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1998 Mercury elpto 115

I

Isaachackman

New member
When I getting on plane with the engine under load I can hear a rattle nocking sound from the motor . When I was working on it I figured out that the lower unit propeller shaft had about 1/4 in in and out , is that where the noise is coming from , if so what should I do ?
 
I would start with a compression test.----Post your numbers.----Yes it could be a gear issue.----Drain gear oil and have a look.
 
I did a compression test on it it was approximately 130 on each cylinder, and I drained the oil and it was good , there was some metal fines on the drain plug . I’ll post a picture of the metal fines . I only ran it about 6 hours since the last time we changed it .
 
End play is normal for lower unit...What RPM do you operate at as lugging and over RPM( above 5500) usually will break the skirt on piston making it knock
 
i usually keep the rpm around 4500 when on plane . I was going back to the boat ramp and I was getting up on plane and I heard the rattling noise around 4,000 rpm . It only does it when I’m getting on plane and the motor is working hard , after getting on plane it runs fine and the noise goes away . Got any ideas ?
 
Also I pulled the lower unit propeller shaft out and it looked all brand new , and measured the end play and it was .050 , I take that back it wasn’t 1/4 of an exaggerating a little bit, I’m just worried it’s my motor
 
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