Harmton
21.05.2021 11:49:13
• Make sure all propeller hardware is installed correctly. more
See full version: Suzuki 90hp, DF90A 4-Stroke Propellers
• Make sure all propeller hardware is installed correctly. more
• It is very important to refer to your engine's Owners Manual for important safety precautions when installing a propeller.
• Wide open throttle RPM, with boat on the water in forward gear under normal loading conditions, should fall within the range that is recommended by the engine manufacturer and not exceed the recommended maximum. This is important in determining a suitable propeller pitch. When in doubt, dealer assistance is suggested. here
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hey guys, new to me boat. 20' nautic star deck boat, It is 2100lbs. Normally a 115hp 2-stroke but this was rigged with a 05 Johnson 90hp 4-stroke. A DF90 of same year if what I have read and seen so far. RPM range of 4500-5500rpm. It's turning a 17p SS Powertech right now. 33mph gps at 6000rpms. Full tank fuel(30gals) and 2 adults into the wind. It was not ideal for a top end run but it's what I had to work with. It does this pretty easy. It's planing out pretty quick, IMO. I was thinking this boat was going to be a bit sluggish with a 90hp on it. I've had several F150's in the past on 21' deck boats and it felt similar. Just didn't have the longer legs up top. I'm think the target rpm with moderate load should be 5500rpm? That tells me a 19p would pick up some speed and and still have some hole shot? more
1) Performance issue you are trying to correct. Porpoising and low RPMs
2) Current prop manufacturer, model, aluminum or stainless as a minimum. Suzuki Stainless Steel
3) Current prop diameter and pitch (required). 14X18
4) Wide open throttle RPM and speed with an average load (very helpful) 5600 RPM @
Re: Propping a SeaArk 1872 Pro CC. here
I recently ordered a custom built SeaArk 1872CC with a Suzuki DF90A. Upon delivery the dealer lake tested the boat and said he was able to get 5800 RPMs out of it. I picked it up and returned home only to find I could barely get 5000 RPMs and 35 MPH out of it. The boat porpoises horribly too if you try to add even the slightest bit of trim. The numbers above were with a factory Suzuki 14X20 stainless prop. At this point I had to make a few assumptions; The dealer misread the tach and was only turning 4800, something had happened to the motor between the time he tested it and my testing the next day, or the prop changed pitch on the drive home. I went with the assumption that he had read the tach wrong since this would parallel more closely with my testing. The results would tend to indicate an over propping situation. The dealer swapped the 20p for a factory Suzuki 14X18 and things improved somewhat. I was able to get 5600 @ WOT. A 600 RPM jump from a 2" pitch change surprised me a little. Top speed went to 37 MPH. The proposing was not as severe but was still there if the trim was even touched from the fully down position. I'm still just barely into the operating range of 5500-6300 RPM. I've got a factory Suzuki 14X16 inbound (should be here today). If I see the same 600 RPM increase going from 18" to 16" that I saw going from 20" to 18" that should put me near the upper end of the operating range. I'm also starting to question the engine mounting height and will check that next time on the water. All that being said my questions are:
Does a 14X16 seem like too low of a pitch to run on a boat like this?
Should I be looking for a motor problem since the dealer claimed 5800?
Should the porpoising improve to the same degree I experienced going from the 20 to the 18?
go with the most the boat is rated for. you don't have to use it all, but nice to have when needed. out running that thunderstorm. [links]
Unless there is a big difference in the price I would go for the DF115. The only disadvantage I can see is original cost.
Re: Suzuki 90 or 115 Best for Pontoon Boat?
The price difference is only $600. I'll stay with my original choice of the 115 hp. more
There is more to that extra 25hp than just max rpm. There is a different program in the ECM and there may be differences in the valve train as well.