Yamaha Tilt/Trim Manual Relief Screw

[jfbetz01]

Can someone tell me what in THE hell Yamaha was thinking when designing this screw? For slipped boats, this screw sits in water. Did the brain trust at Yamaha really think a slotted screw driver could develop enough torque to actually turn this screw?

I recently lost one of my tilt/trim units on my port ox66 250. The engine was locked in the down position, so removal of the unit was problematic. Since the unit was toast, I ended up drilling a pilot hole in the screw to relieve pressure and raise the engine to pull the unit out. Fortunately, I had a spare unit from an old engine; its fully operational, but has the same problem with the screw-wont budge with a slotted screw driver. Any magic tricks on loosening these screws?

[99yam40]

Manual impact screw driver

[99yam40]

pay attention to which way you are trying to turn it

[jfbetz01]

Impact screw driver made things worse...the aluminum alloy is too soft for a slotted impact. Tapped with a hammer, used some heat/pb blaster. Just a poor design. And yes...turning in the correct direction towards "manual tilt".

[99yam40]

what kind of impact where you using?

[pstephens46]

Doubt the screw is aluminum alloy, who knows?

What is a slotted impact driver?

Impact driver has worked well for me. That screw, l/u drains and even the crappy little vst screws. The bit needs to
fit as tight as possible while extending fully into head of screw. Then smack the sht outta it....

I would not want to do this hanging off the back of transom with boat in water.

[panasonic]

Can someone tell me what in THE hell Yamaha was thinking when designing this screw? For slipped boats, this screw sits in water. Did the brain trust at Yamaha really think a slotted screw driver could develop enough torque to actually turn this screw?

I recently lost one of my tilt/trim units on my port ox66 250. The engine was locked in the down position, so removal of the unit was problematic. Since the unit was toast, I ended up drilling a pilot hole in the screw to relieve pressure and raise the engine to pull the unit out. Fortunately, I had a spare unit from an old engine; its fully operational, but has the same problem with the screw-wont budge with a slotted screw driver. Any magic tricks on loosening these screws?

I agree with you on the slotted screws....just crap. With all the fasteners available today they should change to a Allen head screw. Along with the LU unit drain screws..would be much better.

Got be careful with manual impact drivers they can easily be set to tighten when you think its in the loosen direction. I learned a long time ago to always push the driver against something and watch the bit to see if it is turning the right way.

Also sometimes after one or more smacks with the hammer they can pop back to the opposite direction as well... Not saying that is what you done...just saying for others who may read this post.

[boscoe99]

The location is not just on a Yamaha. They are all like this. It is the nature of the beast.

Yes, would be nice if the screw was an internal hex.

Now God forbid that anyone actually unscrew and then retighten the relief valve screw on a periodic basis, say yearly, so that it can be readily unscrewed if and as needed. Nope. Let it sit unused in the briney blue for a decade or more and then complain about how difficult it is to loosen.

Better to curse the darkness I suppose instead of lighting the candle.

[99yam40]

.
we have no idea if he used a manual or even knows what a manual impact is.
have you ever had to clean out a alen head socket full of corrosion or other things to get a wrench in it properly.
kind of a pain, a slot is easy.
exercising the fastener from time to time may help

[scofflaw]

Crack open the easily accessible line at the bottom of the unit. PO had totally destroyed the slot on mine. Made a new slot with a hack saw when I got it in the vise