(not) good vibrations

anaisdog · July 13, 2015, 01:39:24 PM

i have a c34, 1986, hull 99. i had a new shaft put on a few years ago, and the prop straightened. i ran her aground, into soft sand, over a year ago, and she's been fine since then. i took her out once, for about 15 minutes of motor and 4 hours of sail, a few weeks ago and then I took her out for a very long (1.5 hour) motor yesterday. this is the only time i've taken her out, this year. the engine was extremely loud and vibrated a ton. the rpm's did not seem out of wack. i'm exhausted from the motor yesterday, espcially in my arms. the coolent reseviour, which was put on a few years ago, shook enough to spew coolent all over underneath the sink, in the head. Outside of diving down and looking at the prop, to see if anything is on it, what else can I do before I have to spend real boat bucks, getting her hauled out and looked at?

thanks

becki kain
detroit

KWKloeber · July 13, 2015, 01:43:48 PM

becki I think you have an M-25?

wither her running, try cracking and backing off the injector line one at a time so that that cylinders injector isn't getting fuel -- to see of the RPM chamges. You might have her running on one or two cylinders?

KK

anaisdog · July 13, 2015, 01:45:11 PM

thanks Ken, how do you do that? yes, she's an M25 kabota tractor engine. i should have said that.

Mike and Joanne Stimmler · July 13, 2015, 01:51:40 PM

Beki, also check the motor mounts to see if any are separated or broken,

Mike

KWKloeber · July 13, 2015, 02:04:42 PM

Quote from: anaisdog on July 13, 2015, 01:45:11 PM
thanks Ken, how do you do that? yes, she's an M25 kabota tractor engine. i should have said that.

Loosen the compression nut on the tubing that feeds each injectors, one at a time. Yoru engine parts manual will show the fuel lines going to the injectors. Best to use a "tubing wrench" or "flare nut wrench" for that ($12 set at Harbor Freight) -- less likely to round off the nut (they need to be very tight) than using an open-end or adjustable wrench on the nuts. Note that it will be a Metric size, not Imperial size wrench. The theory being that if you have a cylinder not "firing", when you interrupt the fuel flow, you won't notice a difference. You WILL notice a difference if you interrupt the fuel flow to a good cylinder. Put plenty of paper towels around the nut to catch the diesel spray.

KK

Ron Hill · July 13, 2015, 02:09:43 PM

becki : You didn't say, but is this happening all the time the engine is running?
Both in gear? and out of gear??

anaisdog · July 13, 2015, 02:14:06 PM

both. it was REALLY loud and really vibration-y. i'll try to find the motor mounds then, thanks

KWKloeber · July 13, 2015, 02:16:50 PM

Quote from: anaisdog on July 13, 2015, 02:14:06 PM
both. it was REALLY loud and really vibration-y. i'll try to find the motor mounds then, thanks

parts manual - probably called "isolation" mounts or engine isolaters.

anaisdog · July 13, 2015, 02:23:45 PM

k. i'll find the m25 manual and look for them if the manual is not onboard. thanks!

KWKloeber · July 13, 2015, 02:27:33 PM

Quote from: anaisdog on July 13, 2015, 02:23:45 PM
k. i'll find the m25 manual and look for them if the manual is not onboard. thanks!

yep - M25/M25XP/M25XPA parts manual, not owner's manual. It's on the C34 site and C30 site.

k

anaisdog · July 13, 2015, 02:31:39 PM

it is? oh, duh!

Ron Hill · July 13, 2015, 02:32:28 PM

becki: Pull the steps out and look at the engine. In the front you'll spot (on each side) where the engine sits on the rails (one on each side) attached to the floor under the engine. 2 engine mounts in front (one on each side) and 2 in the rear (one on each side)

I'm sure that you have a bad mount(or two or three) and/or a locking nut/s on two (or more) have backed off (or missing!!) and the lower adjusting nut/s are all out of whack!

Think you need to get someone that knows about engines to look at it for you!!!!!! duh!!!

My thoughts

anaisdog · July 13, 2015, 02:48:40 PM

the problem is, the man mechanic in the area and i have had a little of a falling out.

anaisdog · July 13, 2015, 02:49:53 PM

also, Ron, that would make sense since my crew reminded me that when he stood on the stairs, the vibration seemed to be a lot less. i'll look wednesday. work is in the way of getting to my boat!

Stu Jackson · July 13, 2015, 05:26:15 PM

Quote from: anaisdog on July 13, 2015, 02:49:53 PM
also, Ron, that would make sense since my crew reminded me that when he stood on the stairs, the vibration seemed to be a lot less. i'll look wednesday. work is in the way of getting to my boat!

Becki,

One of the old, old, old tips & tricks was to put four stick-on felt coasters, like for a glass. living room coffee table under the bottom of the top step section.

Probably comes from the old FAQs in the C34 Tech wiki.

Given your situation, I suggest looking again at the Critical Upgrades, "Look at your engine while it's running." Take BOTH covers off and watch what happens.

I'm still runnin' on 30 year old mounts. I'm certifiably crazy. But, I do like to know what's happening down below and I can feel it through my feet standing behind the wheel.

We have a newer 100A alternator with a Balmar external regulator with a Small Engine Mode toggle switch. Check your electrical system and let us know what you have. Like, OEM alternator, etc.