V4 omc power tilt trim wont stay up

[aaron5705]

I have a 87 110 with power tnt and it works fine in the yard but when i took it out this week for first time with the tnt hooked up it wont trim up under a load. I can slow down to 10mph or so and it will go up but when i hit the throttle it just goes back down. Im guessing its a valve leaking by internally but have never really messed with tnt. Thanks

 

[boobie]

Re: V4 omc power tilt trim wont stay up

First off, how long have you had this mtr? Is this a new prob? Is it just going down to the tilt rams or all the way in to where the mtr is completly down? Does the trim work when under power to trim out the boat?

 

[aaron5705]

Re: V4 omc power tilt trim wont stay up

Ive had the motor for a year but just added the tnt last week. The motor is a 79 100hp and the parts motor i got was a 87 110 which i got the tnt off of. The motor will trim up if im goin 10 -15 mph or slower but not any faster. If i slow down and trim it up as soon as i give it hard throttle it goes down to the tilt rams. I guy at the local marina said there is a handful of valves that could be bad but he didnt really seem to know how to test them or which ones were more likely. Sounded like he just wanted me to buy every valve and replace them

 

[boobie]

Re: V4 omc power tilt trim wont stay up

Now when you are under way does the trim only systerm funuction properly ? IE: bow up,bow down and ect. If it does, two possibilities, either you have some valves in your tilt cyl that are leaking or it is completly normal. When ever you gave these mtrs more throttle when it was in the tilt position they would come down to the trim rams and stay there till you used your trim button. Tilt was for slow speed only and not under power.

 

[ezeke]

Re: V4 omc power tilt trim wont stay up

That's correct, by design, you only have about 15 degrees of trim function that will hold under the pressure of the motor running normally in forward gear.

 

[aaron5705]

Re: V4 omc power tilt trim wont stay up

Thanks for the quick replys. Once i get up to speed it wont trim up or down at all. The rams just give in and thats the only position it has until i slow down. Im trying to figure out what valves i need to order or if there is any way to test them. Could it possibly just be low on fluid? most of the info ive read said when they are low the motor runs for a while before tnt moves. Mine moves the instant i hit the button and functions just like the tnt on my blackmax when they are both in the yard or at idle in water.

 

[boobie]

Re: V4 omc power tilt trim wont stay up

Raise the mtr all the way up and then check the fluid in the unit.This may tell you something. These units can be repaired but to do it properly you need a service manual which has a trouble shooting chart in it and some special pressure gauges to check both the up and down modes. When you have the proper tools and the manual it's not hard at all. But for a one shot deal it's probably to costly. You may be better off just to look for another good used unit.