92 Johnson 150 Faststrike rattling noise

[mitchell301]

my 150 Johnson has a rattling niose coming from it. I hear it more at mid throttle range. Kind of sound like when you shake a can of spray paint and the ball rattles around, just not that loud.
Engines runs strong and haven't noticed any loss of performance.

Any ideas what it could be and how to do any checks?

Thanks.

[Stratos190fs]

That is probably piston slap... is it more noticable on decel?

[RUSTY63]

Have you checked for loose parts like steering components. motor cover latch handles?

[Lockjaw]

My money is on the lower unit. See if you hear it with the engine in neutral versus going across the lake.

Better yet, pull a drain plug.

[THE WITCHDOCTOR]

Last one I heard doing that had water in #1 BUT look for all the little things first!

[mitchell301]

Stratos....it seems to be worse at steady speed. Piston slap was my first guess. Wht would that mean as far as fix and a cost?

Rusty...i have checked for loose stuff, but need to do a though check.

I guess I need to take off cover and have my son drive down lake while i listen next to motor.

I have pulled LU drain and thre was a little water, but noise seems to come from higher up.

Water in #1????? That be a head gasket???? Could I tell that from spark plug condition?

Thanks guys for feedback..

[RUSTY63]

Fix the water in the lower unit first and have the dealer check for gear damage.

[jglenn]

water in any cylinder is easy to spot form the plugs. The offending cylinder's plug will look like it was sand blasted CLEAN

[Lockjaw]

All of the lowers I have had fail sounded like the engine was knocking, however the knocking doesn't match the engine speed it that makes sense.

On the 200 that just went away on my old boat, I was turning it close to 6000 rpms, and a rod knock at those RPMS would be obnoxious, but because of the reduction through the lower unit, it wasn't as bad.

It was the same on the 70 HP engine I had, and I trashed it so bad it locked the motor up solid, and I actually though then engine was locked up. Nope, just the lower.