|
|
14-08-2006, 01:14 PM
|
#1
|
Registered User
Country: UK
Location: Coventry (but from Lee on Solent)
Occupation: Sales Director
Interests: My Boat of course
Boat make: Extreme 21
Engines: Merc V8
Cruising area: Solent
Join Date: Jul 2005
Location: Coventry (but from Lee on Solent)
Posts: 587
|
Poorly mota
Hi All
Wondered if anyone might have any ideas why my motor is not performing as it should. Its a late 80's 200 hp v6 merc (carb). Just been serviced with new plugs and leads.
Compression check was fine on all cylinders but the motor is not running right. It ticks over fine in neutral and throttle response is very good also sounds fine when given plenty of gas in neutral.
In gear, however, throttle response is poor and it sounds rough when running at low revs / speeds (almost like its missing). Only reaching about 45 - 50 at WOT where as we are used to more like 55-60+ and it sounds like its not reving as high as it should (guage knackered so cant be precise).
Also boat stalled totally when running at flat out yesteday but then started up without any probs??.
I thought it could be fuel related and was gonna replace filter. We normally run 45:1 mix with quicksilver oil.
Any ideas or suggestions would be more than appreciated.
Cheers all - the doc
ps attached a pic of the poorly mota in question
__________________
__________________
The Docta
|
|
|
14-08-2006, 03:05 PM
|
#2
|
Registered User
Country: England
Location: South West
Occupation: Development engineer
Interests: Fast boats
Boat name: Xtreme
Boat make: Bernico 21
Engines: Mercury F1, 300 Drag, XR2 "Fingerported"
Cruising area: South West
Join Date: Mar 2004
Location: South West
Posts: 1,043
|
Have you checked for a spark on all six cylinders?
looks like a clip on fuel line from the picture above, try removing the quick connect and fitting the hose straight to the carbs.
Also check the breather on the fuel tank is clear or open if its a remote tank.
Do you have a primer bulb? if so get someone to pump it whilst you are going along to see if the problem is fuel related, might be the mechanical fuel pump diaphrams.
__________________
|
|
|
14-08-2006, 03:09 PM
|
#3
|
Registered User
Join Date: Mar 2004
Posts: 6,891
|
Agree with cye comments. Have had occasions where an air leak in the fuel supply means the motor is sucking air and starving the top cylinders of fuel.
|
|
|
14-08-2006, 03:22 PM
|
#4
|
BananaShark Member
Country: UK
Location: Salcombe South Devon
Occupation: Racer and builder
Interests: Winning races
Boat name: BananaShark
Boat make: BananaShark 34' Race
Engines: Twin Yanmar BY 260's
Join Date: Mar 2004
Location: Salcombe South Devon
Posts: 4,638
|
Another reason for the above is water in the fuel ......... maybe!
__________________
Cookee
British Champions! RIB Formula 1 2005
National Speed Record Holder at 90.15 (still)
www.bananasharkracing.com
|
|
|
14-08-2006, 03:26 PM
|
#5
|
Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
|
Agree with all above, If it was running OK before Plugs & Leads have a look there also test insulation of plug leads with a cheap check tool
|
|
|
15-08-2006, 08:34 AM
|
#6
|
Registered User
Country: UK
Location: Coventry (but from Lee on Solent)
Occupation: Sales Director
Interests: My Boat of course
Boat make: Extreme 21
Engines: Merc V8
Cruising area: Solent
Join Date: Jul 2005
Location: Coventry (but from Lee on Solent)
Posts: 587
|
Hi Cyco, Cookee, Matt and Blufin
Thanks for the replies. The mota started playing up just b4 the service. That was why I insisted on new leads (+ plugs). I havnt checked sparks but assumed all cylinders were firing as it sounds spot on in neutral and thought that this would have been checked as part of service / compression check.
Can you check sparks in same way as car - ie remove plug with lead attached and hold against block??
There is a primer bulb on the fuel line so I will give that a try whilst running. I will also check lead for air leaks and check breather on tank.
Thanks again for all your advice
The doc
__________________
The Docta
|
|
|
15-08-2006, 08:57 AM
|
#7
|
Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
|
I understood it was since the plugs & leads were changed. You check the spark the same way but I was thinking more of the leads breaking down and going to earth underload at the higher RPM. Here is a pic of the basic one tiz about 3 quid.
That said as it was before the plugs I'd start with the fuel system, been sitting with any petrol in it for a while?
A nice easy way to check plugs is to make up a plug bar with some older plus that you know are OK and mount them in a metal bar about 2" wide and 7" long fix a wire from the end to a decent spring clip. all you need to do then is connect the sping clip to the block eart point, leads to the plugs on the bar & crank, saves wasting time pulling the plugs
__________________
It is impossible to lick your elbow.
Team25Racing.com
At least 75% of people who read this will try to lick their elbow!
|
|
|
15-08-2006, 09:11 AM
|
#8
|
Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
|
A really quick crappy sketch of what I mean simple home build
For a V6 I'd use a longer strip & put 6 plugs in it . Plugs go where the black sploges are Go the fuel route first
__________________
It is impossible to lick your elbow.
Team25Racing.com
At least 75% of people who read this will try to lick their elbow!
|
|
|
15-08-2006, 09:55 AM
|
#9
|
Registered User
Country: uk
Location: Lancaster
Occupation: Ambulance Chaser
Interests: Sailing and going slowly.
Boat make: loser pussycat
Engines: V8
Cruising area: Used to be Windermere!
Join Date: Jan 2006
Location: Lancaster
Posts: 74
|
Blufin,
Where did you get your tester gizmo from? I've never seen one before and need to add it to my tool kit.
|
|
|
15-08-2006, 10:16 AM
|
#10
|
Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
|
Good simple cheap effective gizmo to check HT voltages over did the price they are £2.50. had my one years but you can get them From Here Bottom Of The Page
__________________
It is impossible to lick your elbow.
Team25Racing.com
At least 75% of people who read this will try to lick their elbow!
|
|
|
15-08-2006, 11:20 AM
|
#11
|
Registered User
Country: uk
Location: Lancaster
Occupation: Ambulance Chaser
Interests: Sailing and going slowly.
Boat make: loser pussycat
Engines: V8
Cruising area: Used to be Windermere!
Join Date: Jan 2006
Location: Lancaster
Posts: 74
|
Cheers, ordered one already!
|
|
|
15-08-2006, 11:36 AM
|
#12
|
Registered User
Country: UK
Location: Coventry (but from Lee on Solent)
Occupation: Sales Director
Interests: My Boat of course
Boat make: Extreme 21
Engines: Merc V8
Cruising area: Solent
Join Date: Jul 2005
Location: Coventry (but from Lee on Solent)
Posts: 587
|
Hi Blufin
Cheers - I will start with the fuel then move on to the ignition circuit.
Fuel has been sitting in the tank (bow mounted 100 litre) for a good few months. Last time she ran dry was about three months ago. Since then she has been refilled and then topped up a couple of times. I will also check the breather. Would you suggest draining the tank
Also what about changing the fuel filter? could a dirty filter cause such a problem? The thing that I really dont understand is why it seems to run so sweet in neutral - I assume it draws a lot more fuel while in gear (and hence under load)
Cheers
The doc
__________________
The Docta
|
|
|
15-08-2006, 11:37 AM
|
#13
|
Registered User
Country: UK
Location: Coventry (but from Lee on Solent)
Occupation: Sales Director
Interests: My Boat of course
Boat make: Extreme 21
Engines: Merc V8
Cruising area: Solent
Join Date: Jul 2005
Location: Coventry (but from Lee on Solent)
Posts: 587
|
Another mota pic - really hoping to get this sorted by cowes powerboat weekend - hope to see lots of you there!
__________________
The Docta
|
|
|
15-08-2006, 11:51 AM
|
#14
|
Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
|
Fuel will go "off" the time frame depends on the ambient conditions and how good it was to start with, filters, Lines, Jets, ect ect clean them out with something that will get rid of the muck/gel
I use Ambersil FE10 or ME20, stings like bugger on cuts & excellent at lighting BBQ's. But you need to practice that a bit
I get mine through work but you can get it from a place in Southampton (click here)
EDIT: They do a load of good stuff have a look round the web site, solvent, glues, putties & all the Devcon stuff but need to route round the site.
Yes no load & loaded conditions make a big difference
__________________
It is impossible to lick your elbow.
Team25Racing.com
At least 75% of people who read this will try to lick their elbow!
|
|
|
15-08-2006, 12:56 PM
|
#15
|
Registered User
Country: UK
Location: Weston Super Mare
Occupation: Electrical Engineer
Join Date: Mar 2004
Location: Weston Super Mare
Posts: 6,351
|
fuel starts to deteriate after a 1000 hours thats about 41 days. and thats not from when you bought it either thats from when its made.
Jay Smith told me that
|
|
|
15-08-2006, 01:11 PM
|
#16
|
Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
|
Dont I know it 3 carb rebuilds
1/ chainsaw
2/ strimmer
3/ hedgecutter
coz I forgot to drain them last year
|
|
|
15-08-2006, 01:20 PM
|
#17
|
Registered User
Country: UK
Location: Weston Super Mare
Occupation: Electrical Engineer
Join Date: Mar 2004
Location: Weston Super Mare
Posts: 6,351
|
thats not saying its unusabe after that point just it starts to lose its goodness. The main problem is when the fuel and oil mix and then it conjelles ( cant spell) and sticks to everything.
|
|
|
15-08-2006, 01:29 PM
|
#18
|
Traveling
Country: UK
Location: Alderholt
Occupation: Aerospace
Boat name: T/T D2S
Boat make: Midas 27' Cat, Argo 16 Cat. Avon Rib Thingy
Engines: Merc 280-ROS -JSRE,65Xs, 75 Stinger, Yam 60
Cruising area: Any Seedy Bar
Join Date: Sep 2004
Location: Alderholt
Posts: 4,225
|
Congeals but I cheated
|
|
|
15-08-2006, 02:30 PM
|
#19
|
Registered User
Country: UK
Location: Southampton
Occupation: Software Developer
Interests: Pouring loads of money into the boat
Boat name: Blue Temptress
Boat make: Shakespeare 610
Engines: Promax 200
Cruising area: Southampton Water/Solent
Join Date: Apr 2006
Location: Southampton
Posts: 17
|
I had exactly the same problem with my Suzuki DT140, turned out to be the carbs and crap in them, had them cleaned properly and now it's running like a dream.
|
|
|
15-08-2006, 06:35 PM
|
#20
|
Registered User
Country: uk
Location: Bristol area
Occupation: Electrician
Interests: mmm stella
Boat make: 16 reiver
Engines: mercury 125 optimax
Cruising area: Lyme Bay
Join Date: Mar 2006
Location: Bristol area
Posts: 344
|
Quote:
Originally posted by lasermatrix
I had exactly the same problem with my Suzuki DT140, turned out to be the carbs and crap in them, had them cleaned properly and now it's running like a dream.
|
I had the same problem with my suzuki 90dt after i left the fuel in it one winter so had to have them cleaned out too.
I remember a thread on here from a guy (cant remember who) but he said... unleaded fuel has a shelf life of only 2000 hours.
__________________
|
|
|
|
|
Thread Tools |
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Threads |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|