Check your Idle RPM

[TBOT422]

I've read with great interest many of the posts on this forum, combined with my limited experience with the M35B. Many of the problems that seem to be associated with this engine appear to be resulting from or related to excessive vibration - broken fuel filter and HE mounts, failed pre-heat solenoids, damper noise, etc.

The 'recommended' range is supposed to be 800-1000 RPM, but Westerbeke recommends setting it to the "high side" of this range and warns to be sure to set the RPM with a "known good hand help photoelectric style tachometer before the ships meter should be trusted".

I didn't have a "good photoelectric" tachometer available, but found that an increase of about 50-100 RPM greatly reduced the engine vibration at idle. After adjusting, my helm mounted tach, now shows just under 1100 RPM at idle out of gear and about 1050 in gear, and I no longer have a noticeable vibration at my feet when standing at the helm. Hopefully, I will also have fewer component failures in the future.

I would suggest that everyone observe the vibration in this engine at idle and rectify it as soon as possible to prevent future damage to all sorts of components. There is most likely enough slack in throttle linkage to get 50-100 RPM by simply pushing on the linkage at the engine while observing the amount of vibration. If the vibration seems to smooth out significantly, it may be a good idea to make a permanent adjustment, or determine why there is more vibration than normal. Possiblities include: worn or bottomed out engine mounts, mis-firing, etc. But, as Westerbeke responded to me in a recent correspondance: "It makes good sense to avoid the RPM ranges which make the engine vibrate whenever possible." So crawl down there and take a look when you're running the engine.

Gary

[R.B.]

Thanks for the tip.

Just a warning for all.
Be careful adjusting too high. Remember that your transmission needs to engage at the recommended idle RPMs. Too high of an RPM may do damage. Also don't forget that most of your engine time is not at idle, so "wear and tear" will be at RPM's other than idle. That being said I can't see a few RPM's either way doing any damage.