noise in motor

[james m b]

I have a 1995 115hp. Mariner the motor runs fine then when you run it for awhile and slow back down you can hear some kind of a sound like a bearing sqilling.It only starts doing this after its been run a few miles.When I take it out the next time you won't hear this sound until you run it awhile agin ,don't know if in the foot or motor.IF ANYONE CAN HELP I WOULD APPRECIATE THANKS

 

[waterinthefuel]

Re: noise in motor

Well the only thing I can ask is does it do it when it's in neautral? If so, its not the foot. Other than that I can't imagine what it could be.

 

[james m b]

Re: noise in motor

no it does not do it in neautral if i remember right

 

[james m b]

Re: noise in motor

I will have to take it out tomorrow to make sure

 

[Texasmark]

Re: noise in motor

I think that you should investigate your lower unit oil before you go out this next time; maybe even change it if you haven't in 6 mos salt water, 1 yr fresh. Use the proper oil from Merc if you can.<br /><br />----------<br /><br />On the powerhead, insure that you are running at least 50:1 TCWII or III, and a decarb might be in order....might have a little rust on a roller bearing.<br /><br />--------<br /><br />Only thing that comes to mind is the top bearing on the drive shaft; right under the water pump (supports the top end of the shaft) that has to be lubricated from oil wicking up the shaft. If the lower unit oil is low this could be inadequate and the bearing is running dry. Course if you have water in the (lower unit) oil that's another story.<br /><br />Mark

 

[james m b]

Re: noise in motor

just changed oil in lower unit looked fine,carbs been rebuilt two weeks ago, motor been rebuilt 0.30 over only has 40 hours on it.

 

[ronnieboy]

Re: noise in motor

vacume leak? carbs tite?, check for interference with flywheel, maybe,

 

[james m b]

Re: noise in motor

do you think this could be the main seal on the crnkshaft maybe got water in it

 

[andy6374]

Re: noise in motor

I'd suspect the shift cable is a bit off. Make sure the engine isn't prematurely going into neutral when backing down. However, I think we need Laddies, Clams, or Rodbolt or someone of that level of experience to chine in here.

 

[Texasmark]

Re: noise in motor

Fresh rebuild? I'm sure you mean .030 over which is a big boring job. Maybe a roller bearing isn't getting adequate lube, or is too tight....like a dimensional stackup or something. Could be a ring is getting hot (get the right bore dia, rings, and pistons?) and the ends are butting together and the ring gap is too small so the ring just gets bigger, dragging on the cylinder wall.<br /><br />I might go with the too tight part as the engine has to heat up to get it to do it and that would mean metal parts expanding and not having adequate room to expand so they bind.<br /><br />What oil mix are you using? Lot of folks recommend 25:1 for the first 50 hrs or so.