Repower of I-28
We had our Volvo MD7A replaced with a Yanmar 3YM20 by a yard in Canada (Canoe Cove, near Sidney, BC). The engine cost about $7,300 CAN and the installation was quite a bit more than this but the yard replaced absolutely everything in the propulsion system - fuel tank, shaft, prop, dripless seal, hoses, water lift muffler and hose, exhaust thru-hull (now 2") and sea strainer. The only items from the original propulsion system are the Raycor primary filter (but its hoses are new) and the fuel deck fill fitting. Because the engine and fuel tank were out of the way, I also had the yard install an electric bilge pump - which turned out to be an expensive job. Install of the eninge alone probably cost about an addtional $5,000 CAN (for this install, they put the engine in place and removed it three times to get the engine bed/motor mounts/transmission aligned correctly to the new shaft, renting a crane for the job each time).
One thing I did just prior to the installation which saved much time and therefore labor expense was to install a relatively large aluminum hatch in the cockpit sole, betweent the area where the engine and fuel tank are located. This saved considerable time during this job and easily paid for itself.
Another thing my wife and I did during the install was to paint the engine compartment. Over a weekend when the engine and fuel tanks were removed, we cleaned up 32 years of oil, grease, etc. and painted the floor of the engine compartment with two coats of Interlux's Bilgekote. We also removed the original black foam souond installation (which was crumbling to dust) and painted the sides of the compartment with several coats of Silent Running's SR1000 which deadens sound equally well to the original foam, is much less expensive and thinner, giving us ca. 1" more room around the engine.
Although this was an expensive project, we use the boat for cruising several weeks as a time in realitively remote areas so we believe the more relaiable engine was worth the time and expense. The new engine has considerably more power and at max rpm (3,600) drives the boat at 6.7 knots which the old Volvo could not. At 80% power, we do just under hull speed (ca. 6.2 knots) with the Yanmar.