Which prop ? Zuke DF250 on a Sceptre
 

Im running a suzuki 3x16x18.5 prop and im only getting 5450 rpm wot with light load and engine trimmed up.Recommended rpms is 5500 to 6100.My cav plate is about 1/2" above the keel.
I have a full canvas enclosure and bottom paint ,motor mounted on transom.I heard that Suzuki props are usually a higher pitch than what is stamped on them.
Thinking I should go to a 16x17 and raise the engine one hole.

If anyone is running the same set up I would love to see your numbers and what prop your using.
Thanks in advance

I have a little different set up, but on my 23WA w/ bracket, DF250, 3X16X23 Suzuki prop (came with the motor), 5600 rpm wot, light load, 48 mph.

Before I tried it, I thought the 23 pitch was going to be too much, but the rpm's are right in the range. So I thought the stamp was wrong, but this works out to 10% slip, so it probably about right.

I hope this helps.

Lloyd

Those Suzukis turn bigger props than most other outboards. They are gear differently. 23p sounds about right. My buddy has a 25' Contender with a bracket and Suzuki 300. 19p prop came with the motor, Ken at Propgods.com recommended a 23p for his application. Hit Ken at Propgods.com. He will recommend you a prop based off your specific application.

Riptide - Start buy raising the motor 1 bolt hole. Then mess with pitch. I'll bet you pick up 200/300 RPM's just by raising the motor.

Well I have been working on this engine all day.
Raised the motor one bolt hole.
New water pump
Oil change and new spark plugs.
I adjusted the throttle cables because they didn't open the throttle completely all the way.
Maybe that was my problem. Going to put her back in the water tomorrow if its not storming out and hopefully I'll be at my correct rpms.
Thanks for the replies,stay tuned.

I got her back in the water today between thunder storms and here are the results.
5650rpm wot was all I could get on flat water.I did gain 200 rpm by raising the motor one hole but I would like to be in the upper rpm range around 5800 to 6000 because I run offshore often heavily loaded.

I feel like something isn't right if you guys are running 21 & 23 inch props and getting those numbers.
I guess I should checkout Prop Gods and see what they say.
Thanks ,Jerry

It does sound funny, but you really aren't very high on the motor only going from 1/2 to 1 hole up. I would also call Ken as application doesn't help

What max speed are you getting?

44.9 mph on flat water light load trimmed up

With a full canvas enclosure and bottom paint, I'd say 44.9mph isn't bad.

That isn't bad at all. As a comparison, my father's '82 Sceptre ran 40mph/35 knots at it's best with a full enclosure and bottom paint, and that was with both a '89 Evinrude 225 looper and '96 Yamaha 225 SWS.

I have a 23 Tsunami, full top with a df 250 on a 12 inch set back aluminum bracket. I'm running a 20x16 suzuki 3 blade and getting 40 knots at 6100 with an offshore dive load and a couple of buddies. Can you trim the motor and gain speed and rpm? If so keep moving her up. This photo was before I changed props.

5650 was all I could squeeze out of her trimed up w/light load.There is only one hole left to go up.
I bought a 16x17 prop but didnt get to try it out yet.I'll raise her one more hole and see what happens before I change props. At least I have a spare now.

http://img.photobucket.com/albums/v6...0515111755.jpg

That is a 30 inch motor.... right? also, are you running a 4 or a 3 blade prop?

Yes 30 inch motor on a 30 inch new transom. Running a 3 blade suzuki prop.
6100 rpm at 40knots with a 20 inch prop
are great numbers.
Why did you put a jack plate on your Tsunami ? Was the motor on the transom at one point?

The transom was built for 25 inch motors so the plate not only made up the difference, it gave me some cleaner water to run in and left me lots of room to walk in from the dive ladder. I'm almost wondering if you should do a compression check. I had power issues with my motor due to carbon build up on the valves. (Crappy ethynol gas) I ran a bunch of ring free through it and have been running maintainance levels of Lucas and have regained full, like new compression and power.

Another problem may be that someone changed the pitch of that prop. I have run into that with other boats and it really through me for a loop. It sounds like your getting close to the expected speed but the rpms are off. Somethings up but I don't think its a big issue.

I will try some ring-free but I mostly use Val-tech fuel at my marina that claims to have all the additives for ethanol in it.The prop came from the dealer with the motor so I don't think the pitch was changed.I should have my new prop by this weekend.If I loose a little top end that's fine as long as I'm in the upper rpm range Ill be happy.Thanks for your help.