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Old 01 April 2010, 04:03   #1
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Country: UK - Scotland
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Twin engines not performing

Quick one for you guys with twins.

While I am rebuilding the merc I thought I try a twin Johnson setup, but I'm just not getting the performanceI was expecting.

I have two Johnsons, perfectly matched, props identical, both tuned to run at the same Vmax. I just cant seem to get the top speed I was expecting. I'll post pics later for analysis.

Help?
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Old 01 April 2010, 05:30   #2
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What size engines on what boat?
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Old 01 April 2010, 05:35   #3
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A couple of Johnson Single cylinders, Mid 70s vintage. old engines, but the were to hand.

Temporarily dropped on the humber while the merc gets rebuilt
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Old 01 April 2010, 05:39   #4
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Single cylinder, can't be much hp? How longs the Humber?
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Old 01 April 2010, 05:49   #5
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remember there were 2-pot 70 and 80 Hps kicking about back then.........

5m.
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Old 01 April 2010, 05:50   #6
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So do you know what hp they are?
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Old 01 April 2010, 05:58   #7
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Here's a pic of the setup:


(sorry, couldn't keep this going 'till 12..........)
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Old 01 April 2010, 06:04   #8
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2hp single cylinders!!! no idea why you cant get on the plane?!?!
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Old 01 April 2010, 06:20   #9
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Happy new April!

To be honest without the main engine on there I'm not sure the props would even touch the water!

Just for the record, I took that as a joke just before I started stripping the transom down and been waiting for 3 months for a suitable day to use it!

This is what was under three layers of "rescue orange", and will be the subject of a "refurb" thread in a few weeks when it's all back together.
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Old 01 April 2010, 11:09   #10
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I know where there is a 3rd one if you need it!
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