engine mount science

[Don Bodemann]

I have a Yanmar 2QM20 in my Hunter 33 and I'm a little tired folks telling me it sounds like the African Queen. I'm told by Yanmar experts that the Q series engines were quite noisey to begin with. I have a new shaft and cutlass bearing and it has also been suggested that new mounts might help? This sounds like a good thing to try. Yanmar mounts are a little pricey though, and with all the industrial mounts out there as well as automotive engine mounts, I'm wondering if there might be a better alternative? Any input appreciatedDon

 

[Jim Logan]

New mounts are good, but....

Don: I'm sure the new mounts will help some, however, I'll bet (and I can't determine from the manual, but maybe someone who knows will add their knowledge) that the firing order and way the crank is designed make the QM series inherently more vibration prone. Wish it wasnt' so, since I have the QM15 and really did think of naming the boat "African Queen" when I first got it. Let us know if the mounts help much. I've found that switching from a 2 blade to a 3 blade propeller helps when under way, but the QM series is just rough, particuarly at lower rpms.

 

[steven f.]

shake, rattle and rolling

Though I have a different engine, I too have a new and much unwanted engine vibration. My engine is a Westerbeke 21a (24hp) on my 1981 H33. In the last year we replaced the cutlass, PSS dripless system and engine mounts with R