Repowering Renault with Yanmar 2GM

[morgantheship]

I am currently in the early stage of repowering my Hunter 27 with a Yanmar 2GM. I currenlty have a Renault engine and have just purchased a Yanmar 2GM. I am wondering if there are others that have already performed the same repower? If so, I am looking for advice, comments, and how too's and what to avoid suggestions. I will be sharing more as I work on the new (used) 2GM and begin to take out the Renault. My initial plan is to have both engines sitting side by side, check and alter my mounting beds and verify all mounting and alignment dimensions.

 

[Manny]

Check the location of output flange

The only advice I can offer is that on the Renault the output flange on the transmission is very low, so take a look at the new engine and measure the difference in height. Take a look to see what potential clearance problems that can cause, especially with the oil pan. You may find that you may have to cut away some of the liner in the engine compartment to get the engine low enough to mate with the prop shaft. You don't want to exceed the maximum angle that the engine was designed to run I keep threatening to re-power my 27' and all the vendors I've talked to have pretty much told me the same thing.
Good luck with this and please take a lot of pictures and post them. Alas, my re-power will probably be a bigger, newer Honda outboard

Manny

 

[tedsbeds]

Someone put a 20GM in my 1981 Hunter 27. There were problems I have with this instaallation. First you can't get to the dipstick easily, it is right next to the partition for the galley drawers. I replaced my drawers with a door and I am going to make an access hole oppisite the dip stick. 2 The engine is longer so the PO had to move the companionway steps about 12" further into the cabin and added filler pieces top and sides. Good luck

 

[morgantheship]

I would first want to clarify if you meant 20GM or 2 GM. The engines are different in that the 20GM is a longer engine overall. I hope you are incorrect but I will know for sure within the next week once I have both engines side by side. I actually received the the specifiic 2GM engine drawings from Yanmar and by the dimensions on the drawings the difference is only 2.39" longer towards the bow. With my current calculations I have over 5" before I would have to modify the companion ways steps and landing.
I sure as hell hope that I haven't miscalculated, but time will tell. I will keep you informed as to what I find once I have both engines next to one another. If all goes according to plan, I will be pulling the Renault next week with the Yanmar being delivered the following week. Both I hope happen before the snow flies....
I would appreciate everyone to continue to raise questions, etc....I hope this all turns out as it is a big undertaking (something I have never done before or even dreamed of doing before).

 

[amcmahon]

Three years ago, repowered 1984 Hunter27 from Westerbeke 10two to new Yanmar 2Ym15. First, I believe 15 hp is perfect power for 27. I reach hull speed 6.2-6.4 mph at about 2800-3000 rpm, depending on bottom condition and prop cleanliness. I live near Wilmington, NC with strong currents in river and ICW, and 15 allows good power, whereas 10 hp was too small. I question need for 20 hp on this size boat.
Installation issues: I replaced prop shaft hose (behind stuffing box) and realized that you must leave enough room foreward on stuffing box to allow access to change out flax stuffing - I didn't and now I must move engine foreward ~1 inch to change stuffing (for me annually since use engine alot in heavy currents). Due to engine mount location, had to install longer stringer on port side, also had to raise ~1 inch to allow allignment. Allignment is always tricky with poor access to stern on engine (one hand at a time), specs call for allign to within .004 inch - lots of trial and retrial.
Over all I am very happy with 2Ym15, getting ~15 mpg on fuel and very quiet. Good luck Tony