I seem to be getting more vibration through the whole boat than when my engine (Beta 38) was new. I recalled that the installation guide made special mention of making sure the studs on the flex mounts were not screwed in too far and contacting the mounting rails. This was something that the mechanic in Mexico who helped with the install did. Though he was excellent, he spoke and read no English, so I thought I'd recheck.
I found that the stud has two different thread portions. A small bit (maybe 12 MM?) screws into the flex mount top plate, then the lock nut and adjusting nuts are threaded 15MM or so. I can see no way that the stud could be run down too far. Is this old news in the installation guide, or only relevant to some engine models? It looks to me like the smaller thread is meant to bottom out, and be locked in place with the larger lower nut.
As that doesn't seem to be the problem, I may need new mounts, but I'm just wondering if I have this right...
On the small mounts, there is indeed a step down thread and these should be screwed in until they bottom out. On the large mounts which we use on engines from the 43 and up, you must be careful as the stud is straight so you could screw the height adjuster down too far if you are not careful.
If the vibration is there in neutral as well as when the engine is in gear, your vibration issue is likely to stem from a bolt or two loosening up over time or the flex mounts settling over time. I suggest that if you re-visit the engine alignment and you may just discover the problem.
If the vibration is only there in gear, I would look to your propeller or shaft zinc.
Thank you. I have an unusual installation (Pearson 36), with a V-drive and a driveshaft that contains a universal joint at the engine end (the angular tolerance is plus or minus 1/8 inch at the joint faces!!). I can easily confirm that it is within tolerance, and the vibration occurs whether in gear or not, but I can also confirm that the mounts have compressed a bit from new. What kind of life should I expect from the mounts? Will they give up sooner in a high angle installation? Because my drive shaft weight is carried by the rear mounts, It looks like they are collapsing much more than the fronts.
I actually know the 365 quite well. As you have a very heavy transmission (Velvet Drive) on the back of the engine it is adviseable to fit the rear mounts on the transmission instead of on the flywheel housing. This supports the weight better and works well.
The smaller Metalistic mounts (4"or 100mm bolt centers) work well on a level install and with a mechanical transmission and last for thousands of hours. However, on your boat the engine is at a fairly large down angle and with such a heavy transmission, it may pay to go to the larger Metalistic mounts that we use on the heavier engines from the Beta 43 and up. These have 140mm bolt centers.
I actually have a 367--came with a mechanical trans, and I replaced it with the Twindisc TMC60 when I repowered. The angle, and the flexible driveshaft may still be an issue. I will look into using the larger mounts (though that will require some mods to the rails. I already had to extend them, as the old Universal had a ridiculous footprint, with the "rear" mounts about in the center of the engine, and the gear totally unsupported.
