90hp oil pump

[wrxhoon]

I have a 1990 mod 90 hp yamaha and the oil injection is playing up . It seems like sometimes its getting oil up to the carbies and other times its not .
I pulled the oil pump off and unassembled it but i can see anything wrong with it, everything seems to be working as it should and no worn parts that i can see
Would anyone have any idea what could be wrong with it ?
I guess my next step would be to bench test it, has anyone done that? how did you do it ?

[boats.net]

If the pump is not pumping oil to engine then replace oil pump. Be sure to add oil to gas tank to make sure engine is getting enough oil.

[Ken]

wrxhoon,
If there is any question that the oil pump is not doing it's job, then do what boats.net guy says and replace it.
There is a procedure in the Yamaha manual to test the output of the oil pump - and I believe it's a little different for different models. You might want to get yourself a Yamaha manual - can order online at www.yamahapubs.com.
Good luck [img]smile.gif[/img] ,
Ken K

[wrxhoon]

Thanks for the replies guys, i have bench tested the pump and its working fine. I guess the next step would be to check where it mashes with the crank.
Has anyone had any problems with that?
There is no point replacing the pump if i dont find the problem .
Yes i have been running the motor with a portable tank mixed with 50-1 oil (i cant add to main tank as i'm runnuning twin 90's)