Still Leaking T&Trim seals on 2005 250 4 strokes

[mailman1]

I have replaced the dust covers and cylinder caps and the "o" rings on the caps and 3 of the 6 cylinders are still leaking!!
Towards the bottom of the piston there is another "o" ring and a white split ring as well. Should I replace them as well?
Finally, do the dust covers actually stop the fluid from leaking out or are they just "dust covers"?

[fairdeal]

how is the surface finish of the rams?

if you have "pitting", that will allow oil to "sneak out" under the seal
and if its rough enough, will "chew up" a new seal

for the trim rams, there is only one seal, so it has to function both as main oil seal and "wiper"

seems odd to call it "SEAL,TRIM DUST"

"inscrutably" on the tilt ram, where there is ALSO an internal oil seal (o-ring) the outer wiper is called "oil seal"

it appears to me another example of strange Yamaha nomenclature...

[99yam40]

dust covers are suppose to help keep the out side stuff from going in , not keep oil in

[fairdeal]

dust covers are suppose to help keep the out side stuff from going in , not keep oil in

From a dictionary standpoint, sure. But when there is only one part..



Interestingly, although the parts fiche calls it "seal, trim dust"

the service manual more sensibly calls it "oil seal"

[mailman1]

Thanks for your help

Thanks for your help!!! It seems that a leak in the trim or tilt can happen almost with a weather temp change?
I never imagined how sensitive that whole system is!!!!
I purchased a Yamaha Service Manual for my motors and that was a mistake as well. The pictures are too blurred to see some things like which way to put the cap seals in??? how to get the tilt ram apart to replace the cap o rings.
Does anyone know a publication for Yamaha that shows clear pictures and exact steps to fix Yamaha Motors????

[rodbolt17]

its fairly simple.
just need to know the difference between a push down system and a pull down system.

in the above picture its a pull down system and all that dust wiper does is prevent oil seepage out and water and dust seepage in.

its NOT designed to have ANY pressure in the chamber between the piston orings and the wiper seal.

means the piston orings are not sealing.

did you evacuate the fluid from the chamber and inspect the cyl walls?

did you replace the piston orings?

this I see every week, its not the wiper that went bad yet its the only seal that gets changed.

a quick way to tell if the system your working on uses hydraulic fluid under pressure is to simply look at the drawing.

if the cap has an oring that fits around the piston shaft its a pressure down system.

if the cap has only a dust wiper its a pull down.
see how easy this stuff is?

[mailman1]

Thanks rodbolt17!!!!
Where are you getting the Pics from......What Manual??
The Tilt assembly that I have has a biscuit looking thing that unscrews off of the piston. I had to use a pipe wrench to get it off the shaft.
I ended up with burrs on the biscuit looking thing that has springs and shafts in the holes provided. Does that biscuit have to be replaced now as well??

[TownsendsFJR1300]

For the pic's, if you look up and to the right on THIS PAGE, you'll see in RED, "Purchase Yamaha Parts".

Click on that, click on your engine year, model, etc and its the same. You can zoom in on it.

The pic above was likely taken there,

You can also "snip it", then up-load to Photobucket and post larger here..

[mailman1]

Thanks Scott!! I am amazed as to how expensive Tilt and Trim stuff is!!!!
I just ordered the assembly for 1 Tilt system on one motor.....$496.00

[TownsendsFJR1300]

Thanks Scott!! I am amazed as to how expensive Tilt and Trim stuff is!!!!
I just ordered the assembly for 1 Tilt system on one motor.....$496.00

If it says Genuine Yamaha, its expensive.

If its marine related, multiply the cost times THREE...


However, I would buy the OEM before a Chinese knock off (for less the price)...

[TownsendsFJR1300]

I was referring to Yamaha Specific products, but yes, they screw you for "marine" as well...

With that said, in most cases, you can feel, see the better quality in an OEM product than aftermarket...

[mailman1]

another $864 for the same Tilt and Trim......... There was NO way to take the piston off the shaft of the tilt assembly without scoring it with a adjustable wrench!!!!! :-(
B O A T?

[Nautical]

if you look at item #8 in the diagram which is the tilt , but reference the trim diagram that is what keeps the oil in and that is what goes bad or wears out when you see an oil leak at the cap.If you replace that seal (its expensive) make sure you face the cup down when you install it in its seat otherwise you will have a leak even with the new seal.I dont think the teflon backer needs to be replaced as it does not wear per se.

[99yam40]

another $864 for the same Tilt and Trim......... There was NO way to take the piston off the shaft of the tilt assembly without scoring it with a adjustable wrench!!!!! :-(
B O A T?

I have a feeling Yamaha has special tools for taking them apart to keep from damaging the parts

[rodbolt17]

Yamaha does not sell common sense.
common sense dictates NEVER EVER NEVER, did I say NEVER?
NEVER twist on any hydraulic parts with ANY jawed tool.
the result is a destruction of the part.
IF the OP actcually reinstalled that destroyed part it most likely now has destroyed the cyl as the burrs on the piston will scar the bore.

how I do it is remove the tilt piston assy.
lock the pin anchor end in a vice.
use the correct torx bit and remove the plate.
carefully dump the springs,balls and pins on a clean cloth.
reanchor the tilt piston in a vice by the tilt anchor end.

use two pieces of 8mm rod and a screw driver and unthread the piston from the rod.
then you can remove the cap.
if you do a couple thousand over about 20 yrs its actually easy.
but the manual is fairly vague about it.