Thread: Re-powering
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Old 04-09-2011, 07:45 AM   #16
Larry M
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City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 7,903

A friend forwarded this to me recently from a rebuild that was done last summer (2010).* Interesting numbers.*
"Just completed (3 weeks ago) my replacement of my Perkins 4-236 with the Yanmar 4JH4-TE 75 hp. Costs to date: $13,800 (bobtail), $3800 to install with custom engine mounts to raise engine to suit centerline of shaft, $900 to fabricate exhaust riser(dry) to meet Yanmar exhaust system criteria to maintain warranty. $600 to service and install the BW tranny with 2:57 gear ratio, all this effort to be able to spin a large prop (20x18) to cruise at 6-7 kts at 2000 engine rpm. Goal of project is to reduce noise and vibration, fuel usage.

Somewhat disappointed in noise factor (note:my engine room has zero sound insulation), I expected more improvement. I'm sure I'm guilty of too high expectations. I will have to put in insulation in the larger engine room space and or an engine box.

Fuel consumption seems improved, haven't done enough testing to effectively measure though.

Boat rides 2-3" higher due to difference in weight (600#).

Considered the BETA 75 (equivalent to my Perkins 80 hp), but the Yanmar was cheaper by $2000. Rebuilding the Perkins was also considered, but for
$8-9,000 and I still have a 45 yr old engine block whose service record was not recorded, I felt my resale value of the boat with the new Yanmar was enhanced."

-- Edited by Larry M on Saturday 9th of April 2011 07:45:37 AM
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