need help with 1975 115 hp mercury power trim and tilt

tbone1987 · Apr 3, 2011

i just bought a skeeter wrangler bass boat with this 1975 mercury motor. the key is broke off in the ingnition and i have to go grab a battery tommarrow to start seeing whats what. the boat hasnt been ran for 3 years and been sitting outside. the motor of the trim and tilt is all the way down and i hauled it home that way.

Questions-
gas mix?
how could i bypass the broken ignition and get the motor to fire?
can i wrap a rope around this flywheel and start this big boy?
what should i do before i try and start?
I need any info some1 could give about this motor and i would greatly appreciate it. ill put pics up tommarow and let everyone see my new bass hunting machine.
thanks to all who reply

daveswaves · Apr 3, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

tbone1987 said:
i just bought a skeeter wrangler bass boat with this 1975 mercury motor. the key is broke off in the ingnition and i have to go grab a battery tommarrow to start seeing whats what. the boat hasnt been ran for 3 years and been sitting outside. the motor of the trim and tilt is all the way down and i hauled it home that way.

Questions-
gas mix?
how could i bypass the broken ignition and get the motor to fire?
can i wrap a rope around this flywheel and start this big boy?
what should i do before i try and start?
I need any info some1 could give about this motor and i would greatly appreciate it. ill put pics up tommarow and let everyone see my new bass hunting machine.
thanks to all who reply

Before you start putting a battery on it check and repair the wiring harness in the engine, the insulation will be rotten and can easily short. Pull the spark plugs and put some marvel mystery oil in the cyl or penetrating oil and see if you can turn the engine by the flywheel, you may have to put a wrench on the crankshaft nut to get levereage. It should move easily, if it does not the rings may be rusted to the cyl walls. If you can move it freely and you have checked the wires you can connect the battery and do a compression check. Post the results and we can go from there. The broken key is not a problem, if you take apart the controll box you will see the key number marked on the back of the ignition switch, it will be a 2 digit number. You can get a new key from your merc dealer.

tbone1987 · Apr 3, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

i can turn the motor by hand. not easy so i think the compression is good. ill test it tommarow though. ill pull all three carbs and give em a good cleaning. do i have to mix this fuel? ratio? is this a problem motor? it seems like it was taken care of befor the 3 yrs of weather damage. said it was supposed to run. im pretty sure it will run. i just gotta figure out the wireing and stuff. i tryed to stick the broken key in the ignition. couldnt really get it to turn. ive never had a console steer boat that i had to work on. are these ignitions tricky? im gonna attach a pic of boat. ill get pic of motor tommarow. thanks again

aussieflash · Apr 4, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

Make sure you clean the tank as well.If it's oil injected I would disconnect pump and run remote tank of 50-1 litre,till you know if the pump works.Clean everything filters etc.You can start motor from solenoid and starter kit from auto shop.
Good Luck.Paul

Chris1956 · Apr 4, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

Gas-oil mix i 50::1. There is no oil injection on that motor. Use some strong tweezers to pull broken key out. Alternatively you will need to get a new ign switch and solder it in.

The motor is very easy to hot wire, but inspect the engine wiring as they are usually in bad shape by now. Distributor rotor is non removeable and fragile. Dist cap is very expensive to replace.

Post back when you have the carbs cleaned, the gear oil changed and the engine wiring is good, and i will tell you how to hot wire it.

tbone1987 · Apr 4, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

thanks guys. i didnt get a chance to do much but get some pics of the boat and motor. ill post this project as i complete. carpet and decks to fix as well. im going to rteplace wireing soon and try and fire this thing up. here are some pics......i got this boat and motor and trailor with all 3 titles for 600$$$

tbone1987 · Apr 4, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

any1 have a manuel for this tower of power???

merc850 · Apr 4, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

Great Deal! Before you try to run it replace the waterpump impeller 5 seconds of running to test it for starting is OK.
View attachment 88480 Wiring Diagram.
That motor runs 50:1 mixed fuel and I would recommend Quicksilver or Amsoil.
(I run my 1975 850 at 75:1 Amsoil.

Mi duckdown · Apr 4, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

600 bucks? deal of the century.
Buy an OEM Merc Manual for that motor.
Since you stole that boat. another 100 bucks for the repair/service manual would be well worth it.

tbone1987 · Apr 4, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

ya i think i got a steal. just hope the motor is ok. gonna replace carpet soon. any suggestions on how to make that paint shine again? wax? its a black with red flake paint. can i restore???

aussieflash · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

Was that deal made at gunpoint?I think I payed too much for mine now.Try a light cut n polish and see how she goes.Good luck

bigdaddy08302 · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

Im looking at a 85 merc 115 straight 6 now....owner says it ran last season but it is no longer on the boat..asking 500 for the motor...think its worth a chance? No practical way to do much checking at the current owners house...no motor stand etc.

tbone1987 · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

not sure big daddy. i wish i knew more about this motor myself but thers only 1 way to learn and thats to jump in and get started. im going over today my shop today and gonna replace any bad wires in the engine and buy a battery. im gonna want to do a compression test later this afternoon.(after i clean tank and replace wires, fresh oil.) chris1956 could you please let me know the hotwire procedure. im gonna put a full day in on this boat so ill be ready for test fire today. thanks every1.

douglas1978 · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

tower of power motors are great motors i like the inlines i have 1974 115 with tnt paid 500 bucks for it has 145 comp on each cyl. Had it out on the water last wed ran like a top

tbone1987 · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

just in case you guys are curious. this is the 600 dollar boat i traded for the skeeter. i got this bout for500, motor for 100(needed impeller), had 1bout 60 dollars worth of carpet and wood rebuilding the decks. i i had no intetions of keeping this boat. just figured i could make some cash since its starting to get warm here in illinois.

Chris1956 · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

tbone, After the engine wiring is in good shape or replaced, if the ign switch is still inoperable, you can hot wire it like this.

Connect a fully charged battery to the boat wiring harness. Connect up a fresh tank of 50::1 mixed fuel. Pump primer to fill carbs with fuel. Remove cowl, and pull manual choke knob straight up. (manual choke is black knob on top of front cowl support.) Carb shutters will close. Set cold start lever all the way up on Mercontrol. Install water flusher device and turn on the water 3/4 of the way. Now connect clip lead from red wire connection on starboard side of switchbox to white wire connection directly next to it. This powers ignition. Now use clip lead from red battery cable on starter solenoid to small yellow wire connection on solenoid. This will crank motor. If it starts, remove the solenoid jumper and feather the choke until it warms up.

dwco5051 · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

You are going to love that motor when you get it running. There are some things that just sound perfect to the human ear. Like birds singing in the morning, old Patsy Cline records, and a six cylinder Merc inline running up the lake flat out.

daveswaves · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

dwco5051 said:
You are going to love that motor when you get it running. There are some things that just sound perfect to the human ear. Like birds singing in the morning, old Patsy Cline records, and a six cylinder Merc inline running up the lake flat out.

I go out walking, after midnight
Out in the moonlight
i'm always walking, after midnight
Searching for Mercs

tbone1987 · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

well i got all the wires ran but hey were so far gone i couldnt really tell the colors. i just replaced them 1 at a time and hooked them all back up.

now i tryed this hotwireing technique but i cant really go by color. i need to know where to hook the wires. not sure what the switchbox is????? think i know which is the selinoid but i took some pics and decided to ask the pros........... any suggestions

tbone1987 · Apr 5, 2011

Re: need help with 1975 115 hp mercury power trim and tilt

oh and i tryed to test spark while i had it jumped withthe emergency pull rope. had nothing...........this is because the the ignition wasnt hot right????

need help with 1975 115 hp mercury power trim and tilt

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