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Mercury 800 Power Trim Installation

E

eddiesweber

New member
I am trying to replace my manual tilt on a 1979 Mercury 800 with a power trim tilt from the same era. It has 4 hoses, 2 cylinders and a pump. I bench tested it already and it is operating fine.
 s-l1600.jpg

I am now trying to install the new power cylinders and I wanted to make sure I am taking the right stuff off the old manual system.

First, there is a hole in the side of the power trim base plate and I am assuming it slips over the post that the top of the manual trim was attached to.
IMG_1987.jpg

Next, it looks like I need to remove the lower post on the lower end of the mounting bracket on the engine, where the bottom of the old cylinder used to connect . I am assuming I need to remove small nut and bolt that is located on the outer side of the bracket towards the middle. My problem is that the nut and bolt a very rusted and hard to get off and I feel like I am going to strip the top of the bolt or break it off.
IMG_1986.JPG

Before I continued, I was hoping someone would tell me if I am on the right track and if I do need to remove the lower post and the nut and bolt I mentioned. Also, is there anything else I need to remove? Any tips would be much appreciated!! I have searched all over I can't find anything on the subject. I'll try to do a video of the project once I figure out the process.

Thanks in advance
 
You are fortunate that Quicksilver supplied you with the necessary details.

You are wise to be concerned about the nut resisting removal with the age of your engine and especially if used in salt water. Even though most connections are stainless steel that significantly resists corrosion you still have to deal with it. A thorough soaking with Kroil or PB Blaster (brands) penetrating oils will help. Impact has always worked for me when nuts are frozen on old farm equipment. If you don't have an impact wrench/tool I use a 2-4# maul on the end of a wrench on the nut....whacks while you hold pressure on the nut....aka "impact". If you impact with a ½" drive, 800+ ft-lb unit, for 15 seconds solid, and no results, time for Plan B.

Plan B: If that doesn't work heat is sometimes used but you have to select your uses by what is in the general area that could be damaged by applying heat. When all that fails, take a grinder to the nut and grind down to the "bolt's" threads. Soak that area good and back on with a suitable wrench...a pipe wrench is good for such instances.
 
You don't have to remove the lower mount just take the SS parts out of the ram. The pump mounting bracket is missing in your 1st picture, if you have to make one here's a pattern.
PT-bracketposting.jpg
 
Thanks for the speedy response guys, I'm headed out to give it a try. Your tips and manual are much appreciated. I actually bought the manual for the engine, but it doesn't explain much for my type of power trim, so the manual pages will help a lot.
 
Couple more pointers: Mercury PTT fluid is available at Walmart here. Manual says that regular automotive automatic transmission fluid is a suitable substitute if unavailable. Full on my engines was fluid even with the fill hole. Burping after installation/filling is just powering up-down etc. etc. etc. till you get the bubbles worked out and get it to power all the way up and down. Don't forget to top off fluid as required.
 
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