1987 force 85 horse trim slips off thrust bracket

[patrickj]

Ive been screwing around with my tilt n trim getting things worked out and i recently learned that when im in the water i have no trim, so i tested it on the trailer and when the motor comes down and touches the thrust plate against the trim motor, the trim motor tilts up ward and slips off the thrust plate. So i bought a piece of angle iron and cut it to fit and it owuld stay on it until it bent the bolts...long story... anyways the question is why is the trim motor lifting, i can move it by hand and i see nothing that would keep it from moving.


I thougth about buying some tree falling wedges and hammering them between my transom and the trim motor to keep it from moving.

 

[jerryjerry05]

Re: 1987 force 85 horse trim slips off thrust bracket

pics??

 

[Frank Acampora]

Re: 1987 force 85 horse trim slips off thrust bracket



First be certain that the stainless plate is screwed to the yoke where the trim ram contacts it. This plate is an odd shape and secured with two screws.

Second, cut a piece of hard aluminum (aircraft) about 1/8 thick to about 13 X 16 inches and put it on the outside of the transom under the clamps. The primary reason your trim ram is slipping off its contact pad is because your transom is worn or spongy allowing the whole trim cylinder to tilt as it functions. It was designed to sit flat against the transom. Seriously consider probing and repairing the transom. It may be completely spongy and/or rotten. Check to be sure the trim cylinder is not corroded solidly in place and can pivot on the bar. If it is jammed in the up position, that is, tilted so it will not contact the stainless pad, free it--not an easy job.

As you can see, I plate all my boat's transoms, whether they need it or not.

In the interim, since you have no trim adjustment the engine is likely to be tucked all the way in. Until you correct the problem, since a bar will not fit across because the trim cylinder is in the way, put two long stainless 1/2 inch bolts and nuts through the set of holes in the transom clamps that put the engine closest to parallel with the bottom of the hull or whichever set gives most speed for you. Your tilt function will still work. Use the first photo as an example.

 

[patrickj]

Re: 1987 force 85 horse trim slips off thrust bracket



Ok here is a couple pictures. In the first picture the trim motor is in its correct position, second picture its lifted about 3 inches.

Frank... as for the trim motor laying flat against the transom... this isnt the original motor to the boat and this trim motor doesnt even get close to touching the transom i can slide my 4 fingers behind the trim ram so this is why its tilting... my tansom is solid as a rock its already been braced. i think a solution may be to wedge something behind the trim ram to give it support against the transom.

 

[patrickj]

Re: 1987 force 85 horse trim slips off thrust bracket

ok i re-read what you said frank, your talking baout putting a piece of aircraft grade aluminum big enough to cover basicly the whole transom to support the clamps at the top and the lower bolt holes correct? any idea where i can pick up a piece of aluminum that large?

 

[Frank Acampora]

Re: 1987 force 85 horse trim slips off thrust bracket



It need not cover the whole transom although a couple of min nearly do--overkill-- It just needs to have enough width to allow the transom clamps to spread out the pressure. So, about 13-14 inches deep to account for the bottom bolt holes and 15-16 inches wide to have some extra outside the clamps. Then, if there is still room behind the trim cylinder, You can slip in another thickness there, between the clamps. I have never needed to do that though.

Almost every town in the US has a fabricator or welding shop. Little Rock, being a city most certainly has a number of them. You should be able to buy a new piece there. Salvage yards will sell you scraps if you can find a piece big enough.

Please do not make the mistake of using diamond plate. It is actually soft and weaker than hard aluminum.

And if you have a friend at the D.O.T. bent and unuseable traffic signs are great if you can salvage a large enough piece.

Note how in all photos the trim assembly sits flat against the aluminum. Note also the photo with the bent stainless pad.

Looking at your photos closer, it appears that someone had installed spacer plates under the bottom of the transom clamps. If this is correct, then that is the root of the problem. However, I still recommend installing a plate. It takes abuse much better than fiberglass and spreads the loar of the transom clamps.

 

[RRitt]

Re: 1987 force 85 horse trim slips off thrust bracket

The back of your trim housing has to fit flush against the transom. The transom keeps the housing from shifting too far. The trim housing shoudl have no more than 1/8" of play behind it. If there is too much play the trim psiton will slide of the bracket pad ( a stainless steel "U" shaped shoe ). In time the trim piston could split your aluminum swivel bracket.

As regards your picture, the trim cover is missing a critical piece. If you operate without the centering ring and seal then you are getting water into the system.