1990 90hp Lower unit bolt torque

S

sjaltobelli

Cadet
Joined
Feb 10, 2009
Messages
13
Does any one know how much to torque the bolts that hold on the lower unit? I have a 90 hp 1990 force engine. There are 6 bolts visible and one hidden under the trim tab. Also, how to I index the trim tab? Is it just guess and check? Thanks for any help.
 
a1machinista1

a1machinista1

Seaman
Joined
Oct 30, 2008
Messages
66
Re: 1990 90hp Lower unit bolt torque

I cant find a factory spec for that either. What sealant are you going to use? Do you have a picture of your powerhead?? I need to see where a few things go. Those are 3/8th bolts arent they?? If so I would go 25 lbs with a thread sealant... 32 lbs if you are just going to oil the threads (not sure what it calls for)
 
Frank Acampora

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: 1990 90hp Lower unit bolt torque

Standard torque for a 5/16 X 18 bolt (1/2 inch head) is 160 INCH pounds. Use inch pounds as it is more accurate than foot pounds. Note that the grade 8 head bolts are the same size and the aluminum block will tolerater 220-230 inch pounds. However, the lower unit bolts are stainless and NOT grade 8 so I would not trust them that high.
 
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