1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

Please bear with me while I explain all the details. So I have been working on restoring a 1984 4 Winns Catalina since about April. When I got the "free" boat it had sat outside for about 5 years. I started with replacing the entire interior from the fiberglass floor up. At that time I thought the motor ran fine. I hooked it up to a battery and after a few minutes it fired up. So I left it alone while I worked on appearance.

The first time we took it out to the lake it ran for about 8-10 mins. no problems. I put it in neutral for about 30 seconds started to accelerate and the engine made a bogging down noise and stalled. I got it restarted ran fine in neutral, put it in drive and it bogged down and stalled. That was it for the day. Wouldn't start after that.

I brought it home, replaced all the fuel, replaced all the spark plugs, cleaned out the fuel filter and sprayed out the carbs with carb cleaner. It ran in the driveway, but the throttle had to be push up to get it started. It acts like it is not getting enough fuel. After running for a few minutes it warms up and can be taken back to neutral and runs fine.

We take it back to the lake. Boat starts, put it in drive and it stalls. Repeat a few times, same result. Boat stalls under load.

Come home and I rebuild both carbs. Boat runs in drive, but still have to throttle up to start and in neutral acts like not enough fuel. I noticed last night that one of the wires from the stator to the switcher board is destroyed. Rotted away to dust.

Can that have anything to do with the engine problem? I am open to ideas and at a bit of a loss. This is my last effort before I have to take it somewhere or call it quits for the season. Please help, I will be very grateful.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

more than likly you are going to need to replace stator, triger,voltage reg and one or more of the switch boxs. if the wiring is rotted to one likly rott to all. your likly to be ok . now you have to check all wiring from ing, control to motor. if you don't you may burn some else up . You MUST rebuild water plump,it's a must. if you read forums you will fine many places to buy what you need at a good price ones your motor is repair it' going be great and last a long time. have fun

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

I forgot to mention that the first motor repair I did to this engine was replace the impeller and oil change.

Oddly enough the other wires in the bundle seem to be sound. I noticed that the green wires are the only wires that have corrosion and the plastic casing cracking off.

Would the stator cause the engine running issues? Or do I need to adjust the carbs? Thank you for your help.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

barefiel76 said:

I forgot to mention that the first motor repair I did to this engine was replace the impeller and oil change.

Oddly enough the other wires in the bundle seem to be sound. I noticed that the green wires are the only wires that have corrosion and the plastic casing cracking off.

Would the stator cause the engine running issues? Or do I need to adjust the carbs? Thank you for your help.

Click to expand...

yes it will cause it not to run right it and the triger tell the switch boxs when to fire spark plugs. stator trigger switch boxs and coil all work toghter

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

How about splicing/soldering in new wires instead of replacing expensive components?

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

I have sliced in some wore to fix some of my wiring on my old 1983 50 HP. make sure you use GOOD, flexible wire. It will be trial and error.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

I tried adjusting the carbs following the guide I found on the boat forum. The motor will start and runs ok. I got it to sounding pretty smooth, but it only runs for a minute or two and stalls.

I will try to solder in some replacement wires. i am hoping that will help. Again thank you for the advice and ideas.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

Runs for a minute and stall sounds like maybe fuel pump or fuel tank vent problem to me.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

Dave is right about fuel pump and venting ! But if you are going out on one of great lakes with a motor you soider bad wire to good , your more of a man than me . I'm all for saving a dollar but I'm not willing to get help 4 miles out!!!!!
QUOTE=barefiel76;3954657]I forgot to mention that the first motor repair I did to this engine was replace the impeller and oil change.

Oddly enough the other wires in the bundle seem to be sound. I noticed that the green wires are the only wires that have corrosion and the plastic casing cracking off.

Would the stator cause the engine running issues? Or do I need to adjust the carbs? Thank you for your help.[/QUOTE]

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

I agree with the decision to do it right the first time. I ordered a new stator which arrived today. I found a marina close by the house and they pulled the flywheel for me, $20. What does the Trigger plate assembly do? I have 1 wire that has turned to dust coming out of it.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

The trigger is the timing. It tells the switchbox when to send the voltage from the stator to the coils which fire the spark plugs.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

OK so not to beat a dead horse, but..... I'm going to ask anyway. A broken wire coming out of the trigger would not have the spark plugs firing in order. So this could be the reason the motor runs for a about a minute or two and slowly stalls out? I have found some wires that should be replaced, but it is driving me crazy not knowing where the specific issue is coming from.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

Yes. It could be the reason. It's easier to do the fuel system first. Replacing trigger is a more involved job that requires pulling the flywheel.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

I replaced the stator and a broken wire coming out of the trigger. I have found that if the throttle is disengaged and pushed forward the motor will start but only for a minute or two at around 2000 rpms. If I put it in neutral the motor wont start or stalls out. Are there any new ideas? Thanks.

Re: 1984 Mercury outboard 75hp issues. Please help. I would really appreciate it.

Disconnect the wiring harness from the engine (THE BIG PLUG) Turn the key and start he engine. Retest for starting in neutral. See if it stays running in drive. If everything checks out the problemj is in the shifter more than likely the mechanisin for the saftey neutral switch. or the lanyard switch i8f you have one. It is more than likely with the plug undone to have to jump the solenoid with a screwdriver to get it to start. This will eliminate any thing in the boat that would cause a problem with the motor itself