Dead Mercury 115 - NEED HELP

[Fester]

I have a 1985 Mercury 115 Inline 6 with tilt / trim. The lower portion of the block was submerged for 1 day 5 weeks before I bought it. The pistons move freely and I replaced the 2 tilt / trim solenoids and starter solenoid. Being new to fixing these I made a huge mistake and wired the battery to the same side of the solenoid as the starter motor. Huge spark to say the least. I installed all new wiring in the boat and a new ignition. I verified all is correct and the choke solenoid clicks when I push the key in on the ignition but nothing happens when I turn the key.

My main concern is that on top of all of the wiring at the console needing to be replaced I am fearing that the electrical on the motor is also shorted out. I am in need of some guidance as to what I can do to test certain things on the motor to determine what is wrong (stator, starter motor, trigger plate, switch box, etc.).

All of the wiring on the motor has been cleaned and replaced and all fuses have been checked and are OK. The only piece on the motor that I know that HAS to be replaced aside from a new starter solenoid (melted) is a small 1" X 1" black box with 4 little tabs coming out of it at the top of the block that looks like has some wires coming into it from the stator. Can anyone tell me what that is?

Sorry for running on but I want to know what I should test 1st on the motor with a volt / amp meter to see what is not working, fried out, etc. Any information would be helpful and if pictures are needed I can upload them. Let me know and Thanks in advance!

 

[Fester]

Re: Dead Mercury 115 - NEED HELP

Anyone? Any Ideas?

 

[Steves69ss]

Re: Dead Mercury 115 - NEED HELP

Fester, I dont know if I can help or not...If the engine will not crank over lets start there. You said you replaced the starter solinoid, with a helper turning the key to the crank position you need to check for voltage at the small terminal that comes from the switch, if there is voltage check to see if there is voltage on both of the large terminals.[obviously there should be battery voltage on the one that comes from the battery]If you do have voltage on both of the large terminals in the crank position you need to check the power to the starter. If you have power there and it doesnt turn over you need to check and make sure you have a good ground... if the power and ground are good the engine should crank over....dont know if that helps or not...let me know what you find and we can go from there..Steve

 

[Chris1956]

Re: Dead Mercury 115 - NEED HELP

Fester, The first thing to do is to remove the spark plugs and make sure the motor turns over smooth. I would be shocked if the lower bearings are still good.

Next take a compression test. Use a jumper cable to connect the battery to the starter directly. One cable from Neg battery post to the cowling and the other from the pos battery post to the starter. There are two cables on the starter one is ground, so don't mix them up.

Post the compression numbers, and make sure you test the bottom cylinder. if the compression is good, and the motor harness is bad, replace the motor harness. There are tests for all the ign components at the CDI electronics web site. They also sell replacement ign components.