Yanmar engine installation,

[jim stull]

Warren generated a lot of traffic with his previous post on installing a new engine in his CD27. Therefor I’m posting what I learned in installing a Yanmar2GM20F in a 1977 CD27 hoping it may help someone who may dredge it up from the archives someday.

1. The package from Mack Boring (the US distributor) for a Yanmar 2GM20F will cost in the neighborhood of $5.5 K +/-. (2001 price)
2. The package will include both coupling halves, transmission, a very nice instrument panel, a fuel filter, and motor mounts.
3. My boat was a saltwater boat and no way could I get all the old coupling bolts out. (Working upside down jammed into the lazzerette.) I finally was forced to cut the shaft and took the old coupling out with the engine. The new shaft cost about $140 but hey..
4. The F in the Yanmar2GM20F designates the fresh water-cooled model. Go for it.
5. The Yanmar2GM20F is very, very different in shape than the old 8hp Yanmar. This makes building the engine mounting bed a big job. Not only must the new bed be designed and constructed but also a good bit of the old base must be carefully ground away to provide clearance for the new engine.
6. Buy and study the excellent Yanmar installation manual, even though you might decide to farm the job out.
7. You will read in various magazine articles and books about the “Yanmar installation jig”. These write-ups tell you to try and rent or buy this jig. I was not able to find anywhere to do this. The very helpful Yanmar dealer told me to carefully build the jig shown in the manual. This I did and found it to be indispensable. If you farm the job out make sure the pros have this jig and ask to be present when they “proof” the new engine bed for exact alignment with the jig. Getting the alignment “pretty good” was not too hard. Getting it “exact” took quite a long time.
8. I worried a lot about what I would do, if after I had epoxyed the new bolts into the bed, set the engine in place and THEN, I found that the alignment was off… Finally a friend, less thick headed than I, suggested that I set the bolts in the correct location AFTER the engine was engaged with the driveline. Since West recommended that the boltholes be drilled a good bit oversize to provide good bonding with the epoxy this worked like a charm. After the engine was in, I coated the bolts with epoxy and injected the thickened epoxy mixture into the holes. I previously had waxed the motor mount feet to prevent bonding them to the bed.
9. I had planned to use oak for the core of the new bed but the West System’s tech recommended against this wood. I finally used hard southern yellow pine. I found Home Depot stocks stair treads made from this material. Expensive but very nice stuff.
10. The old water muffler system will be too small to be ideal.
11. Yanmar says to convert to a single shifter system. This means 2 new cables and a new shifter. I purchased the shifter made by Vetus.
12 I had planned on using the PYI seal as several boats I know have fitted them with great success. I ask the Mack Boring dealer about this when I purchased the engine. They did not recommend this seal for the 2GM20F. They reported that the newer Yanmar mounts were very flexible to limit vibration transfer to the hull and that the PYI seal could leak because the seal travel was insufficient to always maintain the proper contact. I was not sure that I totally believed this so I talked with the PSS techs. The guy I talked said that it probably would not be a problem. Then he told me that if it leaked, compress the unit more than recommended! When I thought that this was not a great idea, he told me that PSS sold extra stiff engine mounts to replace the factory mounts if it was a problem. I don’t know if this would have been a problem but I used the Cape Dory recommended packing when I installed the engine so will have a little water to deal with in the bilge all the time.

12. I spent a good bit of time with Dave Gerr’s prop book, the Yanmar Manual, Mack Boring and Michigan Wheel trying to get the best prop. Ideally the installation calls for a 14” prop. No way will this fit. Michigan Wheel's computer program reluctantly agreed to a 13” prop. A Michigan Sailor 13RH12 three blade. The Yanmar manual gives a formula to determine the correct clearances for a given prop diameter. Following this I had to do a lot of ‘glass work to open up the window. About 1" had to be removed from the deadwood as well as the rudder. I know people are using this engine with the original 12” 2 blade prop but we plan to ask a lot of the rebuilt boat so did the best we could.
13. The engine projects a little bit more into the cabin than the old one. As we completely rebuilding the cabin this was not a big issue. But if one wants to retain the old cover/step unit this should be considered.



jandmstull@earthlink.net

[Warren Kaplan]

Warren generated a lot of traffic with his previous post on installing a new engine in his CD27. Therefor I’m posting what I learned in installing a Yanmar2GM20F in a 1977 CD27 hoping it may help someone who may dredge it up from the archives someday.

1. The package from Mack Boring (the US distributor) for a Yanmar 2GM20F will cost in the neighborhood of $5.5 K +/-. (2001 price)
2. The package will include both coupling halves, transmission, a very nice instrument panel, a fuel filter, and motor mounts.
3. My boat was a saltwater boat and no way could I get all the old coupling bolts out. (Working upside down jammed into the lazzerette.) I finally was forced to cut the shaft and took the old coupling out with the engine. The new shaft cost about $140 but hey..
4. The F in the Yanmar2GM20F designates the fresh water-cooled model. Go for it.
5. The Yanmar2GM20F is very, very different in shape than the old 8hp Yanmar. This makes building the engine mounting bed a big job. Not only must the new bed be designed and constructed but also a good bit of the old base must be carefully ground away to provide clearance for the new engine.
6. Buy and study the excellent Yanmar installation manual, even though you might decide to farm the job out.
7. You will read in various magazine articles and books about the “Yanmar installation jig”. These write-ups tell you to try and rent or buy this jig. I was not able to find anywhere to do this. The very helpful Yanmar dealer told me to carefully build the jig shown in the manual. This I did and found it to be indispensable. If you farm the job out make sure the pros have this jig and ask to be present when they “proof” the new engine bed for exact alignment with the jig. Getting the alignment “pretty good” was not too hard. Getting it “exact” took quite a long time.
8. I worried a lot about what I would do, if after I had epoxyed the new bolts into the bed, set the engine in place and THEN, I found that the alignment was off… Finally a friend, less thick headed than I, suggested that I set the bolts in the correct location AFTER the engine was engaged with the driveline. Since West recommended that the boltholes be drilled a good bit oversize to provide good bonding with the epoxy this worked like a charm. After the engine was in, I coated the bolts with epoxy and injected the thickened epoxy mixture into the holes. I previously had waxed the motor mount feet to prevent bonding them to the bed.
9. I had planned to use oak for the core of the new bed but the West System’s tech recommended against this wood. I finally used hard southern yellow pine. I found Home Depot stocks stair treads made from this material. Expensive but very nice stuff.
10. The old water muffler system will be too small to be ideal.
11. Yanmar says to convert to a single shifter system. This means 2 new cables and a new shifter. I purchased the shifter made by Vetus.
12 I had planned on using the PYI seal as several boats I know have fitted them with great success. I ask the Mack Boring dealer about this when I purchased the engine. They did not recommend this seal for the 2GM20F. They reported that the newer Yanmar mounts were very flexible to limit vibration transfer to the hull and that the PYI seal could leak because the seal travel was insufficient to always maintain the proper contact. I was not sure that I totally believed this so I talked with the PSS techs. The guy I talked said that it probably would not be a problem. Then he told me that if it leaked, compress the unit more than recommended! When I thought that this was not a great idea, he told me that PSS sold extra stiff engine mounts to replace the factory mounts if it was a problem. I don’t know if this would have been a problem but I used the Cape Dory recommended packing when I installed the engine so will have a little water to deal with in the bilge all the time.

12. I spent a good bit of time with Dave Gerr’s prop book, the Yanmar Manual, Mack Boring and Michigan Wheel trying to get the best prop. Ideally the installation calls for a 14” prop. No way will this fit. Michigan Wheel's computer program reluctantly agreed to a 13” prop. A Michigan Sailor 13RH12 three blade. The Yanmar manual gives a formula to determine the correct clearances for a given prop diameter. Following this I had to do a lot of ‘glass work to open up the window. About 1" had to be removed from the deadwood as well as the rudder. I know people are using this engine with the original 12” 2 blade prop but we plan to ask a lot of the rebuilt boat so did the best we could.
13. The engine projects a little bit more into the cabin than the old one. As we completely rebuilding the cabin this was not a big issue. But if one wants to retain the old cover/step unit this should be considered.

Jim,
Quite a write up. As I mentioned in my orginal post, the quote I got was 2 pages long. It included all the stringers for building the new bed. Installing the engine "temporarily" to make sure everything in the new bed and mounts are exactly where they should be, then removing the engine and doing the permanent installation of the bed, etc, and then reinstalling the engine. All that. They also came up with a 13" prop and my quote included all glass work to make the prop apeture big enough to accept a 13" prop. Everything else you mentioned and thensome was in it. This mechanic and this yard just did and installation of a 2GM20F this season on another CD27. I got to talk to the owners of that boat boat for a few minutes and they were very happy with the work done. Its a big job and I thank you for relating your experiences. It looks like my yard is quoting for the exact work that you posted.

Warren Kaplan
Sine Qua Non
CD27
Oyster Bay Harbor, NY



Setsail728@aol.com

[Paul Schultz]

Jim

Does this mean you won't be making the annual trip to FL in your 25 soon? I plan on towing down to the west coast around Port Charolette (sp) and dunking in there mid Nov. Then get warmed up a bit w/ some coastal cruising. Hopefuly we can make a mad dash to the dry tortugas for a day or 2 in between the storms. Hauling out just before thanksgiving and towing home. Any tips from an expert on what not to miss in the area?

Paul
CD27 ESCAPADE #224
Greenville, SC



mrisnow@juno.com