My motor is an 03 with 150 hours on it. recently I have lost top end. I can't get higher than 5300 rpms, when I could get to 5800 to 6000. Also when under WOT the trim unit will not go higher than 25%. When I am at idle no issue.
Originally we thought that one of the fuel pumps had a bubble in it so we replaced it. There are no codes. I have replaced all plugs, fuels filters etc, but can not figure out what is going on.
Any body have any suggestions
Modified by Willard1602 at 4:22 PM 4/11/2011
Check the O2 sensor. Lose of WOT is common with a fouled or non-functional sensor.
mechanic said he checked, he also changed the filters, it makes no sense. The motor only has 150 hrs.
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Amistad Tackle »</td></tr><tr><td class="quote">Check the O2 sensor. Lose of WOT is common with a fouled or non-functional sensor.</td></tr></table>replace it.
"Don't be afraid to see what you see."
Ronald Reagan
Maybe your engine rpm issue is due to not being trimmed up properly due to the 25% trim problem???
Get the trim fixed. Other than that change the O2 sensor as others have indicated. Do a compression check and take it from there.
Loss of top end is classic signs of a fouled O2 sensor. However, if you can't get the trim up where it should be, that would also result in a drop in RPM's. Checking and cleaning the O2 sensor is free. I'd atleast check it, but fix the trim problem.
2002 Pathfinder 2400V
2002 Yamaha 225 OX66
Agreed but the 02 checks out no codes
fouled o2 sensor will not throw a code? how is he checking it? only correct way is to pull a voltage output reading on it running
he checked the codes in the memory
Codes in the memory? Not sure thats possible on a non HPDI motor.
Marks Props 317-398-9294, 1850 East 225 South, Shelbyville, Indiana 46176 propellerman59@gmail.com http://www.marksprops.com/index.html
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Willard1602 »</td></tr><tr><td class="quote">he checked the codes in the memory</td></tr></table>
You need a better mechanic. Get the trim fixed, then recheck it for WOT rpms.
that motor doesnt store any codes i dont think.
"Don't be afraid to see what you see."
Ronald Reagan
It will store one code. If there is more than one code the winky blinky will flash the lowest code first. When that code is fixed then the next one will flash.The codes go from a 13 to a 44. There is no code for the O2 sensor. It needs to be checked with DVOM. See sticky posts about O2 sensors at the top of the page
Could it be a bad tach? Are you losing speed?
2005 G3 HP200 DC with 200hp V-MAX OX66
68.8 gps at 5600 rpm best speed yet
Was told by multiple Yamaha mechanics, there is no readouts on an ox66 Yamaha.
Order you a NTK 21006 O2 sensor (around $40 from Advance) and a gasket kit. Cut the plug off your old and slice it to the new one. I've been running this one for about a year now with zero issues. Also, check your fuel lines for kinks.
1999 Champion 203
2000 Yamaha OX66 225
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