Yamaha F100 slowly drops by itself!

kkilloy

Seaman Apprentice
Joined
Oct 10, 2004
Messages
32
I fished Saturday and the tilt/trim worked. On Sunday I noticed that the tilt indicator showed the engine was all the way down. I trimmed the engine up a few inches and within 30 seconds it went all the way down again. I does this running or sitting (engine on or off). I checked oil level and it was full. Any suggestions are appreciated.<br /><br />Thanks, <br /><br />Kevin
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Yamaha F100 slowly drops by itself!

hello<br /> could be a number of things. from a bad oring on the manual release to a bad main valve in the pump assy. no good way to tell without some special tools that are not avalible to the average joe. they are available but expensive. be aware that most techs dont have a clue when it comes to the hydraulics, most want to replace the unit. its expensive. I would reccomend purchasing the F100 service manual and familairize yourself with the hydraulics.
 

kkilloy

Seaman Apprentice
Joined
Oct 10, 2004
Messages
32
Re: Yamaha F100 slowly drops by itself!

Thanks for the suggestions. My engine is a 1999 F100. Which manual do you suggest I purchase? One manual that I see for sale covers 2000-2003 or 04. Will this work with my 1999 engine? Thanks again for all the great advise.<br /><br />Kevin
 

kkilloy

Seaman Apprentice
Joined
Oct 10, 2004
Messages
32
Re: Yamaha F100 slowly drops by itself!

I ordered the Clymer book on the motor. A rebuild kit is not available from Yamaha. I took the tilt/trim unit apart, drained and blew it out with compressed air, refilled with dextron III ATF fluid per the book and it is working perfectly. Thanks for your help.<br /><br />Kevin
 
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