99 35hp Johnson trim/tilt noise

[jeffkrol]

Well end of the season here and things went well EXCEPT right at the end the trim/tilt started to make a "thump"thump"thump" noise on lowering the motor. Up is fine.
Is this anything simple or major? Also one little annoyance is that the trim/tilt guage has a lag. Needle will remain in a position and then jump up. Also an easy fix?

 

[RRitt]

Re: 99 35hp Johnson trim/tilt noise

I usually see that only at the very top of stroke when a system is beginning to wear out or is a new rebuild that has not yet been cycled and filled. What happens is that it runs out of fluid at the very top of stroke and pumps in air bubbles. As the system lowers, the piston shaft displaces fluid and the thumping stops as soon as the pump gears are fully submerged.

Lift you system all the way up and then check fluid levels. It should be topped off to bottom of filler when the system is fully raised. Do not attempt to check or fill fluid levels without first fully raising the engine.

If the system is low on fluid then you have a rebuild in your future. Oil does not magically disappear. You can extend the life of your system by bracing it when not in use. Bump the switch just enough to let the pressure off and allow motor to rest against brace instead of trim piston. Bracing engine on trailer and storage can double life-span of trim.