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02 November 2014, 12:47
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#1
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Member
Country: UK - England
Town: swanage
Make: Thundercat
Length: 4m +
Engine: Tohatsu 50
Join Date: Apr 2012
Posts: 968
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No spark....help!!
I have a yamaha v4 115hp that has no spark on any of the plugs!
Tried switching coils around, cleaned the plugs.
There's fuel getting to the cylinders, it turns over but won't fire!
Any got any ideas??
Thinking it might be the coils but not 100% sure
Cheers! 
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02 November 2014, 13:06
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#2
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Member
Country: UK - England
Town: Southampton
Boat name: Hissing Sid
Make: Ross Smith Cobra
Length: 6m +
Engine: 200HP Optimax
MMSI: 235038046
Join Date: Jun 2002
Posts: 3,804
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Kill cord circuit ok?
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02 November 2014, 13:40
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#3
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Member
Country: UK - England
Town: swanage
Make: Thundercat
Length: 4m +
Engine: Tohatsu 50
Join Date: Apr 2012
Posts: 968
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Yep, checked all the fuses too.
Had one plug sparking briefly then stopped
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02 November 2014, 14:52
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#4
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Member
Country: UK - England
Town: Leeds
Make: Valiant 450
Length: 4m +
Engine: Yamaha 55HP
Join Date: Jan 2013
Posts: 448
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Very rare problem on a Yamaha.
1) Find out if it is the control box or engine. Disconnect the control box and Hotwire the engine by touching the bullet on the brown wire on the start solenoid to the incoming positive cable from the battery. This will spin the engine while you check for spark. If it sparks it is likely the kill switch, start in gear prevention switch, ignition switch or the loom itself.
2) if it does not spark on all 4 after doing the above, it would be unusual but likely to be the CDI.
3) if it fails to spark on a single lead, I would change out the coil.
Let me know how you get on.
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02 November 2014, 15:02
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#5
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Member
Country: UK - England
Town: Leeds
Make: Valiant 450
Length: 4m +
Engine: Yamaha 55HP
Join Date: Jan 2013
Posts: 448
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Thinking again. Don't worry about the start in gear prevention switch. It cuts the brown wire so your engine would not turn if there was something up with it. My money would be on a broken loom wire or the other control box switches.
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02 November 2014, 15:41
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#6
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Member
Country: UK - England
Town: swanage
Make: Thundercat
Length: 4m +
Engine: Tohatsu 50
Join Date: Apr 2012
Posts: 968
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Didn't think of the loom, will check it over all see what happens
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02 November 2014, 16:36
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#7
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Member
Country: USA
Town: NorCal
Boat name: SHARKY
Make: AB
Length: 4m +
Engine: Honda BF75 & BF5
Join Date: Dec 2009
Posts: 1,908
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I would recommend the repair manual for specs, and tests, along with a volt ohm meter. There should be a barrage of tests to run.
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02 November 2014, 21:04
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#8
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Member
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 70hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 4,531
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Check the continuity of all the wiring loom with a multimeter. Saves a lot of time down the line. Outboard manufacturers should use tinned wire. If it's oxidised an turned black that could be the source of your problem. Had similar issue with my Tohatsu, but it was the trim not the ignition.
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Is that with or without VAT?
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03 November 2014, 14:36
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#9
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Member
Country: UK - England
Town: swanage
Make: Thundercat
Length: 4m +
Engine: Tohatsu 50
Join Date: Apr 2012
Posts: 968
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Update-
Been fiddling with the wires and by some miracle got the plugs sparking!!
However, I try turn it over and it tries to start but doesn't quiet have the power. It will fire but only off the starter motor. (300-400rpm) it then backfires!?
Also noticed an arrow for my oil on my gauges. May have always been there just not noticed. The engine has oil and have tested the pump which works fine.
Don't think it's linked but still wonder what it means?
Ordered a fresh set of spark plugs and will carry on tommorow.
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03 November 2014, 18:50
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#10
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Member
Country: UK - England
Town: Leeds
Make: Valiant 450
Length: 4m +
Engine: Yamaha 55HP
Join Date: Jan 2013
Posts: 448
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Did you by any chance when checking the coils, remove the black and white wire from the coil itself or the CDI box. The slow turn over and backfire is classic out of sequence firing. If you replaced the black and white wires incorrectly, this word give exactly that.
Also those engines require a battery (from memory) of over 100AH or funny things happen with the tacho like the oil warnings going funny.
If you fiddled and suddenly everything worked, you must have a loose or bad connection and it will have to be found and fixed or you are RNLI fodder.
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03 November 2014, 18:51
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#11
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Member
Country: UK - England
Town: Leeds
Make: Valiant 450
Length: 4m +
Engine: Yamaha 55HP
Join Date: Jan 2013
Posts: 448
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Lastly, have you fully charged the battery??
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03 November 2014, 21:19
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#12
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Member
Country: UK - England
Town: swanage
Make: Thundercat
Length: 4m +
Engine: Tohatsu 50
Join Date: Apr 2012
Posts: 968
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I did switch the coils around so will take a closer look at them again.
Batteries fine, already tried giving it a boost with the car and made no difference
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05 November 2014, 16:02
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#13
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Member
Country: UK - England
Town: swanage
Make: Thundercat
Length: 4m +
Engine: Tohatsu 50
Join Date: Apr 2012
Posts: 968
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She lives!!!
Worked out that it was dampness in the coils stopping it sparking. Warmed them up and sprayed them with wd40 and she started sparking!
Worked out why she wasn't running properly and why it was backfiring after I got the spark back.
When I switched the coils I plugged no1&2 the wrong way round (black and white wires not wrong cylinders) I put them right and she fired up instantly!
Easy fix and something new learnt.
Cheers for the help!
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05 November 2014, 17:33
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#14
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Member
Country: UK - Scotland
Town: Fort William
Make: Ribcraft 585
Length: 5m +
Engine: Yamaha F115
Join Date: Mar 2012
Posts: 2,896
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No spark....help!!
The arrow pointing at the oil symbol means you are using the middle third of your oil res..
Never found them to be that accurate.
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There is a place on this planet for all of Gods creatures.........right next to my tatties and gravy.
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05 November 2014, 20:16
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#15
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Member
Country: UK - England
Town: swanage
Make: Thundercat
Length: 4m +
Engine: Tohatsu 50
Join Date: Apr 2012
Posts: 968
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Quote:
Originally Posted by A1an
The arrow pointing at the oil symbol means you are using the middle third of your oil res..
Never found them to be that accurate.
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That explains it! Oils about a quarter full
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05 November 2014, 21:30
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#16
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RIBnet admin team
Country: UK - England
Town: The wilds of Wiltshire
Boat name: Dominator
Make: SR5.4
Length: 7m +
Engine: Yam 85
MMSI: 235055163
Join Date: Jul 2005
Posts: 13,054
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Quote:
Originally Posted by lukewhiting
She lives!!!
Worked out that it was dampness in the coils stopping it sparking. Warmed them up and sprayed them with wd40 and she started sparking!
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Take them off and dry them somewhere warm for a few days, then give them several coats of Holts Damp Start. It should help.
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Sula
Red Mist
White Noise
