99 250 YAMA HIGH SPEED DROP

[marinegrh]

got a 99 250 efi yamadawg, she'll run for about 2 minutes then drop r's, shut down and restart run fine for a few and then drop r's again, fuel pumps ok, fuel pressure ok, injectors good, seems fuel related, have no codes, even ran on a sepatate fuel supply withno change, doesnt this sound to much like the o2 sensor, any help or comments appreciated<br /><br />fair winds and following seas my friends

 

[rodbolt]

Re: 99 250 YAMA HIGH SPEED DROP

hello<br /> O2 sensor will usually cause a drop to about 3800-4000. have you done the regular maintenance on this motor or just ran it cause it always ran ok? have you serviced the VST filer? and have you rebuilt/replaced the fuel pumps? I always do the pumps every 2 to 3 years on all my customers boats. do it long before it is needed.is the overheat alarms working ?<br /> do a compression test before anything else to insure mechanical damage has not already occured. good luck and post more information