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Had my 200 VMAX since new in '03. For the past several months it is idling rough and sometimes cuts off when put in gear. Also runs rough when power is 1st applied. Runs perfect at speed with no loss in performance. This engine has never been touched other than anual maitenance. I just put new spark plugs in this year.
I'm thinking fuel but wanted to hear from the experts.
Have you changed fuel filters ? If so then might be fuel pump.
JOHN202
Nope, but I will now. Thanks for the quick reply.
are the new plugs gapped correctly?
Check plug gap but most likely you need to change the 3 fuel pumps on the passenger side of the engine http://www.bassboatcentral.com/smileys/USA1.gif
I've got the same symptoms. The above suggestions didn't fix anything. If the lift pumps were not sending enough gas, you wouldn't reach WOT. They could be leaking into the intake if the diaphragm is bad...you could loosen the 2 mounting bolts and see if fuel drips down. I have good pressure in the low side and high side fuel systems. All filters are new and O2 sensor is new. I've tried 2 sets of plugs. I'm completely stumped and caving in and taking it to a Yamaha Master Tech. I'll try and let you know what the problem was once it's fixed. I hope it isn't the Stator coil...they are $500! My plugs are usually wet with oil after I run it...so for some reason I'm not getting good combustion at low speed. If i get it above 1500 rpm, it'll run fine all the way up. Once I bring it back down to idle it'll start sneezing and sometimes die. Good luck...I need it.
Sounds like the Throttle Position Sensor (TPS) to me.
I will start with the filters and go from there. Mine does not spit, it just idles rough and cuts off occassionally when powering up.
But I would like to know what you find.
Good Luck!!
ive got the same problem on my 2.6 lter hpdi. it runs rough at idle and when taking off. once above 1500 or so rpms, it runs perfect. mine seems to be running rich. i had the low pressure fuel pumps changed, the o2 sensor cleaned, new plugs, and new fuel filters installed. mine seems run run worse when it is hot outside. i am at a loss. if you find the problem please post.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by craigs06 »</TD></TR><TR><TD CLASS="quote">Sounds like the Throttle Position Sensor (TPS) to me. </TD></TR></TABLE>
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Thanks Rich, my battery is in it's 7th year and is over due to be changed. I have tested it with an automotive tester and it checks ok. I will change it anyway due to age.
Thanks for your post.
Some info re battery and understanding o2 sensor readings is in my post here http://www.bbcboards.net...18096
What idle speed are you running? What is your TPS reading at this? Have you done Sync and link of throttle butterflies? Have you watched your fuel rail pressure when it dies?