
Town: Ashton-under-Lyne
Boat name: El Presidente
Make: Humber Assault
Length: 5m +
Engine: Outboard, 70hp, 2st
Join Date: Jun 2009
Posts: 99
Quote:
Originally Posted by jamie.rib View Post
Just top the tank up to full again, or am I missing the point?
Hi Jamie,

It's a 22.7 litre fuel tank (from memory) so I've always put 20 litres in so that the calculation is simple. I've never been certain how exact the calculation needs to be so I've always been as exact as possible.

Cheers
__________________
Vincent Vega is offline   Reply With Quote
Old 19 August 2012, 16:55   #5
RIBnet supporter
 
Country: UK - England
Town: Ashton-under-Lyne
Boat name: El Presidente
Make: Humber Assault
Length: 5m +
Engine: Outboard, 70hp, 2st
Join Date: Jun 2009
Posts: 99
Quote:
Originally Posted by kerny View Post
How much fuel have you lost ? if it's minimal ie cup full then I wouldn't worry but if you put a bit more oil in than you should have the engine will just smoke a bit more, rather more than less.
Thanks Kerny. I'm assuming that the loss will be minimal. If I just assume 20 litres and overdo the oil slightly i'll just see a more smoky engine? I can live with that as long as I can get out on the water at last.

Btw, how's the weather in sunny Ashton? ;-)
__________________
Vincent Vega is offline   Reply With Quote
Old 19 August 2012, 17:00   #6
Member
 
kerny's Avatar
 
Country: UK - England
Town: Ashton-under-Lyne Lancs
Boat name: IMOGEN
Make: Air-Craft 5.4
Length: 5m +
Engine: Etec 60
MMSI: 235087492
Join Date: May 2010
Posts: 7,040
RIBase
Send a message via Skype™ to kerny
Quote:
Originally Posted by Vincent Vega View Post
Thanks Kerny. I'm assuming that the loss will be minimal. If I just assume 20 litres and overdo the oil slightly i'll just see a more smoky engine? I can live with that as long as I can get out on the water at last.

Btw, how's the weather in sunny Ashton? ;-)
If it was premixed in the tank already it wouldn't matter if you leaked half your tank you wouldn't need to add any more oil.

You will be pleased to know that it is warm but wet in sunny- less Ashton
__________________
Member of S.A.B.S. (Lancashire Division)
kerny is offline   Reply With Quote
Old 19 August 2012, 17:27   #7
Member
 
kubcat's Avatar
 
Country: Australia
Town: Sydney
Boat name: Lunasea
Make: Ribtec 890SX
Length: 8m +
Engine: Yamaha ME 421STI x 2
Join Date: Aug 2009
Posts: 470
Just to recap.

After filing the fuel tank you had at least 20 litres of fuel with no oil. Oil was to be added later.

The tank capacity is 22.5 litres so there could not have been more than 22.5 litres of fuel including anything that may have been in it before that was mixed with oil.

I suggest fill the tank to full and then just add oil for 22.5 litres so the most extra oil you would have would be 10% which I doubt you would notice.

Or am I missing the point completely?
__________________
kubcat is offline   Reply With Quote
Old 19 August 2012, 17:29   #8
RIBnet admin team
 
willk's Avatar
 
Country: Ireland
Make: Redbay Boats
Length: 9m +
Engine: 370hp
Join Date: Feb 2008
Posts: 12,925
RIBase
Um, the catch is that most of those tanks fill to over 25L if you push them. That might be the way to go (fill and add oil for 25L) but there will be less expansion room in what will be a hot location.

I'd just eyeball fill the tank to 4/5 and add oil for 20L. It will be close enough, especially if you don't run the motor at WOT a lot.
__________________
willk is offline   Reply With Quote
Old 19 August 2012, 18:21   #9
Member
 
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,962
Quote:
I suggest fill the tank to full and then just add oil for 22.5 litres...
So if you fill the tank, how're you gonna find the space to get the oil in?
__________________
JW.
jwalker is offline   Reply With Quote
Old 19 August 2012, 18:25   #10
Member
 
kerny's Avatar
 
Country: UK - England
Town: Ashton-under-Lyne Lancs
Boat name: IMOGEN
Make: Air-Craft 5.4
Length: 5m +
Engine: Etec 60
MMSI: 235087492
Join Date: May 2010
Posts: 7,040
RIBase
Send a message via Skype™ to kerny
Quote:
Originally Posted by jwalker View Post
So if you fill the tank, how're you gonna find the space to get the oil in?
__________________

__________________
Member of S.A.B.S. (Lancashire Division)
kerny 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 14:14.


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