Reply
 
Thread Tools Search this Thread
 
Old 24 August 2007, 10:28   #21
Member
 
Country: UK - England
Town: Dorset & Hants
Boat name: Streaker/Orange
Make: Avon/Ribcraft
Length: 4m +
Engine: 50Yam/25 Mariner
Join Date: Apr 2007
Posts: 5,551
Surely car engines wont last as long - they are started form cold far more often ( several times a day ) depending on how you drive . I remember BMW put 1,000,000 miles on one its 2l engines with only routine service - and when they stripped it i was still within original tolerance for leaving the factory !
Surely its not the actual engine that fails - its the ancillary stuff - starter / fuel pump etc from the environment ?

Is it harder thrash an OB from cold (?) as most boats are launched from places with a few minutes at least to warm them up before anywhere near WOT ? Cars - max revs in the first 50m if you want to in each gear !
__________________

__________________
PeterM is offline   Reply With Quote
Old 24 August 2007, 18:20   #22
Member
 
Country: UK - England
Town: cornwall
Boat name: nothing
Make: rib eye 430
Length: 4m +
Engine: tatsu 50
MMSI: 666
Join Date: Mar 2006
Posts: 1,916
Seems there are lost of ways of looking at it , all make some sence .

Duncan iam interested how you can work out hop many HP your engine is making from measuring air flow ?? and how you can monitor airflow .
__________________

__________________
ian parkes is offline   Reply With Quote
Old 25 August 2007, 13:48   #23
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: 3,688
Quote:
Originally Posted by ian parkes View Post
Seems there are lost of ways of looking at it , all make some sence .

Duncan iam interested how you can work out hop many HP your engine is making from measuring air flow ?? and how you can monitor airflow .
EFI engines normally have an airflow meter for engine management and I guess if you assume a fairly constant fuel:air ratio then you can work out how much fuel it is burning and thus how much power you are generating. Well in theory anyway...
__________________
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 25 August 2007, 15:49   #24
Member
 
Country: UK - England
Town: cornwall
Boat name: nothing
Make: rib eye 430
Length: 4m +
Engine: tatsu 50
MMSI: 666
Join Date: Mar 2006
Posts: 1,916
Quote:
Originally Posted by BogMonster View Post
EFI engines normally have an airflow meter for engine management and I guess if you assume a fairly constant fuel:air ratio then you can work out how much fuel it is burning and thus how much power you are generating. Well in theory anyway...

Like the economy lights and so called MPG computers that some cars have . Mine used to do 99mpg down hill
__________________
ian parkes is offline   Reply With Quote
Old 27 August 2007, 07:10   #25
Member
 
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,611
99 is easy to achieve depending how your MPG-ometer is calibrated - Assuming you have fuel injection, the Engine management knows how long the injector has been open and how many times it has done so in a given time. Take a distance reading from the odometer , one quick division and job done.

The "99mpg" is simply becaise you are gravity assisted down a hill. Assuming you're doing steady speed, all you are doing is overcoming the friction in the engine & bearings, tyre drag and above about 40mph, wind resistance. Downhill there is every chance that the slopw will be more than enough to overcome that. There will be just enough fuel being squirted in to keep the emmissions low (i.e keep the catalyst warm - otherwise it could be switched off entirely, giving an instantanious "infinite" MPG 'coz you wouldn't be burning fuel, but you would be covering distance). If the compooter takes the "instantaneous" reading over, say, the last 20m, then you will easily clock 99.9 - probably more, but your display will only have 2 or 3 digits!

I had a drive in a new Focus recently, it doesn't have an "instantaneous" MPG reading, but if you reset the rolling average (according to the manual it looks at the last 600 miles), it will show 99.9 if you reset it on a downhill, but will only show you a number after a good few hundred metres of driving. (it's taking the average over a longer sdistance) After the first bit of level or uphill you will never see 99.9 ever again! (until you reset it on another downhill stretch)

Yeah could be very theoretically sussed out by airflow, but why bother when you have a VERY accurately calibrated set of injectors you can use.......
__________________
9D280 is offline   Reply With Quote
Old 27 August 2007, 22:39   #26
Member
 
Country: UK - Wales
Town: swansea
Boat name: Too Blue
Make: BLANK
Length: 8m +
Engine: Suzuki DT225
Join Date: Mar 2004
Posts: 12,791
I have had cars with fuel computers that read much higher than 3 digits. Best I ever saw was 3860 mpg in a Rover SD1 vitesse - down a steep hill at about 100mph in neutral. Going up it was reading 6mpg!!! The worst reading though for any car - even a 1.0L is in a traffic jam - 0mpg - that's why you should switch off.......
__________________
codprawn is offline   Reply With Quote
Old 28 August 2007, 01:15   #27
Member
 
Country: Canada
Town: Tobermory, Canada eh
Boat name: Verius
Make: Zodiac Hurricane 590
Length: 5m +
Engine: Yamaha F150
Join Date: Oct 2006
Posts: 1,345
Send a message via MSN to Stoo
So how come that in 9 years of use, I have blown two heads on my Yammy 150? I maintain it, run nothing but Yamalube, have it professionally winterized and stored indoors. The guy who replaced the last head, and who is a friend as well, suggested that many manufacturers quietly suggest that their engines are really only designed for a life span of about 1000 hours. Personally I can't beieve that. I believe a read that the average guy runs his engine less than 100 hours a year, but if 1000 hours is right, wouldn't we be storming the plants and buring them to the ground? Incidently, no one has ever found a reason for the meltdowns (i.e. busted oil pump, plastic bag in the impellor etc.) Just good old fatigue...

Either way, I have spent $16,500 on replacement heads! Other than that small detail, the thing runs like a clock!
__________________
Pump it up and RIDE!

www.wetspotimages.com
Stoo is offline   Reply With Quote
Old 28 August 2007, 09:28   #28
Member
 
Country: UK - England
Town: cornwall
Boat name: nothing
Make: rib eye 430
Length: 4m +
Engine: tatsu 50
MMSI: 666
Join Date: Mar 2006
Posts: 1,916
Quote:
Originally Posted by Stoo View Post
So how come that in 9 years of use, I have blown two heads on my Yammy 150? I maintain it, run nothing but Yamalube, have it professionally winterized and stored indoors. The guy who replaced the last head, and who is a friend as well, suggested that many manufacturers quietly suggest that their engines are really only designed for a life span of about 1000 hours. Personally I can't beieve that. I believe a read that the average guy runs his engine less than 100 hours a year, but if 1000 hours is right, wouldn't we be storming the plants and buring them to the ground? Incidently, no one has ever found a reason for the meltdowns (i.e. busted oil pump, plastic bag in the impellor etc.) Just good old fatigue...

Either way, I have spent $16,500 on replacement heads! Other than that small detail, the thing runs like a clock!

It is hard to explain , is the head a common problem on the Yam 150 or have you just been unlucky.
there have been many engines over the years famouse for cracking and warping cylinder heads ie most diesel engines from the last decade and every british built car from the 60's 70's etc Hilman imp triumph dolomite sprint , stag etc, and the Japs were probably the first to be able to make an alloy head that didn't warp . Still lots today that are crap .
__________________
ian parkes is offline   Reply With Quote
Old 28 August 2007, 13:29   #29
Member
 
Country: Canada
Town: Tobermory, Canada eh
Boat name: Verius
Make: Zodiac Hurricane 590
Length: 5m +
Engine: Yamaha F150
Join Date: Oct 2006
Posts: 1,345
Send a message via MSN to Stoo
Quote:
Originally Posted by ian parkes View Post
It is hard to explain , is the head a common problem on the Yam 150 or have you just been unlucky.
Certainloy rhe first one looked like the head might have been warped... there had been some signs of water penetrating. The second one showed no such signs...

Guys like me (i.e. ones that don't know anything about motors) just figure that they should work for a really long time, especially when they are well-maintained. I recently bough a new dive tank, and after a year and only about five uses in fresh water, it was rusted out under the boot. The manufacturer told me that I should have removed the boot after each dive and dried the tank! As a result, my warranty was voided. (Ya, I know this has nothing do do with engines, just strikes me as a dumb way to build a dive tank... or an engine!)
__________________
Pump it up and RIDE!

www.wetspotimages.com
Stoo is offline   Reply With Quote
Old 28 August 2007, 15:55   #30
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: 3,688
I figure a Yamaha should work for a really long time otherwise what is the point in spending the extra cash over the cost of any other engine...
__________________

__________________
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

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 04:25.


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