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I got a call from a guy in La. who's looking to replace the gas engine in his 20 Shamrock keel drive.

I think some of you guys that did B20's and such used the Volvo diesel.

If you did, what model and what was your performance.

He's strapped for cash and wants to use his 1" shaft and 1:1 BW gear.

I got Steyer in mind but he wants a couple of options.

I put a 240 Yanmar in a 25 seavee replacing a big block. Was faster than the big block at cruise and did extremely well on fuel. 2800 cruise was 24kts, topped out at 3400. Had a 1:1.5 Hurth gear, 1 3/8" shaft. If I remember correctly swug a 16/19 prop. Rattled at idle but smoothed right out just above idle. Probably way more than is needed for a 20' boat with a flat run aft.
Jim

Bruce,
I have a 22 shamrock (stalker)

Yanmar 4LH-DTE 170 hp@ 3600rpm, 3 blade 15 x 17 prop.

rpm speed gph mpg
15oo 7.2 0.5 14.06
3000 20.0 4.2 4.74
3300 22.8 5.7 3.97
3600 26.5 6.33 2.44

I cruise at about 3300 =22/23 (knots) with clean bottom half loaded etc.
I know its a ZF gearbox but don't know ratio, can check tomorrow if you want.
It may pay you to check out the Shamrock site,I think its "Fish The Classic"
Whole bunch of stuff there and some very knowledgable guys.
Ian.

The estimate I got for my B-20 Bahia Mar was for a Volvo D-3 (160 hp) with the composite Ocean Master outdrive, which would not be 1:1 and is a duoprop. I didn't do it because of the $$$ necessary, but those that have spoke very highly of the performance and lack of fuel consumption. Hopefully, they'll be chiming in soon to give you real specifics. Walter

Since the 4LH is no longer available, its not an option.

Maybe the newer version is.

Bruce,
Just FYI but I am running 1 1/8 shafts with the MO236K43 which is the older model rated @ 212HP. ZF 45 1.5 ratio. I think the shafts are original. Coming up on 300 hours with the set up and so far all is well.