Early 70's Mercury 850 85 HP

[JHeheman]

Late last year while putting my boat on the trailor the prop hit the ramp. OUCH! Now reverse on my Mercury 850 (85hp) no longer works. The shifter seems to be fine. Did I spin a gear? Any help would be appreciated.

 

[mellowyellow]

Re: Early 70's Mercury 850 85 HP

welcome aboard,<br />remove shift cable and try to shift manually.<br />if still won't go into reverse, gonna have to<br />drop lower unit to check. was prop engaged when<br />u hit? could be the cluth dog also.<br />good luck,<br />M.Y.

 

[JHeheman]

Re: Early 70's Mercury 850 85 HP

Yeah the prop was engaged, I was trying to move the boat forward on the trailer. Clutch dog?

 

[The Marine Doctor]

Re: Early 70's Mercury 850 85 HP

Disconnect the shifter cable at the engine.<br /><br />Push the Linkage all the way to the back of the engine. See if REV engages.<br /><br />Remove the prop...check to see that the Brg Carrier has not been pushed out. There will be a large Ring Nut that may have to be turned clockwise to retighten the brg carrier. This will move the Rev gear closer to the clutch again.<br /><br />TMD

 

[JHeheman]

Re: Early 70's Mercury 850 85 HP

Thanks! I'll give that a try.

 

[JHeheman]

Re: Early 70's Mercury 850 85 HP

Well I checked the bearing carrier and the large ring nut and that all looks good,not pushed out, (I could only tightened it about 1/4 turn, no help). Can I pull the bearing carrier out without dropping the lower unit? Am I going to need a special puller as my manual states? I'm thinking the reverse gear is shot or the slip clutch has a problem.

 

[mellowyellow]

Re: Early 70's Mercury 850 85 HP

remove the cables and try to shift manually!

 

[JHeheman]

Re: Early 70's Mercury 850 85 HP

Cables removed, still no reverse!

 

[The Marine Doctor]

Re: Early 70's Mercury 850 85 HP

yes...you can pull the Brg carrier out without removing the gearcase.<br /><br />Check for wear on the cam and shifter pin.<br /><br />TMD

 

[JHeheman]

Re: Early 70's Mercury 850 85 HP

Removed the l/u last night, it had more water than lube in the l/u. Trying to find a puller to get the bearing carrier out. Should I replace all seals on this unit since I can't tell where the water leaked in? Any commom seals known for leaking on this unit. Mercury 850 85 HP ser. #3877318 TIA

 

[The Marine Doctor]

Re: Early 70's Mercury 850 85 HP

Yes its best to replace them all and rebuild any worn or rusty shafts.<br /><br />TMD

 

[JHeheman]

Re: Early 70's Mercury 850 85 HP

First, thanks to all who replied in helping me get my reverse(brakes!) back. To the Marine Doctor, you were right, over the years this motor had water in the l/u and had pushed the bearing carrier out and the threads(on the l/u housing) are marginal. Could not tell until I pulled everything apart. All the gears and clutch look to be in good shape. Question, after I get the bearing carrier back in to where it's supposed to be, can I drill into the l/u and into the outer ring of the bearing carrier and put set screws(and sealing them) in to help keep the ring nut and carrier firmly in place? I'm also wondering how to tell when I have the clutch centered between the forward and reverse gears when in neutral. Anyway, off to ordering seals and a water pump kit. Thanks again

 

[wrxcobra]

Re: Early 70's Mercury 850 85 HP

Hi JHeheman
I also have a 85 blue band but am having trouble finding is year as the id plate fell of years ago, would you have a photo of yours and do you know the year, to give me some idea if they are the same.
how long have you owned this motor and how happy are you with it, mine is my dads and have owned it since 1980 its been great only showing some minor problems know.
Daniel thanks

 

[roger3645]

Re: Early 70's Mercury 850 85 HP

I have 2 of those, a 1973 and 1975 850, had the same problem with the treads in the LU, and yes I used set screws just as you described. As far as your leaking LU goes: Take a good look at your drive shaft, especially in the areas were the seals of the water pump base go. If it is rusty and pitted, it just won't seal, you'll need to put a speedi sleeve over it. I had too and it worked great. Once you get your LU back together with the new seals, you can pressure test the unit with air. If it will hold 10lbs of pressure it is good.

This is my way: I take the hand pump you use to pump new oil into the LU. Connect it to the LU drain hole and blow air into it. If it fills with air and difficult to blow into it's good. If it don't hold pressure then it's going to leak. You can do this with the LU underwater and see where the air bubbles come from. This will give you an idea of where it's leaking from.