Engine vibration at idle

[JIM BRENER 1987 #504 "WI]

On April 28th I posted a question regarding excessive engine vibration and rough noise below 1000 rpm.  I logged 66 views and no replies.  This means either the question was too dumb to rate an answer, no one knows the answer or I should go back to the FAQ and search again.

While at the boat this weekend, I played with a set screw adjusting the throttle. I can keep the throttle from going below 900 RPM after which the engine runs rough but I don't know if I am solving the problem or avoiding it.  At what RPM should the engine run to move the boat at idle, in gear, slowly?

I miss the emails, I think there were more questions with more opinions answered more quickly than this forum.

Jim Brener
Wind Spirit #50 :confuse

[Roc]

Jim,
My Universal M35B idle is set at 800.  I think the spec from the manual is anywhere between 800 and 1000rpm.  Obviously, the more rpm, the faster you will go in idle, which could be tricky when you are approaching a dock.  800 seems to give the right speed and manuverability.  My engine doesn't run rough (i.e. vibration) in idle, but there is a distinct 'clackity-clack, clackity-clack' when at idle and in gear.  Put it in neutral and the clacks go away.  It was like that from the begining and the dealer said it was 'normal'.  But I'm not sure about that.  Does your engine do this??  I wonder if others hear the same noise.  To answer your question, no I feel no vibration, just the clacking noise when in gear at idle.

Roc-

[c34member]

I also idle at about 800 rpm.  The engine (Universal M35-B) is smooth and relatively quiet.  The blower motor easily drowns it out.  If you're running rough in idle and neutral, it's a problem with the fuel, air or timing.  90% chance it's fuel related.  Water in the tank, air getting into the fuel line or clogged filters are the big three fuel delivery problems.  Check the bowl of the fuel/water seperator (primary fuel filter).  I back out of my slip on low wind days without adding any throttle; just bottom low idle.  It will run in gear and at low idle as long as there is fuel to burn.

[mitch brown]

Jim-
   
  Sorry for the delayed response, but I have hull #282, and I also have noticed the engine running a lot noisier than it did years ago. I think it is from the engine mounts being worn down, if not out. I haven't gotten around to replacing them yet, as others on the list have. The excessive vibration seems to resonate througout the boat, making it much louder.  When I increase the RPM's it seems to run "quieter". IMHO it isn't anything in the fuel or the engine not running properly, but just in need of new mounts. Just my two cents worth. Good luch with the troubleshooting

Mitch Brown
Sea Vu Play #282
Long Bch CA