2002 yamaha 115 four stroke not running 100%

stracuzza

Cadet
Joined
Feb 1, 2009
Messages
12
so i bought the motor and finally took it out, when i backed it off the trailer it wants to cut off for a split second than it gets to going, i put it in forward and the same thing where it might shut off when i first start to throttle up , went to ease it up on plane and it started having a slight shake and didnt seem like i was getting the power it should be at WOT it felt like i was only going 3500 rpms(dont have a rpm gauge hooked up yet) sounded like it was busting up a bit as almost a misfire... rode for id say 5 minutes and motor seemed to slow down by itself not alot but noticeable.... came off plane and and just rode with motor in forward back towards the dock when i would get in the gas a little it had what seemed to be a miss ... tried to get up on plane a second time just to see if maybe it might've been a first time thing but it wouldn't even get going on a plane ... so we just boozed cruised back to the dock and got it back on the trailer..... the motor sat up on the boat for a few months before we took it out today... i put a new water fuel seperator with the clear bottom and new fuel line thinking about taking it to get it checked out and the oil changed and have it inspected.... wondering what the problem may be
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,877
Re: 2002 yamaha 115 four stroke not running 100%

bad gas or fouled carbs, or both
 

sdsaw

Petty Officer 2nd Class
Joined
Aug 19, 2007
Messages
188
Re: 2002 yamaha 115 four stroke not running 100%

bad gas or fouled carbs, or both
Nope on the fouled carbs.
That's a EFI motor

Slight chance that it's the gas

More than likely the VST filter needs cleaning or dirty injector(s)
You can diagnose the clogged filter with a fuel rail pressure test at the problem RPM
Send the injectors out for a professional cleaning job along with new screens and flow testing (before and after)

Avoid running the motor until you fix the problem because a lean fuel mixture can cause engine damage
Run it just enough for the test
 
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