Help with a '86 Merc. 50HP

[crs0010]

Ive just acquired an older boat with a 86' mercury on it. Brought it home and tried to get it cranked. I know already that the solenoid is bad and will get a new one tomorrow. So to get the starter motor to turn over i by passed it with jumper cables and touched the positive side of the started motor to see if it would turn over. It was struggling very hard to even get a rotation. I took out the spark plugs try and look into the cylinders and then the engine moved much easier, and the starter motor and the rest of the components moved and sounded right, shot a little oil in there and put the plugs back on. Then, back to square one. Hard to turn. Im afraid if i do much more i could burn out the starter motor. Before i do any damage. is there anybody who might be able do diagnose my problem?

 

[Maxz695]

Re: Help with a '86 Merc. 50HP

I would use PB Blaster in the cyclinder first off let it soak overnight longer if possible turn frequently losening up any build up that may be on the rings. continue to turn the motor over without plugs in it to see if the cylinders will free up..

 

[Sunfish12]

Re: Help with a '86 Merc. 50HP

If what Max said doesn't work then you need to clean the starter brushes or send it out for a rebuild

 

[Maxz695]

Re: Help with a '86 Merc. 50HP

the fact that the engine turn fully around without hinderance is a good sign it may be fixable. if you can free it up turning the Flywheel by hand back and forth lubricating the cylinder walls. I would dry out the cylinders then imidiatley have a compression check done

 

[Alumarine]

Re: Help with a '86 Merc. 50HP

If with the sparkplugs in you can turn it over easily by hand, then it's a starter problem.

 

[Maxz695]

Re: Help with a '86 Merc. 50HP

disconnect the spark plug wires with the plugs in it and try again you may be getting pre ingnition due to bad timing as well

 

[crs0010]

Re: Help with a '86 Merc. 50HP

Well thank you guys who posted info. I figured out what the problem was was bad wiring and a bad connection. I replaced the battery and fuel lines and she cranked. Got it running and sound great. But now the engine is not peeing to cool it. I have idea where to start.

 

[Maxz695]

Re: Help with a '86 Merc. 50HP

more than likely you need to change the impeller in the lower unit esspecially if it,s been sitting for a long time. Do Not Run this engine for more than a few seconds you will damage it find the waterpump kit then drop the lower unit paying attention to where your shifter is I prefer neutral but others argue that fact. after lowering the bottom unit you will see the waterpump on the long shaft.That is what your going to disasemble and rebuild it,s not overly complicated just make sure the pin that goen on the flat of the shaft is there when you slide the impeller onto it this is the key that turns the impeller. bolt it down slide the unit back up align the water tube and up she should go with a little force rebolt and check it in a fake lake (Barrel of water to test you work good luck hope i coved everything

 

[crs0010]

Re: Help with a '86 Merc. 50HP

Changed out the impeller and it is now pumping water. But it is still not coming out of the pee hole. I checked one of the rubber hoses going into the cylinders and water is moving coming into it. It seems like it is clogged inside the block. There is also a small hole where water is coming out near the pistons that i don't think it is supposed to, possibly a safety mechanism, idk or my engine is completely done. Ive also tried running wire/weed eater line up the hoses nothing....

 

[Maxz695]

Re: Help with a '86 Merc. 50HP

your thermostat is more than likely bad. If this engine has one. Take the hose off from where the pisser goes to and back flush it with air or a water hose. I have a 40 horse 2 cyl 2 cycle and the popit above the thermostat with the little hole was leaking indicating the popit diapham had a whole in it being i,m in florida I removed the T Stat and removed the popit then screwed a screw in the popit hole to prevent the water from escaping there. My 40 HP Pisser hose runs from the side oil case to the fuel pump then to the pisser it was clogged so if when you remove the Tstat run water through the engine like normal throgh ears, tub, barrel whatever and see if water is flowing out the popit Thermostat. If so your clogged from there to the pisser. trouble shoot that area

 

[crs0010]

Re: Help with a '86 Merc. 50HP

Need Help. Does anybody know where the thermostat on this model outboard is. I'm having trouble finding it.

 

[G3Joe]

Re: Help with a '86 Merc. 50HP

go to crowley marine an look at the exploded diagrams to find your model. As far as water not coming out, take the rubber hose OFF of the block and be sure there's not a blockage at the END of the Pee hole. On those year mercs, the little rubber gromett at the end of the pee line was smaller than the ID of the hose that comes out of the block. mine was clogged with mud, I was going to replace the impeller, but now don't have to, but since I already bought the part I probably will anyway. Or you could have a bad thermostat of course. One more thing, I ordered a solenoid for my 83 merc 50 and the part number superceded trail indicated a certain part number. When I got the part from e bay, it was the wrong size solenoid. I opted to "rebuild" my originial solenoid, by taking it apart and using an emery board to sand the contacts. Ops check good.