1995 force 120 hp will not start sometimes

Joined
Jul 8, 2013
Messages
11
I have a 1995 force 120 that runs like new until you get as far from landing as possible it seems like and then it will not start just turns over. i have sprayed starter fluid in to carbs and nothing that makes me think it is not firing. i get towed in and trailer it home and hook the water to it and try to crank it and it starts right up. this had happen to me twice out of the 4 times i have took it out. Dont know what to test because it is running great now. if i go out there now it will crank right up. please help me! thanks, Marc
 

pnwboat

Rear Admiral
Joined
Oct 8, 2007
Messages
4,251
Re: 1995 force 120 hp will not start sometimes

I would take a look at the Kill Switch. Make sure the Kill Switch lanyard is connected properly. If it happens again, try fiddling with the Kill Switch and see if it has any affect. If there is any doubt, you can temporarily disconnect one of the wires from the back of the Kill Switch itself. This will disable the Kill Switch.
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,657
Re: 1995 force 120 hp will not start sometimes

Won't start after you turn it off and let it sit a while?


Sounds like it is time to replace the fuel pump diaphragm.
When the get old, they develop holes, then leak gas directly into the crankcase and flood it out.

Easy and cheap to do. $15.

Get the rebuild kit from a Mercury dealer.

Its a good idea to replace these every 10 years or so, and you motor is 18 years old.
 
Joined
Jul 8, 2013
Messages
11
Re: 1995 force 120 hp will not start sometimes

I turned the lanyaed switch off and on several times to see if it would start out on the water, but i didnt open it up and look at connection. I took out spark plugs and they was a little wet, wiped them off and put them back in. I bought a spark tester today so i will have it if it happens again. I will try to rebuild pump this week, im sure it is due, it has same pump it came with. the motor is all original but the starter.
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,657
Re: 1995 force 120 hp will not start sometimes

let us know what you find.
 
Joined
Jul 8, 2013
Messages
11
Re: 1995 force 120 hp will not start sometimes

Won't start after you turn it off and let it sit a while?


Sounds like it is time to replace the fuel pump diaphragm.
When the get old, they develop holes, then leak gas directly into the crankcase and flood it out.

Easy and cheap to do. $15.

Get the rebuild kit from a Mercury dealer.

Its a good idea to replace these every 10 years or so, and you motor is 18 years old.

I rebuilt fuel pump, there was no holes but the diaphragm was stretched. i bought a universal fuel filter from advanced auto store and put it on in place of stock filter between pump and carbs it is clear and i can see that it is only half full of gas is this normal or should it be completely full of gas while it is running?
 

keithwp

Cadet
Joined
May 1, 2013
Messages
13
Re: 1995 force 120 hp will not start sometimes

I rebuilt fuel pump, there was no holes but the diaphragm was stretched. i bought a universal fuel filter from advanced auto store and put it on in place of stock filter between pump and carbs it is clear and i can see that it is only half full of gas is this normal or should it be completely full of gas while it is running?

Did you ever figure out the problem?
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,817
Re: 1995 force 120 hp will not start sometimes

Just a reminder, this is an old post revived by Keithwp whom I believe have the same problem. Keith if my speculation is correct, you are more than welcome to start your own thread and maybe if resolved will be thankful enough to post your success story for others to see and relate.
 
Joined
Jul 8, 2013
Messages
11
Sorry i did not reply when i fixed problem last year. It was the switch box. It would quit working when it got hot after running motor down the lake awhile.
 
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