Engine Mount question

[Sefuller]

I replaced the engine mounts on our Universal M25 in an Oday 34 several years ago, using the Bushings Inc. DF 2205-2 mounts which were similar in style to the originals. My hope was to eliminate the vibration that is annoyingly pervasive through the entire boat when motoring. At the time I replaced the cutlass bearing, dripless packing gland, had a new prop shaft made and had the flange fitted to the shaft, and mating faces machined. The original installation was pretty well aligned, and I was careful in getting the new shaft aligned as well, so I am reasonably confident the issue is not alignment related. The new mounts made virtually no difference in the vibration however. I am getting ready to revisit this issue and in reading through some past threads, I noticed Maine Sail referenced a Westerbeke enclosed motor mount for the M25XPB (Westerbeke part #40510), and I am wondering if I could use this mount on my M25? I can't find any specifications online as to the mounting hole locations. Most websites list the BI style mount for the M25, but I am not confident buying the same style from a Universal/Westerbeke dealer is going to get me any different performance than I am getting from the BI mounts.

 

[woodster]

have you adjusted your valves lately if not do that and see if that smoothes up you engine some ...just a thought

 

[Sefuller]

have you adjusted your valves lately if not do that and see if that smoothes up you engine some ...just a thought

Already done I've never been on another Oday 34 or 35, but compared to most other boats I have been on, ours definitely has more engine induced noise and vibration. It will rattle the teakettle off the stove! Last year I rebuilt the exhaust riser and used a silicone hose from the riser to the muffler as well, thinking that may reduce some transmitted vibration, but so far nothing has made any difference.

 

[Mark Maulden]

Many moons ago, i had a Gulfstar 44 with a 4-154..it shook the whole boat at lower speeds. Rigging would rattle...Replaced the mounts with Ford Lehman mounts. Was very satisfied.

 

[kloudie1]

Look for something that moves, hitting a hard part of the hull.. heat exchanger, transmission sump, that big exhaust hose that goes up under the port side combing.. prop shaft hitting inside the stern tube, etc ..sometimes you can find those by shaking the engine by hand when it is cool. grab alternator or valve cover and rock the engine as violently as you can, side to side and listen for the bump.

 

[Ken Cross]

Do you have a 2 blade prop? Depending on the underwater configuration of your boat I understand going to a 3 blade can make a huge difference.

Ken

 

[Skipper]

Also please specify if the vibration is present in neutral, while varying the rpm with the throttle.

 

[Sefuller]

Two blade prop, vibration all the time, even at idle in neutral, and nothing hitting where it shouldn't - I've had several years to check

 

[Skipper]

Two blade prop, vibration all the time, even at idle in neutral, and nothing hitting where it shouldn't - I've had several years to check

Ok so it's -probably- not the driveline.
A 3 cyl has a bit of vibe to it, but if it is excessive as you describe, and present in neutral at similar rpm, then I'd start looking at rough engine troubleshooting.
Valves, seats, injectors, compression, exhaust(riser). Also could be an unbalanced flywheel/crank/other engine part, but that's more difficult to discover, and drastically less likely.
Any smoke while running after initial startup?

 

[rardiH36]

Adding to the posts suggesting to look at the engine: Several years ago, my engine stalled and required bleeding of the fuel system due to sucking some air into the line when I let the fuel tank level get too low -- and then encountered a lot of swells.

Afterward, the incident prompted me to do some long deferred maintenance to my 1980 2-cylinder Yanmar. I replaced my fuel line and renewed all of the fittings between the tank, Racor filter, the engine filter, the low and high pressure pumps, and the injectors.

The next time out, I noticed that my 2-cylinder Yanmar engine didn't seem to be vibrating as much as before and it just sounded smoother.

Sometime later, I happened upon a forum post or article (I now can't remember which) that informed that a small air leak into even just one of the cylinders would cause it to fire inconsistently. In which case, the resulting imbalance between the cylinders would be a source of engine vibration.

Just another item for consideration.

 

[Chris Patterson]

I would rebuild the injectors.

 

[Sefuller]

Valves, seats, injectors, compression, exhaust(riser). Also could be an unbalanced flywheel/crank/other engine part, but that's more difficult to discover, and drastically less likely.
Any smoke while running after initial startup?

No smoke other than trace amounts near full throttle - mostly noticeable at night by the stern light and the normal 2 - 3 seconds right after start up. I adjusted the valves last year - they weren't too bad and only made a very slight if any improvement. I have not tested compression, but based on the fact it starts well even in cold temps, I've never suspected it to be a problem. Exhaust riser was replaced last year. I suppose I could have the injectors rebuilt, but again nothing else leads me to conclude that is necessary. Based on reading lots of posts about engine mounts, it seemed like that was a likely place to start but I still haven't gotten an answer to my original question about whether Westerbeke part #40510 would be suitable for an M25 engine??

 

[woodster]

I still haven't gotten an answer to my original question about whether Westerbeke part #40510 would be suitable for an M25 engine?

are they rated the same ...you may have to bite the bullet and get a set and see if that works for you ...but i would go back to the original ones ....there are a lot of boats with good results from the original set.....if you know all the things that have been suggested are in good repair ......then by all means experiment with other brands....

 

[Ken Cross]

One thought I have: I don't know your experience level, but I don't have as much as many here on this site. Is the amount of vibration within the normal levels we all have running small diesel engines? Without measurements (which would require accelerometers) I'd find myself guessing if mine is worse than normal. I used to think my Honda 9.9 was noisy before I owned a diesel.
Ken