Yamaha 225 OX66 RATTLE AT IDLE

Joined
Oct 14, 2005
Messages
21
I have a 2001 Yamaha 225 OX66. In gear at 500 RPMs it has an intermitent rattle. it will make a rattle noise for about 2 secs and then quite for about 2 secs. It has what I consider a rough Idle, but I understand these motor idle a little rough. once I throttle up to 600-700 it runs fine, no rattle. I have had the boat about 6 months, it has always rattled that I remember. I have checked for loose parts, the prop and couling ect and they seams fine.<br />ANYONE HAVE ANY THOUGHTS OR EXPERIENCE THE SAME ISSUE?<br /><br />Maintenance I did last month to get ready for summer, new plugs, O2 sensor, High pressure fuel filter, fuel filter, lower pressure pumps, water pump, poppet valve, thermostats, water separater, run yamalube oil and ring free.
 

rodbolt

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Sep 1, 2003
Messages
20,066
Re: Yamaha 225 OX66 RATTLE AT IDLE

you can try stepping the idle up to 625 RPM in gear , but the gear case tends to rattle on some of those engines, sometimes its due to incorrect water pump assy other times its an engine miss.<br /> but the idle speed is 625 in gear in the water unrestrained.<br />at 500 its gonna constantly try to run on all 6 cylinders and it does not do it well.<br />post a model number and we can identify which ign system you have.
 

John from Madison CT

Petty Officer 2nd Class
Joined
Oct 14, 2001
Messages
176
Re: Yamaha 225 OX66 RATTLE AT IDLE

Rodbolt: Didn't some of the earlier Ox66 models not come with the water pump shaft "shims"? My '97 was this way and I had a low speed (low RPM) rattle.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Yamaha 225 OX66 RATTLE AT IDLE

from 95 the V models had a spring washer and a set of spacers just above the impeller held in place with a lock ring and collar. the proper way to reassemble is to pull up on the shaft while seating the collar. this allows the water pump to keep the drive shaft from slapping up and down.to many folks install it without pulling the shaft up and its usless and will rattle.<br /> if your not gonna install the collar correctly why bother at all is what I tell them.
 
Joined
Oct 14, 2005
Messages
21
Re: Yamaha 225 OX66 RATTLE AT IDLE

Rodbolt,<br />My Model number is SX225TXRY<br />YEAR 2001, HP 225 OX66 Fuel Injection.<br />I did change the entire water pump assy, and seals below it. Followed the service manual.<br />The motor idles in gear at 500 and will sometimes dip to 400 on the digital gauge. I just looked in the service manual and it tells me 730 RPM,I assume thats in neutral with the boat in the water. I will go ahead and set it at 625 in gear unrestricted and see how it does. Thanks as always to everyone for the Help.
 
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