Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: "Rattling" sound when '95 Johnson 90 RPMs are lowered

Posted by Hines Pointer on 10/05/05 - 5:09 PM
#1

A couple of years ago I bought a 1995 Montauk with a 1995 Johnson V4 90 hp engine. I mentioned in an earlier thread that the "no oil" alarm has gone off recently on two occassions while idling, but upon checking there's plenty of oil in the tank and -- when restarted -- the engine is fine. BUT the other thing I forgot to mention is that recently, when I pull back the throttle in the 3-4K rpm range and the 2-3K rpm range, there's a pronounced rattling sound. A friend said that's normal with mercury outboards, but not a good sign with OMCs. Again, am I facing a situation of something failing, or should I not be concerned?

Thanks in advance for your advice.

Posted by Hines Pointer on 10/31/05 - 5:53 PM
#2

Sorry I stumped you guys, or perhaps the problem is unique to my motor.

Posted by Joe Kriz on 10/31/05 - 7:45 PM
#3

Hines,

I have an excuse. I was on vacation when you posted this...
However, I still can't come up with an answer. I am stumped...
Is the rattle coming from the engine or the boat?
If it is the engine, I would have a mechanic take a look at it and maybe go for a test ride with you.

Posted by Hines Pointer on 11/01/05 - 7:37 AM
#4

Joe:

Thanks for the advice. The noise seems to come from the engine block, although I can't pinpoint it. A commercial fisherman friend on Martha's Vineyard told me that this type of noise is common and not problematic with vintage Mercury engines, but can signal problems with vintage OMC engines. I'm winterizing my boat shortly, so I'll have the mechanic check it out.

Thanks again.

Michael

Posted by Jeff on 11/01/05 - 2:11 PM
#5

Hines,

My Evinrude 235 had a rattle at about same RPM range (3500 - 4000). This did concern me for a while because I could not figure out where it was coming from. However, once I was able to get a person I trusted to pilot the boat I spent some time looking over the motor while it was running. Come to find out it was the front of the motor cover latch that was rattling. Might want to do the same on your boat to easy your nerves.

Posted by Doug V on 11/08/05 - 8:33 AM
#6

My brother in law had an Evinrude 40 that always ran great, but we did not like the rattle it had. It always made you wonder if things were getting loose inside.

He sold the boat, I bought the engine and installed it on one of my old boats. While doing this, I had the hood off running it in the test tank. I noticed that there was no rattle. I installed the hood, and there was that rattle! It turned out that the latch strike rivets were loose. I replaced the rivets with stainless machine bolts and I never heard that rattle again.

Doug

Posted by Hines Pointer on 11/08/05 - 6:51 PM
#7

Thanks for the thoughts regarding the cover latches. I checked them today, however, and both front and rear are snug and without rattles.

Posted by Indy on 03/28/06 - 5:45 PM
#8

Never ignore the no oiling light...I would suggest you have your service tech do an oil consumption test on it. Also check compression. You should consider double mixing the oil untill you get this done to avoid powerhead failure. The VRO pump may going out. Good luck.;)

Posted by MW on 03/28/06 - 6:50 PM
#9

A friend with VRO said that at different rpm's, VRO pump output can vary. I had the VRO factory disconnected when I bought my motor last year. At least with old school style, you know it's (oil) in there and working, less to go wrong out there (Hopefully). Always mix some oil with your gas EVEN WITH VRO !

mw