Oil Pump question

bumblebeetn

Cadet
Joined
Jan 7, 2005
Messages
17
I got my new powerhead mounted. The motor is a 1989 90 hp yam. Everything bolted up fine except the oil pump.When i ordered the powerhead the rep asked me if it has 2 or 3 bolts for the oil pump. I told him 2 . It actually had 2 bolts holding the oil pump on but after taking the pump off the old block it actually has 3 holes but the 3rd hole didnt line up with the pump so i didnt think anything of it. When i got the new powerhead and got it mounted,the bolt patterns for the oil pump dont line up. The new powerhead has 2 bolts for the oil pump on the right side. 1 around 1 oclock and the other around 5 oclock. So ive ordered a new oil pump. (marine dealers around here in nashville dont stock these pumps because they say they hardly fail)Question,the tech told me when i get this new pump i may have to grind the block some to get the pump to fit. Has anyone experienced this before,and how much grinding actually wll i have to do? Thanks <br /> P.S. I was going to disable the oil pump and run premix but the marine dealer talked me out of it saying that hes never seen a yamaha oil pump fail unless due to neglect. I was happy with the pump on the old powerhead but kinda leary about grinding on the block
 

Ray Neudecker

Lieutenant Commander
Joined
May 25, 2004
Messages
1,656
Re: Oil Pump question

You are only grinding on a flange on the block. Depends on what you have to grind with how difficult it is.
 

bumblebeetn

Cadet
Joined
Jan 7, 2005
Messages
17
Re: Oil Pump question

Thanks Ray,The guy at the marine dealer said its not much to grind ,just wondering if this has been done. From what hes telling me they made a few changes on block around this time.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Oil Pump question

he is correct on the pump. I have not ground one in years but its a minor fit issue. I seem to remember a tech bulliten about it some place. its a minor clearence issue.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Oil Pump question

no real timing issue. just make sure the drive tang on the pump fits the slot on the drive shaft.
 
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