Prop sizing for 83 SN at Altitude |
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cspruill
Groupie Joined: October-29-2012 Location: Heber City, UT Status: Offline Points: 71 |
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Posted: June-02-2018 at 1:47am |
I moved to Utah from Indiana about a year ago. I re-jetted the carb, installed a drop in electronic ignition/ coil and changed the prop from 13X13 to 13X11. These changes made a marked improvement for slalom but at WOT I'm only turning 3,700 RPM & 36-38 mph on GPS depending on wind. The lakes I'm on are between 5-7k feet elevation. Should I try a different pitch on the prop? Any suggestions would be greatly appreciated!
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1983 Ski Nautique 2001
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Cam,
When you installed the EI conversion, did you check the timing and advance? Tell us more about the re jetting of the carb. Are the carb secondaries opening? |
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cspruill
Groupie Joined: October-29-2012 Location: Heber City, UT Status: Offline Points: 71 |
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Timing is set to 8 degrees advance on Pertronix 1582 EI. On carb, I dropped down two jet sizes from stock (don't recall the actual jet size but I can find out if that would be helpful). Plugs are a little darker than cinnamon but not close to fouled. I can hear the secondaries opening at WOT, Fuel filter is clean. Is it possible the throttle linkage is not achieving true WOT? Thanks
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1983 Ski Nautique 2001
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Jonny Quest
Grand Poobah Joined: August-20-2013 Location: Utah--via Texas Status: Offline Points: 2867 |
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What elevation are you typically boating? Heber City means that Deer Creek and Jordanelle are likely. At that elevation, you could decrease carb jet sizes by 3. Timing could be 10 degrees BTDC at altitude. Also, prop could be 1" pitch size smaller.
JQ |
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Current
2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
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cspruill
Groupie Joined: October-29-2012 Location: Heber City, UT Status: Offline Points: 71 |
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Thanks Rob! Got your PM as well. Will give you a ring!
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1983 Ski Nautique 2001
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cspruill
Groupie Joined: October-29-2012 Location: Heber City, UT Status: Offline Points: 71 |
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Well, after adjusting timing to 10 degrees BTDC and swapping out the old Federal 13X11 for a new Acme 912 13 X10.5, the boat is a rocketship! The holeshot is amazing, no more vibrations under load, RPMs are now at 4,400-4,600 at WOT @ 40mph. Thank you JQ for the tips and for getting me connected with Gary at Delta Props. Very happy with the results!
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1983 Ski Nautique 2001
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Jonny Quest
Grand Poobah Joined: August-20-2013 Location: Utah--via Texas Status: Offline Points: 2867 |
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Glad it worked out. Let’s go turn & burn soon.
JQ |
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Current
2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
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cspruill
Groupie Joined: October-29-2012 Location: Heber City, UT Status: Offline Points: 71 |
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Text me when you need a third. I'm going tomorrow morning at 6:30 at Jordanelle if you want to join me.
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1983 Ski Nautique 2001
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