head cover bolts

[neverenoughx2]

I bought a rebuilt power head several years ago. I was losing rpms so i pulled the head covers off and noticed one was leaking and gaskets had to be replaced. The problem is I thought I bought a rebuilt 250hp yam but now i see it is 225 hp the parts start with 62j. I am annoyed at that but two bolts are shorter than the other 18 on each head cover. Now I have the manuel for the 1994 250 it has only 1 bolt shorter on each head. I can't find the year of this block and have no idea which holes the shorter bolts go into. There are definitely 2 on each side. Can anyone help. I don't wanna put this back together wrong.

Thanks

[boscoe99]

What is the complete model identity of the motor? Or, what do you think that it is?

It is not uncommon for two different HP motors to share the same part numbers. Both the 225TXRT and the 250TXRT use the same part number head and head cover.

The parts catalog can also be used to indicate what bolt(s) goes(go) into what hole(s). Looks like three different part number bolts are used for the head and head cover.

1995 250TXRT Yamaha Outboard CYLINDER CRANKCASE 2 Diagram and Parts

[zenoahphobic]

Faily determining where bolts go, a piece of wire inserted into hole could determine which should be the shorter bolts.
I would also be curious as to what actual powerhead you got.
I don't know, but bore diameter and stroke not different so if someone can tell whether porting different and how to tell. Maybe differences outside of powerhead??

[99yam40]

I am fairly sure it is probably just something as simple a mapping of ecu or shape of combustion chamber.
Not much difference in 25 HP when you get up that high