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Ask Jeff G. Your Own Question
Jeff G.
Jeff G., Marine Mechanic
Category: Boat
Satisfied Customers: 4725
Experience:  42 years experience, Certified Master Technician, All Major Outboards, Sterndrives, Hi-Performance
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Have a 200hp johnson ocean runner 1998 after i get up on plane

Customer Question

Have a 200hp johnson ocean runner 1998 after i get up on plane i trim it up for boat to run smother cross ways by the motor goes back down by it self then i would trim up again and again but still goes down but when boat is on trailer it stays in place what could be problem
Submitted: 2 years ago.
Category: Boat
Expert:  Jeff G. replied 2 years ago.
When on the trailer you only have the weight of the motor pushing down on the hydraulics of the trim. When under way you have the additional force of the engine pushing through the water and the weight of the boat. That's why the up side of trim is as much as 4x as strong as the down side.You have a leak in the system. If there is no evidence of leakage around the trim rams, the rods that push the engine up, then the leak is internal.First thing to do is to open the manual relief valve. This is a slotted valve on the side of the clamp bracket. There will be a recessed hole, use a large screwdriver and turn the slotted valve out no more than about 2 turns. We don't want to damage any O rings.Manually pull up on the lower unit to tilt the engine, then let the engine trim down on it's own. Do this a couple times. Screw the manually relief valve back in until snug, don't over tighten it.What this will do is if there is a tiny piece of debris or the valve is sticking it may allow it to pass or release and the trim to work properly again. It is an inexpensive method that works in most cases where there isn't an internal leak.After tightening the manual relief valve trim the unit all the way up and check the fluid level. The large slotted plug on the back of the trim unit. Fill to overflowing with ATF. Use a squirt oil can or one of those plastic ketchup bottles like at the local diner.After doing all this post back and let me know how you made out. If you have additional questions on this let me know.Thanks
Customer: replied 2 years ago.
Thanks good help
Expert:  Jeff G. replied 2 years ago.
Be sure to let me know how it goes so we can go from there if needed.

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