1993 mercury 115 4 cylinder 2 stroke. Turns over won’t start. Pops like it wants to every once in a while. Can’t figure it out

[Texas92]

The boat has good compression on all cylinders. It is getting spark. Getting fuel I believe the carbs have fuel in them took them off checked them they are all clean. I replaced the starter because seemed to be turning over slow now spins fast until I pull the fast idle lever up and then bogs down. I’m at a loss on what to do now

 

[racerone]

You are pushing the key in and holding it in while cranking it over ?

 

[Texas92]

Yes I have tried that but will try again this evening. Thank you I will let you know what it does.

 

[Dave1027]

Did you pump up the primer bulb till firm?

You can check the enrichner this way. With the engine off, turn key on (but not to start. Have somebody push the key while you listen to the enrichner solenoid. It should make a click when the key is pressed.

 

[Texas92]

I think I figured it out the flywheel key was sheered. About to be back to put the new one in will see if that was it.

 

[Texas92]

Did you pump up the primer bulb till firm?

You can check the enrichner this way. With the engine off, turn key on (but not to start. Have somebody push the key while you listen to the enrichner solenoid. It should make a click when the key is pressed.

Yes just checked that as well it’s working

 

[Texas92]

Compression was #1 130 #2 125 #3 125 #4 130

 

[Dave1027]

I think I figured it out the flywheel key was sheered. About to be back to put the new one in will see if that was it.

That will do it. But how did that happen?

 

[Texas92]

I honestly do not know how it happened. When I bought the boat it ran got it home and tried to start it and nothing happened so had to have happened when I tried to start it. But I did replace it and now it started right up and runs like a top. Any ideas on what would have caused that to happen?

 

[racerone]

Someone did not torque the nut properly.-----And there are still some folks out there who think a bit of grease on the taper will make it easier to remove flywheel.----Should be assembled clean and dry.

 

[Texas92]

Alright it’s dry and cleaned it all up to put back together but no grease it’s all dry. Do you know the correct torque for it ?

 

[Dave1027]

Alright it’s dry and cleaned it all up to put back together but no grease it’s all dry. Do you know the correct torque for it ?

My manual states 120 ft/lbs which is pretty stout. Book shows using a flywheel holding tool which latches onto the starter teeth.

 

[Texas92]

Thank y’all so much this is a awesome forum. Anyone have the manual to this thing that I can print out or is that something that is only available to purchase. Want to figure out what the beeping or constant alarms mean so I am aware of it. I started it and there is a constant beep wondering if it’s for the oil I mix in the tank don’t trust the oil idk why my grandpa just told me one time to never trust the oil always mix in the tank. It is down below a 1/4 so maybe is signaling that?

 

[Dave1027]

It's supposed to beep once when you turn the key on. That's the self-test. Constant beeping could be low oil in the oil tank. The warning could also sound for an overheat condition.

There's nothing wrong with the autoblend system on these motors. Mine is still going strong after 30 years

 

[Texas92]

Hmm I may have to try it the looks like some of the hoses may be bad or cracked so I will replace those and see if it oils correctly. And yes it just constant ring not really a beep as soon as it starts up the key does the same thing when it’s turned on

 

[Dave1027]

Yeah. I had to replace all the oil system hoses on my motor some years ago as they all began leaking with age.

I don't remember how much oil needs to be in the tank to keep the alarm from sounding. I'd say fill it half way and try it. You might have a bad level sensor in the tank.

Also, you may have a bad warning module. I replaced mine a long time ago but then the replacement went bad too. When the module goes bad it sounds the alarm continuous. I then converted it to the more basic 3 cylinder setup which does not use a warning module.

 

[Texas92]

Alright I will try that.

 

[Texas92]

Oil level sensor is good. The temp sensor is working. Also unplugged both to see if there was a change and no change one single tone alarm is going off after start up it’s constant.