twin 35hp evinrude ??

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woodtic

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Jun 5, 2010
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11
I have a 1978 18ft starcraft holiday with twin 1978 35hp long shaft evinrudes with two persons and maybe 200lbs of gear top speed 22mph prop size 10 1/2 x 11 RPM 6700 WOT I do think they are original props from dealer when boat was set up but not sure I would like a little more speed at WOT without making boat to fast for slow trolling 2mph with one motor running or is this the best set up for this boat & motors
 
M

mpsyamaha

Petty Officer 1st Class
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Jun 8, 2007
Messages
395
Re: twin 35hp evinrude ??

you could definitely use some more pitch, but it may affect your trolling speed slightly. 6700 is a lot of rpms!
 
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woodtic

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Jun 5, 2010
Messages
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Re: twin 35hp evinrude ??

yes running them at WOT kind of scares me there screaming maybe something around 13 pitch
 
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steelespike

Supreme Mariner
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Apr 26, 2002
Messages
19,069
Re: twin 35hp evinrude ??

If my math is right I figure you should doing about 29 at 6,700 allowing 10% slip.
I don't think its possible to turn those motors up to 6,700.Unless there is some serious slip going on.It would be nice to varify your tach.
Rpm rating is 5200-5800 a 4" increase in pitch would put you at about 5,900.
It came with an 11" prop with a 13 being the biggest optional in 78.
You see my point? 22 seems a reasonable speed but not at 6,700.
 
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woodtic

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Jun 5, 2010
Messages
11
Re: twin 35hp evinrude ??

yes I see your point.only one tach works and seems to be accurate to engine sound to me. 6700rpm may not be accurate to what Iam thinking I read but for sure it read over 6k and sounded like it. this boat is new to me and didn't think much of it till looked at the owner's manual today full throttle operating range 5k to 6k I'll pay closer attention next weekend thanks for reply
 
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