My M35B vibrates quite a bit up to about 1200 too, then smooth as silk. I've actually reduced the idle speed a bit, so now there's just a range I avoid. My suspicions are (A) normal for this engine, (B) aging mounts, (C) uneven load on the engine mounts, i.e., when the alignment was done there was not enough attention paid to trying to keep even weight on each mount.

Insofar as noisy, my engine is like all diesels, rattles quite a bit, but not an abnormal amount. Low fuel quality might be an issue and might be a contributor to some of your vibration too.

Lastly the smell. These engines are sealed well, but check to make sure the crankcase breather is routed either overboard, or more commonly directed to close proximity to the intake filter.

Hi Abraham,

This sounds very much like a damper plate issue to me:

[url]http://www.foleyengines.com/resources/tech-tips/zfhurth-and-borgwarner-d...

These are noisy in neutral or low rpm, and usually the noise goes away at higher rpm. I had a similar issue recently (for me, most noticeable at low rpm in gear), and replacement of the damper plate really helped a lot (my engine hours were right around where yours is).

The smell would be a totally different issue, most likely. You shouldn't have anything like a serious exhaust smell in the boat at any time under any conditions, so i'd look pretty carefully for any loose hoses/fittings in that regard (especially check that the riser is well bolted on). Carbon monoxide is a killer, so I'd put your smoke/CO detector in your aft quarterberth while the engine is running, just to be sure you're not getting a CO leak.

As Nick mentioned, I'd be suspicious of that old fuel. Diesels are compression ignition, it's a bit hit and miss at the best of times, compared to spark ignition, and having old fuel will make that much worse. Plus it will coat your fuel tank with all kinds of precipitates coming out of the diesel. If it's off to the point that you're getting pre-detonation you will get all kinds of nasty side effects with the engine, it can drive cylinder head and bore temperatures way up beyond normal and will not likely show on the heat gauge that it's happening. I'd pump it out and put in fresh and see if that helps before spending a lot of money on other stuff.

Another thing to help get rid of smells is putting ing a closed crankcase vent system. I put in a Racor and it made a big difference

I believe your only options to remove the fuel are either pump or siphon it out  you can access the tank behind the side panel in the back berth and remove the filler hose at the end of the tank. Another option would be hiring a fuel polishing firm to remove the fuel and haul it away for about $250.  Any concern about the condition/contamination of the inside of the tank?

Hi.  One thing it might be is a crack in the exhaust riser.  It's covered with fiberglass wrapping - hopefully not asbestos. (If it's asbestos, obviously replace it safely.)  When you unwrap it, if you find a fine black soot, that will be probably be coming from the exhaust leak.  Unwrapping makes the exhaust leak easier to find.

I emptied my fuel tank using an electric oil change pump. You can dump the old fuel in any old oil recycle tank as its just more refined oil. Only problem is, a full tank will probably require about 10 trips to the fuel dump site using a typical oil change pump unless you can figure out how to drain it into a bigger cpacity container.

The pump costs about $125 -$150 at WM and if you don't have one already, I think its a worthwhile investment as you can use it to change oil, suck up any bad things besides water that get into the bilge, etc.

On a different topic,anyone find the spell check on the new site???

Abraham,

I had a similar issue with vibration and fixed it by increasing my idle RPM to 1000.  Universal recommends the M-35 have an idle RPM between 800-1000.  See page 9 of the manual: http://www.westerbeke.com/OnlineManuals/200494_m320a_thru_m35b_operator_...

Ron St. Onge

C36 #1384

Even though my engine idle is low, I do acknowledge that it's not good for prolonged operation. This is true for diesel idling in generall.  Diesel engines are such that fuel flash points vs. piston position are imprecise, leading to vibration especialy in low inertia situations (idle).  Hard to say if your vibration is off-the-charts. Did the guy who adjusted your valves give an opinion in this area? Fuel issues account for the vast majority of engine woes, so if the problem is real continue along this line. Also verify if the weight on your mounts is even, i.e., one mount not excessively compressed.  This can easily happen during shaft alignment.

I'm curious about the motor mounts as well, not the upper larger adjustable mounts, but the smaller ones that go into the fiberglass (and wood?) base.  Are these thru-bolts or wood screws?  Reason I ask is that I don't see a way to fully tighten them, since I can't see how to get at the lower nut (if it even exists). 

If they are wood screws, then I think mine are starting to strip out of the wood and I'll need epoxy and re-drill new screw holes for them. 

Anyone know?

See if yours has a lock washer just beneath the upper screw head.  If the lock washers are not fully flattened, that is the telltale sign that the lower mounts are loose.

 I'm thinking this could be causing your vibration now and mine someday.

Ben,

The motor mounts are attached to the beds with lag bolts (roughly 2.5" long?)into a thin layer of fiberglass, with wood underneath.  There should be a lower nut, motor flange, lock washer, and then an upper nut.  If any are missing, you may have a problem!!

Yes, those are the ones I mean, i.e. the lag bolts Tom speaks of.  Maybe I'm just missing something simple, but I don't yet see how to get at the lower nuts.   This is an MK1.

Abraham,

Perhaps this pic will help.  These are not OEM mounts, but the concept is the same.  These are softer Vetus K75's, so yours will not have the motor mount nut. Upper and lower adjusting nuts are tightened against each other, and with the lock washer, keep the engine in place.  This engine is just about at the lower limit of adjustment in the pic. Normally the nuts and engine flange are roughly in the middle of the stud.  Left/Right adjustment is done by moving the motor mount, after loosening the lag bolts.  Up/Down adjustment is done with the adjusting nuts. Hope this helps.

What Tom shows in the picture is exactly my setup.  One of my lag bolt heads was loose, so I tried to tighten it...but tighten it against what?  There is no lower lockwasher/nut that I can see, and by definition, a lag bolt would not have a lower nut, i.e. it's just basically a wood screw, and it feels like it's starting to strip out.

I think that over time, the engine vibration wears away the wood(?) into which the lag bolt screws, and this is what I'm thinking could cause excess vibration (on MK1s at least). 

Rebedding the lag bolts seems like it would be a major job to fix.  Hopefully I'm missing something simple, coz this just seems like a poor design to me.

Abraham -
There is absolutely no need at all to haul the boat to redo the motor mounts. Replacing them was one of the first jobs I did on our boat when we bought her 4 years ago (per the surveyor's finding that they were shot); you just need to hoist up the engine a few inches to slip the new ones in. As I recall, the prop shaft and the exhaust riser needed to be disconnected (and the wood bulkhead removed), but nothing else. I raised the engine with a come-along and a bit of chain attached to a piece of 4x4 wood resting over the hatchway. Not a pleasant job, and some (interesting) contortions to get at some of the bolts, but not mechanically very complex. The worst part was repeated trips to the store to get more socket wrench extensions to get at some of the harder to reach bolts on the mounts (particularly the aft starboard one).
I replaced with the Vetus K75, as suggested by Soko. You should keep track of the existing height measurements, I used these as a starting point with the replacements before realigning the engine and found they were not far off.
Good luck!

Happy to hear that you finally had your problem fixed.  It is very helpful to have fellow owners sharing their experience.  I am a new owner too and found this forum very helpful.
Just want to share that my idle is only 600 and it rattles but once I push the throttle up to 800 it became very smooth.  However, my max rpm  only goes up to 2400.  A bit of white / grey smoke start to come out from exhaust at 2200. So I always try to keep it under 2200 yet still gives me cruising speed about 6 knots into current (1-2 knots).  Is it normal to have some smoke?  If I kept the engine running at higher then 2200 rpm for over 2 hours, I always have to scrub off the black stain on the transom after returning to slip which is annoying.
After ,  reading thru the post regarding the engine mount,  I want to attach this picture to ask if I need to tighten the nut on the top mount.  It is not tightened all the way to the mount! 
Also,  Is it easy to adjust my idle from 600 to 800 so there is no rattling on start? 
Please advise.
Thanks
 

For what it's worth I added a "Blue Hump" Hose to my boat and I think there is less vibration. I added it because it's a good idea.

Hi Abrahan
Can you explain how to adjust the idle on the engine?
I will take your advise and tighten all the nuts on the engine mount.
Thanks
Jason
 

Andres
I haven't taken a pic of this hose. I can, if needed.
This hose is a "Blue silcone hose" Available from Catalina direct. This hose is connected to the exhaust riser to aqua lift. The OEM hose is very hard and stiff. The reason I swapped out the hose was to reduce vibration to the aqua lift. If you do a search for the blue hump hose you'll find many write ups.

Jason - sent you a PM, regarding adjusting idle...