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11 April 2016, 21:14
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#1
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Member
Country: UK - England
Town: Bournemouth
Boat name: Lucky Heather 3
Make: Spearfish
Length: 5m +
Engine: Small!
Join Date: Mar 2015
Posts: 98
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So, what have I blown?????
Ok, finally got the rebuild finished on my yam mariner 689 30hp 2 stroke 2 cylinder 1992 autolube and super stoked at how it looked, I decided to run in it today so, stuck in a tank, added 50.1 in the fuel as a precaution with the autolube checked and ready to go. I didn't have the remotes so read up on how to loop the plug (black/yellow pin 1 to black pin 4 and yellow/red pin 7 to red pin 8) to bypass the kill switch.
Anyway, the engine started first pull but.... after running for about 15min it suddenly died barrrrrrrrrrrrrrrr , so I though the worse that it had a heat seize which it didn't. So checked everything, compression good, fuel good, all wiring, fuse etc missing a spark though. So went to the boat, removed the remotes, plugged the engine in with the electric start and it turns over but still no spark.......so, what have I fried?
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11 April 2016, 21:56
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#2
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Member
Country: UK - England
Length: 3m +
Join Date: Sep 2008
Posts: 2,767
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Master Fuse?
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11 April 2016, 22:03
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#3
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Member
Country: UK - England
Town: Bournemouth
Boat name: Lucky Heather 3
Make: Spearfish
Length: 5m +
Engine: Small!
Join Date: Mar 2015
Posts: 98
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Quote:
Originally Posted by ShinyShoe
Master Fuse?
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nope, fuse all good
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11 April 2016, 22:17
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#4
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RIBnet admin team
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,632
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Just one spark that's not firing?
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11 April 2016, 22:33
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#5
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Member
Country: UK - England
Town: Bournemouth
Boat name: Lucky Heather 3
Make: Spearfish
Length: 5m +
Engine: Small!
Join Date: Mar 2015
Posts: 98
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Quote:
Originally Posted by Poly
Just one spark that's not firing?
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no both, even removed the caps (new screw on champion type) to see if the wires sparked but nothing. Could it be the CDI?
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11 April 2016, 22:59
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#6
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RIBnet admin team
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,632
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Quote:
Originally Posted by papajoe
no both, even removed the caps (new screw on champion type) to see if the wires sparked but nothing. Could it be the CDI?
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Well it could be, but it would be rotten luck to rebuild an engine and have something major die 20 minutes later. Someone else ( http://www.rib.net/forum/f50/maiden-...cue-71616.html) had a very similar issue recently. My money would be on a wiring issue (perhaps something came loose, wore through, got hot, shorted out).
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11 April 2016, 23:31
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#7
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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: 4,650
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Outboard kill cord?
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Is that with or without VAT?
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12 April 2016, 04:04
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#8
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Member
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
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50:1 plus auto-lube? Change plugs and see what happens.
jky
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12 April 2016, 06:22
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#9
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Member
Country: UK - Wales
Town: abergele
Boat name: all mine
Make: ribtec 3m
Length: 3m +
Engine: tohatsu 9.8 hp 2st
Join Date: Sep 2012
Posts: 292
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Check the coils they could be breaking down once warm could check with a muti meter
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12 April 2016, 06:58
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#10
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Member
Country: UK - England
Town: teesside
Boat name: magic
Make: humber 5.5
Length: 5m +
Engine: mariner 115
MMSI: 232012453
Join Date: Apr 2014
Posts: 1,558
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Quote:
Originally Posted by jyasaki
50:1 plus auto-lube? Change plugs and see what happens.
jky
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and run it on just petrol cos your weakening the afr putting oil in
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12 April 2016, 08:26
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#11
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RIBnet admin team
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,632
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Quote:
Originally Posted by beerbelly
and run it on just petrol cos your weakening the afr putting oil in
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He's just rebuilt it. Normal run in procedure is 50:1 plus the autolube for the first tank.
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12 April 2016, 09:43
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#12
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Member
Country: UK - England
Town: Bournemouth
Boat name: Lucky Heather 3
Make: Spearfish
Length: 5m +
Engine: Small!
Join Date: Mar 2015
Posts: 98
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Plugs are new and clean, adding oil as it's a rebore with new pistons rings etc and standard practice for rebuild. So thinking stator coil, ignition coil or cdi?
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12 April 2016, 17:50
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#13
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Member
Country: UK - England
Town: bicester
Length: no boat
Engine: outboard only
Join Date: Feb 2009
Posts: 913
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no spark at the s/plugs check all earth connections are clean and tight, then check other connections, if ok check the stator and trigger voltage with a multimeter,then the switch box working your way from stator to s/plugs.
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12 April 2016, 18:02
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#14
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Member
Country: UK - England
Town: Midlands
Make: Ribeye 600
Length: 6m +
Engine: Yamaha F115
Join Date: Dec 2010
Posts: 204
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Most likely an earth or coil issue.
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12 April 2016, 20:23
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#15
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Member
Country: UK - England
Town: teesside
Boat name: magic
Make: humber 5.5
Length: 5m +
Engine: mariner 115
MMSI: 232012453
Join Date: Apr 2014
Posts: 1,558
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Quote:
Originally Posted by Poly
He's just rebuilt it. Normal run in procedure is 50:1 plus the autolube for the first tank.
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with autolube jet sizes adding oil to the fuel tank will reduce the amount of petrol in the mix the air volume is fixed with the throttle opening the jets can only flow so much fluid so by adding oil you will lubricate more but be running a weaker air fuel mixture which we all know isn't good burns pistons ect, surely a better idea would be to increase the amount of oil the oil pump sends into the inlet . or am I overthinking this I grew up on 2 stroke mopeds and kh 250,s and had a few seizures in my kack handed tuning attempts
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12 April 2016, 20:28
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#16
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Member
Country: UK - England
Town: warrington
Make: Honwave T32
Length: 3m +
Engine: Mercury 15 2 stroke
Join Date: Oct 2011
Posts: 523
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Quote:
Originally Posted by Poly
Well it could be, but it would be rotten luck to rebuild an engine and have something major die 20 minutes later. Someone else ( http://www.rib.net/forum/f50/maiden-...cue-71616.html) had a very similar issue recently. My money would be on a wiring issue (perhaps something came loose, wore through, got hot, shorted out).
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I'm still struggling to diagnose this issue, although I haven't had much time as I was away last weekend
I have purchased a multi meter, I'm now trying to figure out all the various settings before I can test ignition components, I can't say I'm particularly confident in my electrical diagnostic abilities though :-)
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12 April 2016, 20:38
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#17
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Member
Country: UK - England
Town: Dorset
Boat name: Seabadger 2
Make: Delta / Ribcraft 6.8
Length: 7m +
Engine: Various
MMSI: -
Join Date: May 2010
Posts: 743
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Just checking the obvious, but you haven't mentioned it. Have you run out of fuel or developed a fuel issue?
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12 April 2016, 20:40
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#18
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Member
Country: UK - England
Town: Dorset
Boat name: Seabadger 2
Make: Delta / Ribcraft 6.8
Length: 7m +
Engine: Various
MMSI: -
Join Date: May 2010
Posts: 743
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Ignore that. Didnt RTFQ. Apologies.
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12 April 2016, 21:15
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#19
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Member
Country: UK - England
Town: Bournemouth
Boat name: Lucky Heather 3
Make: Spearfish
Length: 5m +
Engine: Small!
Join Date: Mar 2015
Posts: 98
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Gone through it all and think it all fingers are pointing to the coil which now thinking aback would explain the random knocks here and there before I stripped the engine as the pack started to fail
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12 April 2016, 22:40
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#20
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Member
Country: UK - England
Town: Midlands
Make: Ribeye 600
Length: 6m +
Engine: Yamaha F115
Join Date: Dec 2010
Posts: 204
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Quote:
Originally Posted by beerbelly
with autolube jet sizes adding oil to the fuel tank will reduce the amount of petrol in the mix the air volume is fixed with the throttle opening the jets can only flow so much fluid so by adding oil you will lubricate more but be running a weaker air fuel mixture which we all know isn't good burns pistons ect, surely a better idea would be to increase the amount of oil the oil pump sends into the inlet . or am I overthinking this I grew up on 2 stroke mopeds and kh 250,s and had a few seizures in my kack handed tuning attempts
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Yeah that would explain the lack of spark?
Modern synthetic oils burn as part of the combustion process, old mineral oils didn't..
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