1973 85 hp mercury outboard needs shift adjustment

I am new to boating an just bought my first project. I have a 16" fiberglass cutter with a 85 HP merc on it, goes into forward no problem but the revserse slips under load. From what I see the cable is not going back far enough to engage reverse fully if i pull the linkage over about 1/4 inch it locks into reverse trying to figure out how to adjust cant find information on the net. Also how do you get to the cable to adjust it i cant seem to drop the housing far enough to get the brass plug from the holder.

Been readin the forums for a bit but cant find my answer. Hopefully someone here can point me in the right direction. Also second problem when i have the boat out it doesnt seem to plane properly it has a manual tilt but not sure which way i should move towards or away from the transome. Also the motor maxes out at 4200 rpm is that normal. The markings on the prop says its a 23 do u think that is the right prop for my boat. Thanks in advance for any help out there.

Re: 1973 85 hp mercury outboard needs help

Re: 1973 85 hp mercury outboard needs help

if its a 23 pitch would be too much for that fiberglass boat, would be more around a 17. 17 3 blade would bring it on plane faster and raised the rpms

Re: 1973 85 hp mercury outboard needs help

Re: 1973 85 hp mercury outboard needs help

Ok thanks will look into that, thanks its a start I am new to boating an that prop came with the boat an motor, so any help is appreciated

Re: 1973 85 hp mercury outboard needs shift adjustment

Any one know how to drop my housing to get to the shift linkage, i dont want to undo the nut incase the bolt drops dont know if it will. Ive undone the 4 bolts at the rear an 2 at the front but doesnt drop enough to get at cables an cant remove the cables to help due to housing holding them in holder im stumped

Re: 1973 85 hp mercury outboard needs shift adjustment

Not sure what you are attempting. The shift and throttle cables are captured in a single holder via the brass barrels. Both barrels are released by a cam type lever. Flip the latch inboard then lift the cover up and over the cables. The brass barrels then will slide out of the holder. Should be no need to remove the cowling if thats what you are aiming to do.

The ends of the two cables are attached differently. Throttle is bolted and the shift cable is captured on a pin and locked under an arm that rotates to lock in place over the cable end.

To adjust the shift points I would think you need to change the position of the brass barrel on the threaded portion of the shift cable. Can't say for sure what direction it needs to go.

Re: 1973 85 hp mercury outboard needs shift adjustment

Nut, You should be able to adjust the shift linkage w/o dropping the gearcase. Set the control handle to neutral. Remove the throttle cable barrel nut and the shift cable barrell nuts from the clamp on the port side of the motor. Now wiggle the shift arm. It should settle into the neutral detent and come to rest. Now adjust the shift barrel nut to fit the clamp.

If that doesn't fix it, you either have a bad control or something wrong in the gearcase.

Re: 1973 85 hp mercury outboard needs shift adjustment

Well thanks for the info , I didnt realize the shift linkage was on a pin with a cover that twisted that was my main concern thought it was a nut an bolt. an the holder had me confused didnt realize it poped up like it does well ive learned alot on here an really appreciate the knowledge that is gven free here.
ive just spent a couple hours outside hopefully adjusting it right, seems to be workin in laneway now gotta wait for the weather to get nicer to put the boat into the water. Im hopin that this fixes my problem cause the nearest repair shop says he wont be able to do anything for 2 weeks. Well wish me luck

Re: 1973 85 hp mercury outboard needs shift adjustment

I have the same sort of problem with my 1975 Mercury 650.

It goes into reverse but when it does it revs as if it was full out but we do not move that fast. Not fast enough to stop forward momentum when heading for the dock.

I have read the adjustment details mentioned here and understand what to do. My question is which of the two cables are the reverse cables that I want to adjust? In my motor they are one on top of the other.

Is there a website that might have pictures or can anyone give me a details on how to adjust the correct cable? :redface: