Need some advise

willy · #1 08-19-2008, 08:44 AM

need some ideas from you guys before I head back down to my V.
Took my son down yesterday to install rod holders on boat, went well and we decided to go out and do a little fishing late in the day.
Motor is running like a champ, full rpm and speed but a noise is occurring at higher rpm that sounds like a metalic vibration, medium high pitch and would come in only under load when you were first accelarating then quiet down and sometimes disapear.
Stopped motor on the watetr and pulled the cover, sounded like something was loose like a ball bearing in a paint can mixer machine but could not see anything wrong or loose. No alarms, no overheating, oil in reservoir.
Ran boat for another two hours and ran beautiful but noise would appear at certain rpms and repeat the cycle. Lifted the lower unit out of the water all looked tight there with prop but the noise seemed higher like around the base of engine block area but could not pinpoint at all.
Back at the dock had engine running with cover off and revving up high but could not get it to do it, only way was at speed on the water.
At higher rpm at high rpm at dock sounds like a two stroke swiss watch.

Oh and its a 1992 150 yammie.
Any ideas of what to look for let me know please cause I am stumped and now a little worried.
Only thing done diffrent on engine was I used Pennzoils new two stroke oil in the tank when I filled it up last time, I was going to use the yammie lube but it looked like he had been running Penn in it as it was not blue like yammie but black.

tsubaki · #2 08-19-2008, 09:18 AM

Normally the cowl is the culprit in most of the noises.
Ain't but a couple of other things that wouldn't show up easily.
Check the starter bolts, air damper and carb bolts or nuts.
Also look toward the bottom of the motor around the powerhead and even with a magnet for the spots you can't see for a hidden dropped bolt or nut.

willy · #3 08-19-2008, 10:30 AM

Thanks Tsubaki, going to do just that, the noise sounds external to the engine but visual showing nothing yesterday???

parishht · #4 08-19-2008, 10:38 AM

May be a bearing going bad in your lower unit.

I remember on my older cars that when the water pumps went,
they would make a noise and nothing looked wrong on the outside.

willy · #5 08-19-2008, 10:42 AM

how would I check for that Parish? any idea?
It does sound higher but I know vibration can carry a lot

C YENSEN · #6 08-19-2008, 10:46 AM

sounds like the solution to the problem is hanging on the back of Lumber's boat not to far from you......i will even come up and help you "borrow" it

parishht · #7 08-19-2008, 10:48 AM

An engine stethescope could help you pinpoint the noise.
The other way is to tear down the unit and check each bearing.

But ifI understand your post,
the noise is only when in gear, under power with a load (pushing water).
That would indicate something in the drive.

macojoe · #8 08-19-2008, 11:04 AM

When I got my 94 150 Yamaha it had a noise like that and was junk right after?
But that said that motor had ben over heated before I got it and who knows how or for how long?

Good Luck

C YENSEN · #9 08-19-2008, 11:05 AM

I agree with Parrisht. take and old dow rod or piece of long skinny wood (broom handle) and hold it to your ear, and possible noise areas. should tell you where the noise is coming from.

willy · #10 08-19-2008, 11:29 AM

that sure would be tricky at 28-35 mph on the water cause it makes no noise at all sitting at the dock at full rpm
better get my life ins up to date, I can see it now, man dies on water with broom stick in his head!!