A27 Original Prop Size

[boater_mike]

I'm pretty sure i'm over-propped. But before I haul the boat or hire a diver to look at things, I'd like to find out what was originally installed with the Peugeot 4D61.

The current "suspected over-propped" prop, came with the boat, and it's rather annoying not being able exercise the engine as it should be - I'm stuck at 2200 rpm, and anything above, I start to overheat and get black sooty water from the exhaust. It looks like the current prop is tuned with the published "power curves" for the ancient Peugeot - the 2200 rpm giving max torque.

After looking through the forums, i see a couple different sizes: 15x11 and 15x13 (I think), and I was wondering if there were other sizes.

Backstory: I get full RPMs at the dock in neutral, and I'm also looking at the exhaust elbow to make sure it's clean. Already checked throttle linkage, so i'm pretty sure it's the prop.

Any information would be appreciated.

-Mike

[stmbtwle]

Lucky you! I think the original prop size is in the vicinity of 18x14. While I can't confirm that it does seem to be a common size.
What engine do you have NOW and what RPM is it supposed to run at? Many boats have been repowered and unless they were repropped at the same time there's a good chance it's not a perfect match.
In your case I can see three options, repitch, cut down the prop, or buy a new one. If you're lucky you may find a used one. A new prop won't be cheap.

Probably what you need to do is visit a full-service prop shop, along with all the data you can collect, and your old prop. They should be able to determine exactly what you have and can explain the best options. You might want to wait till fall.

[tego]

The18x14 is the prop size for the Nissan LD28 on our 27FC. I believe the older Peugeot 4D61 was a 15" but I've heard od several pitches so I can't help you there. Ben

[boater_mike]

What engine do you have NOW and what RPM is it supposed to run at?

I have the old Peugeot and I think it should max out at 9 knts, and approx 4000 rpm. I would likely never go that high, but cruising around 6-7 kts would be good knowing i have a bit more power in reserve.

As it is currently, I'm maxed at 2200 rpm (roughly) and 7 knots. I have reached 10kts downhill with a stiff wind at my back. It's a bit squirrelly trying to control in those conditions.

I think Ben is right, the prop should be closer to 15 inch...just curious what a proper pitch would be.

-Mike