Tilt/trim question

[CBINMN]

J75trlcsa 1980 75 hp johnson
I do have factory manual.

Complete powerhead rebuild, carbs,water pump. runs great in barrel. went to lake to test an would not tilt down. I have tilted up and down with no problems until I got it to the lake.Up works as it is supposed to bu down the motor runs but nomovement. I used manual release to get it down to trim rams so I could at least set the idle in gear in the water and checked timing. Since I couldn't get it to trim down I loaded it up and brought it home and checked fluid level, tilted up with switch and lowered with manual release several times. still motor runs for down but no movement. Fast forward to this morning: hit the trim down and it worked. went up and down several timesand checked fluid. tilte it up to put transom saver on and it wouldnt go down again. I believe it is only when I tilt it up to the max position and it stops that causes it to not go back down because that is the only time it does this. If I stop before it tops out it will go back down. It also did have a litle bit of a jerk to it when going down from almost fully up down to trim rams. Any suggestions to narrow this down for me?

 

[littletunny]

Re: Tilt/trim question

Dont trim all the way up. That should solve your problem.

I bet you your pressure relief poppet is sticking. It prevents over pressurization of the cylinder when the ram is fully extended.

This picture is not the best but you can see the orange dot at the top of the piston assembly. When the ram is fully extended, this orange button is pushed in and allows fluid to bypass from the bottom of the cylinder to the top of the cylinder. There is a spring under there.

It sounds like your opens but doesn't close. It make need to be dissassembled and cleaned.

OR it could be a dirty shuttle valve.

 

[CBINMN]

Re: Tilt/trim question

Thanks littletunny,
I had planned on not tilting all the way for time being.
The manual I have doesn't mention a shuttle valve. The valve it mentions for stuck full tilt is the expansion relief valve located under motor assembly. Is that the same one?

Chris

 

[littletunny]

Re: Tilt/trim question

No. The shuttle valve I was referring to was part # 0323848 on

http://shop2.evinrude.com/ext/index.aspx?s1=a1ec046b7325b7e44a00ad33dda87454

But, the more I think about the more I think it is not your shuttle valve but the expansion relief valve.

 

[CBINMN]

Re: Tilt/trim question

Would that be numbers 34,36,37 from that diagram or 5 thru 10. Also is there anything else you would recommend replacing in that area while I have it apart? This hydraulics is a bit confusing to me right now but then again so was the powerhead before I started it. Thanks for your help.

Chris

 

[littletunny]

Re: Tilt/trim question

I think its item #11. If the seals arent leaking, you probably just need a dissassembly and cleaning.

Just be careful when dissassembling the piston assembly. It has a bunch of 3/16" SS ball bearings that like to run off!.

If you can work on the powerhead you can definately work on the tilt trim.

Let me know if I can help. I just got done rebuilding a 48 special and know all the pitfalls!

 

[CBINMN]

Re: Tilt/trim question

But, the more I think about the more I think it is not your shuttle valve but the expansion relief valve.

#11 is shuttle valve right?

Chris

 

[littletunny]

Re: Tilt/trim question

My last post was confusing. The shuttle valve is #11 in the parts diagram.

However your problem I believe lies in the pressure relief valve NOT the shuttle valve so forget I even mentioned the shuttle. Just purge it from your memory.

The pressure relief valve is part of the "piston assembly", the orange blip on my pic.

It doesn't show up on the parts diagram.

I would break the unit down and see if the spring and poppet are stuck open.

 

[CBINMN]

Re: Tilt/trim question

Consider it purged.
I will tear it down and check the relief valve.

Thanks

Chris

 

[CBINMN]

Re: Tilt/trim question

Well it's been very busy at work so I just went to buy proper tools to tear it down. The gentleman asked what I was doing, I told him and he said he had a blown powerhead 70 hp 1993. He ended up GIVING me the t/t unit, and all wiring. So needless to say I won't be digging into the old one. The boating community is the greatest.