1980 Mercury 115hp help!

[keith1377]

I have a 1980 115hp inline 6 cylinder. Boat motor is missing and when put under a load (in the water in gear ) it bogs down and wants to die out. I checked the compression and it is 145-150 psi in all cylinders. Cylinder #1 has no spark, and cylinder #6 has a weak spark. All other cylinders have a hot blue spark. Im thinking it is an ignition coil, but havent had time to switch with another cylinder that is firing. Also the rectifier had two wires on it that the insulation melted off. I put liquid electrical tape on the exposed area. Should i replace the rectifier? Anyone plz help. The fuel bulb is rock hard, so it seems to be getting plenty of fuel.

 

[keith1377]

Re: 1980 Mercury 115hp help!

Also a guy told me that the speed control linkage is out of adjustment. I just went to the library and got a service manual. Hopefully that will help me along somewhat.

 

[daveswaves]

Re: 1980 Mercury 115hp help!

I have a 1980 115hp inline 6 cylinder. Boat motor is missing and when put under a load (in the water in gear ) it bogs down and wants to die out. I checked the compression and it is 145-150 psi in all cylinders. Cylinder #1 has no spark, and cylinder #6 has a weak spark. All other cylinders have a hot blue spark. Im thinking it is an ignition coil, but havent had time to switch with another cylinder that is firing. Also the rectifier had two wires on it that the insulation melted off. I put liquid electrical tape on the exposed area. Should i replace the rectifier? Anyone plz help. The fuel bulb is rock hard, so it seems to be getting plenty of fuel.

Just switch the wires for 2 adjacent coils, if the problem follows the wires it is a bad switchbox, if it stays with the coil...its the coil. The procedure that the fellow was talking about is a link and sync. If you have had the carbs off to clean them it will need to be done. If the motor is new to you it is worthwhile checking. Nothing can be done until you fix the no spark problem. Your compression is good.

 

[keith1377]

Re: 1980 Mercury 115hp help!

Thanks for the reply. much appreciated.

 

[Chris1956]

Re: 1980 Mercury 115hp help!

That is also a symptom of a dirty or misadjusted carb. Were the carbs worked on or has the motor sat around a lot? Straighten out the spark, and if that dosen't fix it, suspect the carbs.

 

[keith1377]

Re: 1980 Mercury 115hp help!

ok, i worked on it a little this week. the problem stayed with the coil packs for the #1 and #6 cylinder when i switched the wires. Can i replace just the two bad coil packs, or do you have to replace all 6 so they are all the same?

 

[richard1969]

Re: 1980 Mercury 115hp help!

Hi Keith, just come across your post and maybe able to help. I come across the same problem after buying my boat 3 years ago with a merc 115hp 6 cylinder brown band. Tried lots of things then took it for a service and they found it out to be a faulty stator which i replaced at a cost of ?250. Since then the engine has run perfectly. hope this helps. Richard.