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Post by lafromla1 on Jul 25, 2015 14:29:31 GMT -6
my sv2100, with a Johnson 140, came with a 13 7/8 x 19 prop. I am thinking of dropping it down to a 17 to get some more push and get on plane faster. I am not too concerned about overall top speed as I rarely ever get there anyway.
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Post by stripersniper on Jan 3, 2016 17:11:43 GMT -6
I have a sv 195 with ttop 30 gall baittank etc. Has a 115 merc 4 stroke. Went out with a few buddies in the last few months. One was a skiff and other starts with a t and is plastic I think. Both had 50 gall attacks and ttops. One had a suzuki 115 other yam 115. Both jumped out of the hole and went 40mph. Mine won't get out of hole with more than 3 people and only goes 32mph. My boat came with a 19 prop and was used so not sure what factory prop was. Remember around 5500 wot. What can I do?
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Post by Juan on Jan 3, 2016 17:42:33 GMT -6
Max RPM at (WOT): 5800-6400 so if you're turning 5500, I'm guessing you probably need to run a 13" pitch prop to get to the rpms you should be turning... here's a link to a prop calculator... you can enter the info and it will give you a recommended prop based on your boat's current performance Prop Selector
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Post by gnrphil on Jan 3, 2016 19:14:14 GMT -6
You have 33% slip there which is terrible and you need to see another 700rpm in my opinion, I think you have a lot more going on than just prop pitch (although a 19 is way to much). 1. Make sure your motor is running right and healthy, do a compression check. 2. Check your motor height, ensure the AV plate is just above the water or being splashed when on plane. Another check is to measure with a straight edge from the bottom of the hull, AV plate should be level with or an inch or two above the hull bottom.
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Post by stripersniper on Jan 5, 2016 6:06:56 GMT -6
Ok, I think both the other boats had lower pitch but dosent that lower top speed?
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Post by stripersniper on Jan 5, 2016 6:15:02 GMT -6
Pretty sure running is ok, I go out almost every weekend and had bot 3 years.
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Post by gnrphil on Jan 5, 2016 8:05:19 GMT -6
Ok, I think both the other boats had lower pitch but dosent that lower top speed? No, a high pitch prop requires more effort to turn. If your engine can't turn said prop to max rpm your not getting full power and thus can't get top speed. I ran a 19 on my 200 and it was slower than the 17 and I could only get 5000 rpm. It's a fine balance and also different hulls will be quicker than others, and different manufacture props will be different. Different cupping and rake angles will effect how a prop performs. I had a 15 pitch prop and switched to a 17, saw no difference in speed or rpm !!!, come to find out the Stihleto 15 has aggressive cupping and performs like a 17. I strongly suggest you contact Ken at Prop Gods, He's the prop guy. www.propgods.com/Content2/Default.aspx
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Post by gnrphil on Jan 5, 2016 10:14:50 GMT -6
Cheapest cure is getting boat set up properly with engine height before playing with props. My two cents. Absolutely emthup
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Post by Juan on Jan 5, 2016 16:36:46 GMT -6
Cheapest cure is getting boat set up properly with engine height before playing with props. My two cents. Absolutely emthup X2 If your engine isn't set up right, it might be hard to select the right prop and without the right prop, your boat won't perform as it should.. It's a mixture of both.
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Post by stripersniper on Jan 7, 2016 5:35:47 GMT -6
I've been running it as is for several years and it's always bugged me about top speed. I called the previous owner about it because he said he had it up Near 40mph. He said he played around with props and that one worked best so I haven't thought much about it. I just took a pic of motor, not sure you can see much but it looks like it's been raised. Issue with prop is I don't have any prop shops within 1hr drive and don't have the money to buy different ones just to try.
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Post by Juan on Jan 7, 2016 7:49:24 GMT -6
looks like it's been raised. It has.. It's as high as it will go without adding a jack plate but that doesn't mean that it's too high. As already mentioned, the motor height should be where the cavitation plate on the motor's foot is at or just below the hull and you should use a prop that allows your motor to run at the factory recommended WOT (wide open) RPMS when fully trimmed. Only then will you get the best performance and fuel consumption.
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Post by gnrphil on Jan 7, 2016 21:23:06 GMT -6
Well it won't go any higher, How do you have it trimmed for hole shot and WOT ?
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Post by stripersniper on Jan 8, 2016 5:05:51 GMT -6
Trim it down to take off then trim up as far as I can until front starts bouncing.
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