1984 Evinrude outboard knock 115 HP

S

sum fun

Recruit
Joined
Feb 27, 2004
Messages
3
We are breaking in a 1984 Evinrude been doing the double oil in the gas have about 15 hours on it now and droped to the 50 to 1 mix motor runs great but when we are droping from 5500 rpm to say 3500 rpm slowing down we have noticed a slight knocking noise when we idle we dont notice it at all. could this be exhaust ports just below the cover out boards are noisy anyhow just not sure if this is normal dose not sound like a rod knock I added more oil just to be sure no change <br />at all I am going to change the lower unit oil this week is synthetic oil a good Idea? Checked out the prop all looks good there Thanks any help would be great
 
C

Cricket Too

Lieutenant Commander
Joined
May 14, 2003
Messages
1,732
Re: 1984 Evinrude outboard knock 115 HP

sum fun......Is this a ping or a loud knock? If you decelerate too quickly, a motor will ping, most likely your pinging is normal, you should always try to decelerate slowly to avoid this though. Synthetic oil in lower unit is a good idea, there is nothing wrong with conventional, but synthetic resists water better and tends not to foam up as much and I believe it usually has a higher sheer strenght. Good luck.
 
M

Mettaree

Petty Officer 1st Class
Joined
May 17, 2003
Messages
292
Re: 1984 Evinrude outboard knock 115 HP

Do a compression check - just to be on safe side.<br /><br /> :)
 
S

sum fun

Recruit
Joined
Feb 27, 2004
Messages
3
Re: 1984 Evinrude outboard knock 115 HP

thanks guys I will do the synthetic oil and do the compression check should be around 120 to 130 <br />is that correct
 
LubeDude

LubeDude

Admiral
Joined
Oct 8, 2003
Messages
6,945
Re: 1984 Evinrude outboard knock 115 HP

mmcpeck I think has nailed it, Try the slowing down slowly next time as suggested and see if it dosnt go away. Ive experienced that noise myself before and it will go away if you slow down slowly.
 
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