1977 Johsnon 115ETL77S power tilt issue (Prestolite)

Hi Guys,

My first post all the way from Australia, firstly wanted to say what a great site this has been for me as I'm currently trying to recommission my 1977 115hp V4 Johnson. I've found countless answers to problems encountered already and now need a little more help!

I recently discovered while changing the fluid in the power tilt and trim unit, which is a prestolite variant, that during the obligatory 3 cycles after top up, it wouldn't come down from the very top. I now have the motor fully trimmed up and it wont come back down. I can hear the little motor trying to work and when i hold the down switch for a few seconds i can hear what sounds like it slowly winding or possibly free spooling? I dont press it for too long since I dont want to do any damage.

What I've concluded so far is that the problem isnt in the switch or relay since I can hear the trim motor trying to work. The battery is a fully charged optima D34m (700 CCA), and I have not found any leaks in the unit so far. The reason I drained and topped up the system was because it was having a hard time trimming in either direction and wasn't smooth.

Is it possible that it is just stuck and needs someone to put weight on it while i attempt to trim it down? I havent tried this yet but didn't want to damage anything if that was a bad idea.

I have the workshop manual and have been looking through it for answers but it is a little vague and hints at a check valve being the issue, but doesnt tell me how to fix it!

any help you guys can provide is much appreciated, i understand this particular model of motor and pt&t is quite rare so I'm running out of ideas!

Thanks,
Matt

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

Try cracking open the manual bypass valve and let it all the way down and see if it will raise and lower properly.

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

Ah yes, the manual control valve. I forgot to mention that the valve bolt head has been stripped and there is no way to turn it. It's only a tiny screw and I noticed that it had been damaged the other night. I'm thinking i'll need to extract it and put in a new one but I'm a little worried about what will happen if i botch it up! Hopefully i can order a replacement valve easily?

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

It looks like they are still available.
http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

Daviet said:

It looks like they are still available.
http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ

Click to expand...

It's part number 96 that i need, and it would seem it isn't available unless im mistaken.

Can we assume the manual relief valve is set ok since it tilted up fine?

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

Sorry, I was looking at the CALCO pump parts.
Do you have any salvage yards in your area that you might be able to find a used one?
The manual releif valve is OK because it sealed off the system to allow it to raise. If you could crack it open it would bypass fluid and allow the engine to tilt down.

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

Thanks for the input, i will try to extract the valve. Do you think this would this solve the occurence of this in the first place? Any idea what the root cause might be?

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

I am not sure what caused the problem for sure. I was thinking that if the pump was air locked, by lowering it manually it might get rid of the air in the system.

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

OK Cool, so i'll give that a shot, before i do, is it worth me getting someone to push the motor down while i try to trim down? or will that cause damage?

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

You can try it, just don't get to heavy handed with it.

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

Daviet said:

You can try it, just don't get to heavy handed with it.

Click to expand...

With a bit of a push it went down just fine, i cycled it up and down without any pushing 3 times and now its fine again. Thanks for your help!

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

Must have been air locked, glad you got it working properly.

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

So why does that happen daviet? Could it have happened when i was topping up the reservoir? I might have operated the switch when the filler plug was still open, i read somewhere that this is a good way to ensure that you fill up the reservoir at the top, but could this be what brought air into the system?

Re: 1977 Johsnon 115ETL77S power tilt issue (Prestolite)

Can't tell you why, sometimes they just do it. At least you know what to try the next time it happens.