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'98 S115TLRW
I recently cleaned and replaced carb kits, replaced fuel pump, fuel filter, and fuel hose. Now that has been checked off my maintenance list it's time to address dialing in the correct propeller.
When I purchased boat/motor from previous owner it came with a 21" pitch SS prop. The dry weight of the hull is 1100 lbs, 17' mod-vee bay boat. Running at WOT, 1/4 tank of fuel, and no other necessary weight, i'm turning 4400 rpms.
For the sake of not spinning off onto other related topics, see above for the low rpms being caused by fuel issue. The height of the motor is also correct.
Using Yam's prop selector webpage, the prop pitch range recommended is between 13" and 15" (confirming my assumption the 21" pitch currently on motor is over-propped). If you use the rule of thumb 150 ± 50 rpms for every inch of pitch:
[Motor spec range is 4500-5500@WOT]
13" pitch puts my WOT rpm range at 5200-6000
15" pitch puts my WOT rpm range at 5000-5600
I've read a few threads for similar topics. Rodbolt suggests using a test wheel to confirm a prop issue, rule out a motor or rigging issue. Problem is a test wheel seems hard to come by, at least in my area. The 4 nearby yam dealers do not have one (or at least not for public use), neither does the yam mechanic I personally know.
Of the above two choices I'd go with the 15" pitch because of what the rpms would be at WOT. So before investing a bunch of $$$ on a prop I'd like your thoughts or suggestions in choosing the correct pitch. It may only be a pitch difference of 2" between the above props, but 2" could translate into a 200-400 rpm difference.
I recently cleaned and replaced carb kits, replaced fuel pump, fuel filter, and fuel hose. Now that has been checked off my maintenance list it's time to address dialing in the correct propeller.
When I purchased boat/motor from previous owner it came with a 21" pitch SS prop. The dry weight of the hull is 1100 lbs, 17' mod-vee bay boat. Running at WOT, 1/4 tank of fuel, and no other necessary weight, i'm turning 4400 rpms.
For the sake of not spinning off onto other related topics, see above for the low rpms being caused by fuel issue. The height of the motor is also correct.
Using Yam's prop selector webpage, the prop pitch range recommended is between 13" and 15" (confirming my assumption the 21" pitch currently on motor is over-propped). If you use the rule of thumb 150 ± 50 rpms for every inch of pitch:
[Motor spec range is 4500-5500@WOT]
13" pitch puts my WOT rpm range at 5200-6000
15" pitch puts my WOT rpm range at 5000-5600
I've read a few threads for similar topics. Rodbolt suggests using a test wheel to confirm a prop issue, rule out a motor or rigging issue. Problem is a test wheel seems hard to come by, at least in my area. The 4 nearby yam dealers do not have one (or at least not for public use), neither does the yam mechanic I personally know.
Of the above two choices I'd go with the 15" pitch because of what the rpms would be at WOT. So before investing a bunch of $$$ on a prop I'd like your thoughts or suggestions in choosing the correct pitch. It may only be a pitch difference of 2" between the above props, but 2" could translate into a 200-400 rpm difference.
) and the aluminum prop doesn't hold up well at all. I'd constantly be filing the leading edge as they get torn up easily.
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