1986 Mercury 115 "tower of power" questions

[DustinG]

Hey everybody! I picked up a sweet project boat...for free! It came with a 1986 Mercury 115 inline 6cyl motor. I know the impeller is stuck and needs to be replaced, but also there are a couple of wires coming from beneath the flywheel that are corroded off. The motor isn't locked up, but won't turn over. It's been sitting for a while. Does anyone have any suggestions on what steps to take next in order to get her ready to run?



Is there some sort of a cover missing here?



The guts



Here are the two corroded wires I mentioned



Nifty little stand I built last week



Thanks for looking!! Looking forward to any advice from you guys!

 

[Dave1027]

Re: 1986 Mercury 115 "tower of power" questions

For free???!!! Awesome. Even comes with a nice SS prop too.

I think the first thing to do is a compression test to get an idea of what you have before spending any more time on it.

 

[njrextreme]

Re: 1986 Mercury 115 "tower of power" questions

You are missing the the cover that goes on the front that covers the latches. The wires that are broke are coming off your rectifire. That switches power from ac/ to dc for charging your batt. You will need to take off your flywheel and take a look at the trigger and stator under it. I have a one time used complete ignition system off a 86 Mariner 90 inline. Same motor as a Merc. I replaced everthing new and then The motor started knocking the first time out w/ it. Im not sure if the 115 has the same parts but it prob does. Let me know if you need any parts. I have the cover for the front also but its mariner not merc. You could paint it black and use it.

 

[DustinG]

Re: 1986 Mercury 115 "tower of power" questions

You are missing the the cover that goes on the front that covers the latches. The wires that are broke are coming off your rectifire. That switches power from ac/ to dc for charging your batt. You will need to take off your flywheel and take a look at the trigger and stator under it. I have a one time used complete ignition system off a 86 Mariner 90 inline. Same motor as a Merc. I replaced everthing new and then The motor started knocking the first time out w/ it. Im not sure if the 115 has the same parts but it prob does. Let me know if you need any parts. I have the cover for the front also but its mariner not merc. You could paint it black and use it.

njr I'm going to check on the cover and see if it would work for my engine...I'll get back to ya on that!

 

[JDusza]

Re: 1986 Mercury 115 "tower of power" questions

Yup. Yup. Agree with all. Good deal.
You have a few things to do. I recommend you check the Top Secret File.
The corroded wires are from the stator running to the rectifier. They should be repaired. You do not need them to troubleshoot or start, but you do need them to charge the battery. You may end up taking them off to troubleshoot ignition issues.

Engine won't turn over? Not sure what you mean; the starter will not spin the crank or the engine will not start?
Once the starter spins the crank: compression, spark, timing, fuel. Vroom!

Check compression; you're looking for >90 psi within 10% across all six.

Check spark with air gap spark tester; look for 3/8" air gap jump.
Based on the wires, I'd say the stator is in question. Ignition trouble-shooting isn't tough, it is just time consuming. For ignition trouble-shooting help, refer to cdiignition.com / Support / Troubleshooting.

After compression and spark, you need to add fuel and ensure the spark is timed right.
Check / change the lower unit oil before you do the impeller so if the seal needs changing, you're in there once. Same with water tube grommet.
J

 

[mr 88]

Re: 1986 Mercury 115 "tower of power" questions

As far as the wires go,why not splice some new ones in from just the break point. The exposed wires do not look corroded,more like the wrap or something was rubbing on that spot. Just use some quality heat shrink connectors and the same gauge wire.

 

[DustinG]

Re: 1986 Mercury 115 "tower of power" questions

That's a good idea, it would be a LOT cheaper than just randomly replacing a stator or trigger assembly. I suppose I should troubleshoot the ignition system also to determine if anything or everything needs replacing!