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23 May 2015, 11:55
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#1
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Member
Country: UK - England
Town: Widnes
Boat name: FROG
Make: Zodiac
Length: 3m +
Engine: Outboard 6hp
Join Date: Oct 2011
Posts: 234
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Rev counter
Hi all. Can anyone send me a link to a rev counter to buy as I want to check out my engine. 8hp Mariner 8b. I have looked on ebay and can't find a test one.
Thank you
Andy
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Always FROG
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23 May 2015, 13:47
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#2
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Member
Country: UK - England
Town: Bristol
Boat name: Salty Cheeks
Make: Honwave
Length: 3m +
Engine: 20hp 2stroke Mariner
Join Date: Mar 2014
Posts: 485
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Not sure how to link but Digital Tach Hour Metre,should come straight up.
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23 May 2015, 18:46
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#3
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Member
Country: UK - England
Town: Up North and right a bit
Make: XS500/Merc340/Bic245
Length: 5m +
Engine: Mar 60/20/3.5/Hon2.3
Join Date: Sep 2013
Posts: 1,130
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23 May 2015, 20:00
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#4
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Member
Country: UK - England
Town: Widnes
Boat name: FROG
Make: Zodiac
Length: 3m +
Engine: Outboard 6hp
Join Date: Oct 2011
Posts: 234
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Thanks to you both. Liked the "better one" though.
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Always FROG
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23 May 2015, 22:00
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#5
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Member
Country: UK - England
Town: Up North and right a bit
Make: XS500/Merc340/Bic245
Length: 5m +
Engine: Mar 60/20/3.5/Hon2.3
Join Date: Sep 2013
Posts: 1,130
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Don't blame you. I have both, both work, but the better one has a much clearer display. Factor in some import tax if considering though.
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25 May 2015, 09:27
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#6
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Member
Country: UK - Scotland
Town: Isle of Lewis
Boat name: Macleod Special
Make: Mako Thundercat
Length: 4m +
Engine: Yamaha 70ces
Join Date: Jul 2010
Posts: 1,266
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29 May 2015, 04:16
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#7
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Member
Country: USA
Town: Chicago
Make: N/A
Length: no boat
Engine: N/A
Join Date: Jan 2015
Posts: 75
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I tried for a couple hours to find a spot on my Merc 15's spark plug wires that'd make my trail tech tto portable tach work. I couldn't get it to read reliably. I would get a stable reading, but then it'd just start going all over the place again. Tried switching the sensitivity as well.
Those portable tachs are nothing more than a digital display with a long wire antenna attached to them, anything electrical going on in the motor will interfere. I found that even if I somehow managed to get a somewhat reliable reading, placing the cowl back on the motor ruined it. I resigned to the fact that messing around with it any further was a fool's errand, especially since the cowl seems to be like reflecting the interfering signals back inwards (which the trail tech tach would pick up).
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29 May 2015, 10:04
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#8
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Member
Country: UK - England
Town: Bristol
Boat name: Salty Cheeks
Make: Honwave
Length: 3m +
Engine: 20hp 2stroke Mariner
Join Date: Mar 2014
Posts: 485
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Quote:
Originally Posted by kestrel452
I tried for a couple hours to find a spot on my Merc 15's spark plug wires that'd make my trail tech tto portable tach work. I couldn't get it to read reliably. I would get a stable reading, but then it'd just start going all over the place again. Tried switching the sensitivity as well.
Those portable tachs are nothing more than a digital display with a long wire antenna attached to them, anything electrical going on in the motor will interfere. I found that even if I somehow managed to get a somewhat reliable reading, placing the cowl back on the motor ruined it. I resigned to the fact that messing around with it any further was a fool's errand, especially since the cowl seems to be like reflecting the interfering signals back inwards (which the trail tech tach would pick up).
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Hi
What about once connected to the HT lead, try covering the rest of the lead with insulation tape just a thought.Also have the lead running directly outside of the engine cowl.
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29 May 2015, 11:26
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#9
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Member
Country: UK - England
Town: Sussex
Boat name: Bombard
Make: Aerotec 380
Length: 3m +
Engine: Mercury Mariner 15hp
Join Date: Jul 2010
Posts: 3,499
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Quote:
Originally Posted by kestrel452
I tried for a couple hours to find a spot on my Merc 15's spark plug wires that'd make my trail tech tto portable tach work. I couldn't get it to read reliably. I would get a stable reading, but then it'd just start going all over the place again. Tried switching the sensitivity as well.
Those portable tachs are nothing more than a digital display with a long wire antenna attached to them, anything electrical going on in the motor will interfere. I found that even if I somehow managed to get a somewhat reliable reading, placing the cowl back on the motor ruined it. I resigned to the fact that messing around with it any further was a fool's errand, especially since the cowl seems to be like reflecting the interfering signals back inwards (which the trail tech tach would pick up).
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I found the opposite on my Merc 15, worked perfectly (£10 Chinese job) - just wound the wire around the HT lead next to the plug, fed the wire out under the cowl seal and worked great.
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29 May 2015, 11:33
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#10
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Member
Country: UK - England
Town: Bristol
Boat name: Salty Cheeks
Make: Honwave
Length: 3m +
Engine: 20hp 2stroke Mariner
Join Date: Mar 2014
Posts: 485
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Same with mine,just the display is angle sensitive.
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29 May 2015, 14:36
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#11
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Member
Country: UK - Scotland
Town: Isle of Lewis
Boat name: Macleod Special
Make: Mako Thundercat
Length: 4m +
Engine: Yamaha 70ces
Join Date: Jul 2010
Posts: 1,266
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I've not had any problems like that with the tachs. Just be careful of how many times you wrap the wire around the HT lead, once should do, maybe twice. If you put too many it will break (not sure why, thats the reply I got from tinytach!)
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31 May 2015, 06:24
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#12
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Member
Country: UK - Scotland
Town: Denny
Boat name: Highland Bluewater
Length: 6m +
Join Date: Mar 2013
Posts: 1,647
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I've got one of Chipko's "cheep ones" on my 6hp merc and it works perfectly. It's fitted under the cowl because I only really wanted it for "hours". The wire was cut short, wrapped round the HT lead 4 or 5 times and taped to it. Strangely it had to be set to "firing twice per revolution" to get the correct reading (1300-6000rpm) on a single cylinder 4 stroke. Didn't make sense to me but........if it ain't broke, don't fix it.
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01 June 2015, 11:51
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#13
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Member
Country: UK - Scotland
Town: Isle of Lewis
Boat name: Macleod Special
Make: Mako Thundercat
Length: 4m +
Engine: Yamaha 70ces
Join Date: Jul 2010
Posts: 1,266
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that could be down to the number of wraps around the HT lead as well
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02 June 2015, 18:22
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#14
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Member
Country: UK - Scotland
Town: Denny
Boat name: Highland Bluewater
Length: 6m +
Join Date: Mar 2013
Posts: 1,647
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Quote:
Originally Posted by Roflhat
that could be down to the number of wraps around the HT lead as well
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Wouldn't have though so. The number of turns will only vary the amplitude of the induced pulse and the digital tach won't use a "diode charge pump" type input because it has to be able to cope with different HT voltages from Kettering to electronic.... about 28KV to 40KV+. To be honest I didn't really give it much more thought, the 1300 idle speed was bang on and the rev limiter cut in at 6100 so that was good enough for me. I know some ignition systems fire redundantly at the end of the exhaust stroke just for simplicity but I'm only really looking to record hours so it had as much time spent on it as I was going to give it.
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03 June 2015, 09:37
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#15
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Member
Country: UK - Scotland
Town: Isle of Lewis
Boat name: Macleod Special
Make: Mako Thundercat
Length: 4m +
Engine: Yamaha 70ces
Join Date: Jul 2010
Posts: 1,266
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sounds like you know much more about than I do! haha
Think somebody on the thundercat forum mentioned the number of wraps could have an effect
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