Trim motor question

[bones1966]

I have just replaced trim motor on 2001 tlrz 70 hp. I have tightened the mounting bolts but am stii getting fluid leaking from around the base of new trim motor. Btw new trim motor is an after-market. Any ideas? Are the bolts supposed to be torqued to a specific value?

[DennisG01]

It seals with an o-ring, right? I'm sure there's a torque value, but it won't be anything special since it's an o-ring. Check your service manual, though, if you want. Tightening evenly is probably more important than the exact torque value. When you put the new motor in, maybe you misaligned the o-ring? Unless the mating surface(s) around the o-ring are corroded? How did it look?

[bones1966]

Yes, it seals with o ring. Don't have service manual. Was very patient and kept tightening slowly. That is one thing I was wondering about. O-ring just slips onto base of motor, not really big enough to slide off on its own. No corrosion to speak of. sysem was pretty clean and had plenty of fluid. Maybe not tight enough, didn't want to strip or snap a bolt off.

[DennisG01]

They're pretty small bolts so it really wouldn't take much. You should pretty much be able to tell by feel when it's snug enough.

[TownsendsFJR1300]

Did you replace the sealing o-ring? If not, it should be...

The parts diagram shows one seal (PART #28): https://www.boats.net/catalog/yamaha...trim-tilt-assy


Rubber hardens up, flattens over time allowing leaks / failure


As for tightness, good and snug should be plenty...

[rejesterd]

These are the torque specs from a 1999 70hp service manual:

https://imgur.com/a/XgTSrSA

With o-rings and rubber gaskets, you can't go too tight.

[fairdeal]

Bolt torque is a non-issue in this situation.

Once the two metal mating surfaces -
the motor and the t/t casing -
are flat against each other,
tightening the little bolts more can do nothing - other than snap them.

Are you sure its a "leak" and not just a bit of residual fluid oozing out?

[FabricGATOR]

I was thinking that perhaps the mating surface on the counterfeit trim motor may have a flaw. Maybe where a seam from the manufacture molds come together??? The quality control may not be as diligent.

As fairdeal said, 'residual fluid' seeping from the seam is great possibility too.

I would guestimate the torque being somewhere in the 50 to 80 inch pounds.

I had to look, and while I don't have FSM handy, I found this https://www.engineersedge.com/torque_table_sae.htm
Using 1/4"- 20, in aluminum it shows 45.6 inch lbs.... So 50 inch lbs or 4 ft lbs.

Over torque will cause the plastic motor housing to crack at the mounting holes in a few years.
I'd recommend TefGel on the threads for future fastener removal too.

[99yam40]

With o-rings and rubber gaskets, you can't go too tight.

this is so wrong

[FabricGATOR]

I see rejestered had better info.... 'Gear pump Mounting' ? Is that it? So 3 or 4 Ft lbs depending on model, not very much....

Inspect the sealing surfaces where the o-ring is supposed to do its job, and use only a new o-ring (can lubricate it in the hydraulic fluid)

Give it a cleaning with aerosol brake cleaner or electrical contact cleaner (even mild soapy water and low pressure rinse) and watch to see exactly where the seep is coming from. Maybe the new motor leaks?

[rejesterd]

this is so wrong

Not if you read what I was saying correctly.

[DennisG01]

Not if you read what I was saying correctly.

99Yam is correct. Your choice of words is incorrect. What you probably meant to say is "You shouldn't go to tight".

"I can't get enough hugs from my kids" = The more hugs the better.

"You can't go too tight" = The tighter the better.

[bones1966]

Thanks to all of you. Appreciate the info. Found the problem, the after market trim motor came with an o-ring of considerably smaller diameter of cross section, i. e thinner than original. Believe that was the problem. Had the bolts sufficiently tight. Problem has been resolved.Thanks again to all for helpful input.
Regards, Bones

[FabricGATOR]

Thanks to all of you. Appreciate the info. Found the problem, the after market trim motor came with an o-ring of considerably smaller diameter of cross section, i. e thinner than original. Believe that was the problem. Had the bolts sufficiently tight. Problem has been resolved.Thanks again to all for helpful input.
Regards, Bones

Hey bones1966,
Great to hear you git R done. Thank you for returning and giving a report and closure.
Now, next time, we can pass on your information and suggest they size up the included o-ring.
Don't be a stranger...
Cheers!

[TownsendsFJR1300]

Plus 1 ^^, tks for the update, nice easy fix...