How to Prop Suzuki 140's

[linearpower]

Question:

So, I have a Mako 248, which I believe is around 5k weight wise... and I was running twin 115's with no counter rotation. I think props were pitched at like 14/21... and that ran pretty well...

Switched to a pair of used 140's counter rotators, I got an ok deal on but now I have to prop them. I could repeat the 14/21's but not sure that thats going to be correct with the increase in horsepower.... so I'm looking for suggestions on where I might start.

boat was running WOT at about 30 knots from what I recall... at about 5800 rpms... from what I can recall... I've heard thats not great but would love some input.

Thanks to all....

[snappergapper]

Reach out to Ken at Prop Gods and he can get you dialed in

[flounder]

linearpower

Here is a copy of a curve that I ran on My DF140s when I first installed them. They are on a 1978 Model 25 CC that weighs 4,600 lbs.

The wheels are SS 3 blade, 14" X 20".

Though the curve breaks at 2,500 RPM, my ears tell me she is most comfortable and efficient at 3,800 to 4,200 depending on the seas.

Running to the edge (50 miles), troll all day, and run home averages 2.8 NMPG over the years.

I think you made a good choice on the engines as long as they are good. I have 2,000 hrs on mine at this point and they are still reliable and strong. This summer I was concerned that the corrosion was eating thru the casting in one of the engines. It turned out to be nothing more than corrosion at the o-rings in the oil cooler. We replaced the corroded material, installed new O-rings and eliminated the problem.

Also, depending on the year of your new engines, you may have a steel inspection plug in the exhaust hsg that should be replaced with an aluminum plug to prevent galvanic corrosion of the hsg. If you are not familiar with this problem, let me know and I can give you more info on it.

[linearpower]

Thanks...

Checked with Ken at Prop Gods and he recommended starting with a 14 x 19 to see how that goes...

Sounded close to the 14 x 20 that was mentioned above... thought I would give those a try and see how close to 40 I could get with this old heavy boat... []

would be nice to see what this boat is capable of and hopefully we can maximize our options... as far as weight, when yards have looked at the boat they don't tend to talk about water intrusion in the Hull so the weight just seems to be the heavy boat itself.... from what I can gather...

This whole engine conundrum has been a bit of a mess so I'm hoping these new to me 140s are not to heavily abused and work out...

Thanks