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15-01-2013, 06:26 PM
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#1
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Registered User
Country: UK
Location: Cowes,Isle of Wight.
Boat name: B-52
Cruising area: The Solent
Join Date: Aug 2006
Location: Cowes,Isle of Wight.
Posts: 99
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Yamaha v4 2stroke 140 problem
Posting for a friend.
Re.140hp yamaha fault = loss of spark on number 1 cyl, upper stb. If I swap the black and white primary feed wires, (from the CDI box to the coils), the loss of spark follows the swap over, so you could say the 4 coils, leads, 4 new suppressor/caps and plugs are ok. Checks are made using a spark tester set at 10mm @ cranking speed. I haven`t yet checked the resistance on the charge coil under the flywheel or the 2 pulse coils. On 4 or 5 outings during the year, the engine has had intermittent slow/idle and acceleration issues, but over 2000rpm and WOT, 5600rpm, it ran fine. During the last outing I made, the engine ran fine in all aspects, ie; idle, hard and soft acceleration, mid rpm speeds and seemless high speed. The outing lasted 2hrs continuous, faultless running. However, recently, I ran the engine at home on a hose flusher and it again was idling on 3cyls not 4. A spark test reveiled no spark at cranking speeds on cyl. number one, upper stb. Cylinders 2, 3 and 4 sparked ok with or without over/rev wire connected. Early during the season, I have checked fuel filters, new plugs, new suppressor caps, new themostats, idle mixture scew settings, new fuel line with primer. On all the info I have picked up recently it would seem I have a faulty CDI/switchbox but at £400 plus, I`m reluctant to buy, untill I`ve checked all the coils under the flywheel. Any help/advise etc. gratefully recieved, regards, Steve.
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15-01-2013, 09:33 PM
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#2
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Senior Member
Country: UK
Location: Devon
Occupation: Garage Proprietor
Interests: PowerBoat Racing
Boat name: If Only
Boat make: Bernico F3 OCR, Bernico Prototype Inboard, and some Ribs
Engines: Yamaha Pro V 115
Cruising area: UK, France
Join Date: Jan 2005
Location: Devon
Posts: 3,095
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Quote:
Originally Posted by gap52
Posting for a friend.
Re.140hp yamaha fault = loss of spark on number 1 cyl, upper stb. If I swap the black and white primary feed wires, (from the CDI box to the coils), the loss of spark follows the swap over, so you could say the 4 coils, leads, 4 new suppressor/caps and plugs are ok. Checks are made using a spark tester set at 10mm @ cranking speed. I haven`t yet checked the resistance on the charge coil under the flywheel or the 2 pulse coils. On 4 or 5 outings during the year, the engine has had intermittent slow/idle and acceleration issues, but over 2000rpm and WOT, 5600rpm, it ran fine. During the last outing I made, the engine ran fine in all aspects, ie; idle, hard and soft acceleration, mid rpm speeds and seemless high speed. The outing lasted 2hrs continuous, faultless running. However, recently, I ran the engine at home on a hose flusher and it again was idling on 3cyls not 4. A spark test reveiled no spark at cranking speeds on cyl. number one, upper stb. Cylinders 2, 3 and 4 sparked ok with or without over/rev wire connected. Early during the season, I have checked fuel filters, new plugs, new suppressor caps, new themostats, idle mixture scew settings, new fuel line with primer. On all the info I have picked up recently it would seem I have a faulty CDI/switchbox but at £400 plus, I`m reluctant to buy, untill I`ve checked all the coils under the flywheel. Any help/advise etc. gratefully recieved, regards, Steve.
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Almost certain to be CDI !! Is it the one with screw connections ? email me ocrda@btconnect.com and i will send you one but wont be till end of month.
Bob
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If Only
National Outboard Immersed Propeller Mono Record 103mph
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16-01-2013, 12:38 PM
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#3
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Registered User
Country: UK
Location: Cowes,Isle of Wight.
Boat name: B-52
Cruising area: The Solent
Join Date: Aug 2006
Location: Cowes,Isle of Wight.
Posts: 99
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Yam 140
Thanks Bob , i thought you might answer. Have passed details on.
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