YAMA VMAX LEAKING FUEL AT PROP

[MIKEJOHNS]

I HAVE AN 01 YAMAHA VMAX250 OX66 . OCASSIONALLY , MOTOR HAS BEEN CUTTING OUT AT HIGH SPEEDS . TODAY , MOTOR CUT OUT , RAN BAD ALTOGETHER . GOT HOME AND TRIED TO CRANK IT , AND IT WOULDN'T CRANK . WHEN TURNING THE MOTOR OVER , GAS LEAKS FROM BEHIND PROP . ANYBODY MIGHT CAN HELP ME WITH SOME IDEAS ?

 

[rodbolt]

Re: YAMA VMAX LEAKING FUEL AT PROP

if its a US market motor can ya post a model number?

 

[MIKEJOHNS]

Re: YAMA VMAX LEAKING FUEL AT PROP

if its a US market motor can ya post a model number?

 

[MIKEJOHNS]

Re: YAMA VMAX LEAKING FUEL AT PROP

NOT SURE IF IT'S A US MARKET MOTOR , BUT THE MODEL NUMBER IS VX250TLRA . I PULLED THE PLUGS AND LOOKED AT THE PISTONS . THERE WAS NO VISIBLE DAMAGE . WISH I WOULD HAVE CHECKED THIS FORUM WHEN MY PROBLEMS FIRST STARTED !

 

[rodbolt]

Re: YAMA VMAX LEAKING FUEL AT PROP

no worries, remove the fuel pumps from the block and see if the block side of the diaphrams are wet.
you most likly have one or more bad pumps, its possible the needle valve in the vapor seperator is leaking, they dont leak often but if they do it dumps fuel into the intake.
the 3.1L motors do eat lift pumps though/.
bad lift pumps are very common and one of the few things that can kill a yamaha.
when one of the pumps fail it dumps gas into the crankcase.

 

[MIKEJOHNS]

Re: YAMA VMAX LEAKING FUEL AT PROP

YOU WERE 110% CORRECT ON YOUR DIAGNOSIS . 2 OF MY PUMPS HAD RUPTURED DIAPHRAMS . PUT ON 3 NEW ONES - RUNS LIKE NEW . THANKS FOR YOUR HELP . NOW I CAN GET BACK TO BLOWING BASS BOATS WITH 200/250 MERCS OUT OF THE WATER !
THANKS AGAIN .