Prop or injection pump or?

[Burton]

I called Mack Boring (The Yanmar distributor) and had a very helpful service person give me some wisdom on this. I had called to see if I would be damaging the engine to run with this situation.

As suggested previously, I needed the numbers off the prop. The numbers are 17 RH 16. The representative suggested that I connect with others with the same boat and engine and see what they are successfully running.

Albin 25 Deluxe, Yanmar 3JH3E, 40 HP, max rpm 3800. Currently will not go above 2850 RPM, and 9.5 kn.

The representative suggested dealing with this issue sooner than later, that being over propped will shorten the life of the engine.

By the way, you can use a GoPro with Wi-Fi connection to look under your boat. You simply have to use a piece of coaxial cable— I made mine about 12 feet long—and make an antenna for it as the WiFi won’t work underwater without it. Strip the shield down to expose 2.4 inches (6mm) center conductor on the ends, and tape the antenna to the waterproof housing near the buttons. Hold the other end antenna alongside your phone. Extend the GoPro on a boat hook or fishing pole. By the way, this didn’t work for us as there was too much crud on the propeller—had to dive and use a wire brush.

[WillieC]

" Dont bring the entire contents of your garage and kitchen on board. Both will rob you of speed."

Whoa, whoa, whoa...The aft cabin has been divided into two sections: Costco starboard and West Maroon port. Everybody calm down.

I have a bit of experience of coking up my engine. And de-coking kits are available for the old Volvo Pentas. Seems like I wasn't the first one. I am running a 17-13 on the original MD17C and I was trying to wring all the mojo our of it after a full top end rebuild. I mojoed it too far and lost most of my compression as the coke was holding valves open. The problem was my injection pump adjustment and completely my fault. We'll see if I corrected it through the summer.

[honza]

What is the gear ratio? You want to know the RPM on the prop shaft.

[Burton]

As a follow up, all of us might be wise to pick up spare used props ahead of time of need. Recently there was a used Albin 25 prop on eBay for $125. I think it was a 16/12...?

I got one quote for a new prop at $650. That’s just the prop. The re-pitch of our 17/16 to 17/14 is going to be $250. Perhaps a prop cage is a good idea for more than avoiding lobster pot warp.

[WillieC]

Picking up spare props is easier said than done. Pitch, bore, hand, diameter, metric or SAE...I looked hard, couldn't shake one loose, broke down and bought a brand new one. Bought a spare engine from another A25 owner who wanted full new price for a used prop that would only belong to the boat with our old engines. I let him keep it.

Another A25 owner went through a similar engine swap and let me know he had a spare shaft that has the same metric taper I have. Free. Oh, and a prop with 14 pitch for a couple hunnert bucks. I snapped it up. It's all about timing, good luck and the kindness of strangers.

16/12 sounds like an AD21 prop. $650 sounds about right for new. If you can re-pitch your 17/16 and it is the right number, go for it. There is the added issue of cup, which I know nothing about. (You A28 guys need to remember we only hit 6 or 7 knots...) Ask your prop guy. Others may weigh in. Dkirsop I think cupped his on the AD21. Way sharper than I am.

Sorry about the lobster pot. We have plenty of crab pots in the northern Sound here. Keep a sharp lookout. I have a horror story from a neighbor crewing on a new to owner 50 or 60 foot boat. In strange water and not paying attention to much of anything...Thwack! Schwang!!

Didn't sink it, but easily could have. Took a chunk out of one of the transmissions. The rudder stopped the shaft from exiting the boat which made for a slow leak. Allegedly a four week repair time and how many boat bucks you got? The piles were right there on the chart. Love my A25, plastic shaft saver, plotter, charts, and Starfleet Commander who freaks when the chart goes from white to blue. Towing insurance is good, too.

[Dieselram94]

Burton, what’s the name of your boat?

[dkirsop]

Having my prop cupped increased the efficiency but does not result in an overall increase in top speed. I now find I can plan my cruise for an average speed of 6 knots at 1600rpm whereas before it was around 5 knots at this setting. At 2100 RPM top speed remains 7 knots but all conversation is lost and fuel consumption rises considerably, same as before. So...my fuel consumption has decreased slightly at my cruising speed of 6 knots and it is about 68 dB in the wheelhouse, an improvement I am happy with as there is less wear and tear on both the engine and the pilot.