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Old 24 March 2002, 15:10   #1
Country: Ireland
Town: Loch Lurgain
Boat name: an t-easnach
Make: Gemini
Length: 5m +
Engine: Honda 50
Join Date: Oct 2000
Posts: 138
suzuki 70 4-stroke cutting out

after the winter break (didn't drain the petrol) on the first run at sea my suzuki 70 started idling roughly before cutting out. it started again and ran no bother but i was a bit worried obviously. today i started her out of the water and she ran for 5 mins before stalling. started no problem again then ran for 2 mins; 30 secs and now she cuts out on starting. i cleaned all the plugs, checked breathers but no good. Got a mechanic looking at her next week but any ideas? I suspect the fuel but it all looks fine.

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Old 24 March 2002, 15:23   #2
Country: UK - Wales
Town: Pwllheli-North Wales
Boat name: Delta 1
Make: Delta
Length: 6m +
Engine: Mariner 90hp Optimax
Join Date: Mar 2001
Posts: 2,367
Could be the float sticking..?..?


Have you tried totally running the carb dry? ie disconnect the fuel pipe and leave engine running till stops. Then connect and try.

Hope you sort your problems out..........

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Old 24 March 2002, 15:52   #3
Country: UK - England
Town: Worcestershire
Boat name: Not Yet Named
Make: Avon SR 4
Length: 4m +
Engine: 40 HP Yamaha Autolub
Join Date: Sep 2001
Posts: 600
I think your problem may well be 'stale' petrol.

The Old 4 Star fuel did not surffer this problem, but the new Unleaded contains high amounts of water, and, if left for any period, 'goes off'.

I discovered this to my cost with a lawnmower a couple of years ago, and the local dealer merely emptied the fuel, replaced it and all was well. I felt a bit of an idiot.

I have an old Military Landrover that is used only rarely, and I have found an additive that removes the water and therefore prevents this from happening.

You may find you will need to get this additive - available from any garage, or your local marina, and run it through. If you can get rid of most of your old fuel that may also help.
Carpe pm
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Old 25 March 2002, 09:25   #4
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Country: UK - Isle of Man
Town: Peel, IOM
Length: no boat
Join Date: Nov 2000
Posts: 2,301
I've got a theory. Same thing happened to me.
The cause was a small "tear" or "pinprick" in the furel line. You wouldn't credit it, but that was the problem. Easily tested by running a diferent fuel line from a tank directly into your engine fuel coupling. Even the smallest amount of air getting into the engine will cause it because it's easier for the engine to suck air than it is for it to suck petrol.
Good luck and lets hope its resolved soon.
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Old 30 March 2002, 10:37   #5
Country: Ireland
Town: Loch Lurgain
Boat name: an t-easnach
Make: Gemini
Length: 5m +
Engine: Honda 50
Join Date: Oct 2000
Posts: 138
thanks for the help lads. i ran it dry jahno but the same trouble again. i supplied new fuel graeme but no improvement. as for a prick brian, i fell a bit of one myself but i cannot find one on the fuel line. one thing that puzzles me is that when i squeeze the handpump (the yoke that looks like a handgrenade) i notice it doesnt go completely hard and i seem to remember it used to. i cant find a leak between it and the carb though. mechanic coming monday thank god.
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Old 30 March 2002, 14:24   #6
Country: UK - England
Boat name: Won't get Fooled Again
Make: Ribtec
Length: 6.5
Engine: Honda 130
Join Date: Mar 2002
Posts: 888
regarding your comments about squeezing the handpump I think it's just as well that Nadia didn't read it.

Seriously though my son and I will be out on Monday in our ribs in the Solent, so if you need an escort while you give your engine a sea trial it will be no problem.
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Old 31 March 2002, 12:00   #7
Country: UK - England
Town: Great Harwood, Lancs
Boat name: Tigger II
Make: Bombardier Aerodeck
Length: 3m +
Engine: Tohatsu 25HP
Join Date: Jul 2001
Posts: 626
Hi gaelforce

Its worth trying pumping the primer bulb while the engine is running, say every 15-30 seconds.

By doing this you can rule out the fule pump, which the diaphram somtime perish when stood, or holes in the fule line as prining would push fule out whaile the normal pump would suck air in.

It may be worth waiting until the motro start to splutter then pump the bulb to see it recovers, if it does its likly to be fule starvation cause by somthing.

The othet thing that can help are the 2 stroke fuel system cleaners. These help remove old oil, left after the p[etrol evaporates and other goo from the engine. However they can take several gallons of fuel to do a good job so may be a problem.

Hope this helps Gary
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Old 02 April 2002, 05:55   #8
Country: UK - England
Town: Leatherhead
Length: no boat
Join Date: Aug 2001
Posts: 907
Could it be that the non-return valve in the primer bulb has failed and is letting fuel run back to the tank. It would appear that your short time of running is on carb contents only. This would also confirm your comments about the bulb not being as hard as it used to be.

Or has your engineer sorted out the problem?
Peter (nick, nick) T

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Old 02 April 2002, 23:34   #9
Country: Greece
Boat name: SUN KISS II
Make: Nuova Bat 9 Falcon -
Length: 5m +
Engine: Outboard Mercury 115
Join Date: Jun 2001
Posts: 639
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Try to remove

the fuel line from the carbs and pump the hand pump. If the fuel come out from the pipe then the problem must be in the carbs. First "feel" the fuel. Smell it. Does it smell like gas or it seams like water. If the fuel is ok, then try to blow some air in the carb(s) by attaching a spare fuel line on the carb and blowing your breath in it. If you feel that the air IS NOT inserting, then the carb's needle inside the bowl is blocked in place and doesn't let the fuel to flow freely.
Now if you feel that you can go on repairing, tell me and I'll try to guide you.
Michael a.k.a "Bat Falcon"

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Old 03 April 2002, 00:52   #10
Country: UK - N Ireland
Town: Bangor
Make: Shakespeare
Length: 7m +
Engine: O/b 225
Join Date: Jan 2001
Posts: 188
The Suzuki 70 4 stroke doesn't have any carbs! Anyway the seal at the fuel connector is worth checking- it is a common fault to get slight damage to the o ring seal and draw in air at this point and cause stalling.

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