1974 Mercury 850 problems

[SS Ice Cream Paint Job]

Hey guys first post here and cannot wait to see where the guru's are. Anyway I did a exterior remodel for a 92 y/o man in New Orleans and got to be buddies. He had this old boat in the yard and getting in the way so he gave it to me. The boats is a 1973 vbow (no name anywhere) and the motor is a 1974 Mercury 850 thunderbolt. The guy had not used the boat in over 10 years and it had been sitting in working condition. When i try to get the motor to raise up with the tilt it clicks loud when i press the up but i hear it pumping when i press down. The motor is already all the way down. I cleaned the piston or whatever the shiny part of the tilt is with an emory cloth before i tried to mover it. Any tips? The battery is brand new and starts the motor just fine. Another prob is that the motor doesnt pump the water out of the pee hole. Im sure it needs a new impeller but is there anything else i should change while im down there?? Also what needs to be changed out when a boat has been sitting for so long. We got the boat running within minutes and it idles goes forward reverse and everything. Anyway any tips would be great. Im trying to get my freebee seaworthy. Randy

 

[nubbie]

Re: 1974 Mercury 850 problems

Is the tilt/trim pump mounted inside the boat ? if so does it have a red plug that's plugged into the pump coming from the control box? I think it has a green wire, yellow wire, and a light blue wire.

As for the water pump...Change it.. It will only bring more trouble, its old and dry rotted by now (10 years)..

The pee hole...Take the hose off from the engine side carefully.. try to blow air or water from a garden hose through it..I'm from N.O. and dirt divers always seem to make a home on the inside of the hose (on outside of the motor)..

If it runs that a good find...If Your using the fuel hose that came with the boat,,Go buy a new one ...Wal-mart or Academy sports should have one. The old one will fall apart and get in the carbs, and then you'll have a new problem..

We'll start here..
Tim

 

[nubbie]

Re: 1974 Mercury 850 problems

Also if You cleaned the chrome looking things, that's the ram for the tilt/trim wipe them down just this once with some motor oil, so the seals dont get destroyed being there dry for there first movement..

 

[SS Ice Cream Paint Job]

Re: 1974 Mercury 850 problems

Thanks for the advice man. The pump is on the inside and under the i guess second transom. the boat is clean, the floor i kinda soft. i just know that the trim is going to be some $. So if its just clicking t you think the connection is bad? Is there a lock on the motor to where i cont go up or down? because its really not a knock or click its more of a thud. like its getting alot of power to move it but no movement. I appreciate your time. Any those mud divers can be anywhere on this old girl!.

 

[nubbie]

Re: 1974 Mercury 850 problems

This sounds crazy...but...put the shifter in forward and try to use the tilt to go up.

 

[SS Ice Cream Paint Job]

Re: 1974 Mercury 850 problems

Alright I got the pump working, it leaks a bit but it works. Not to get her running. What is the oil:gas ratio? Another thing when we were messing with the trim pump we notices a wire that was crumbling away. If you are looking at the motor from inside the boat it is a wire on the left side that goes into the mounting part of the outboard in front of one of the pistons for the trim. Any ideas? The wire is two wires in rubber and then it splits inot two different single plugs under my second trasom. Thanks guys