1989 70 hp mercury cylnders kick in and out

[len mitchum]

I have a 1989 mercury outboard that runs great at times and then runs on one cylnder or two cylnders at times. I found two coils with the magnets cracked, so I replaced them, thoght that was it, but next trip out, it did it again. Sometimes it will run great for a while then drop a cylender or two. Other times it will run bad, then after idling for a few minutes, just pick up and run great. It never wants to start without a little squirt of starting fluid. I've tried to use the choak, but it does nothing, will only start with starter fluid the first time, which I was just told I should never use on a 2 stroke. once it starts, it will crank right up with out starter fluide, unless it sits for a couple of hours. I just replaced plugs, and completly cleaned all the carbs, but no differance. I think maybe it could be the switchbox, the trigger or both. I've unhooked the trigger from switchbox and ohmed it out with a meter, but never got a good reading? Thought if I just buy new switchbox, trigger, and even stater, that would do it, just hate to buy parts for nothing. Can anyone help me with this, tell me what ro check and how to check it. Thanks, Len

 

[westexasrepublic]

Re: 1989 70 hp mercury cylnders kick in and out

check your wires, mine had a similiar problem, all the wires from the wiring harness where badly corroded and arking on other wires, the case was the same with my trigger and stator. I was able to make a new wiring harness, but order new stator and trigger.

 

[len mitchum]

Re: 1989 70 hp mercury cylnders kick in and out

Thanks, I tried to get the flywheel off with out the right tool and did not work, I'm taking it to the shop where they are going to take the flywheel off for me for $10.00. then I will be able to check for bad wires.

 

[divinginn]

Re: 1989 70 hp mercury cylnders kick in and out

I just finished fixing mine,it was doing the same thing. I had a plugged elbow fitting that screws in the carb,also a weak fuel pump,replaced the diaphragm in it. Hopefully that is all that is wrong with it.

 

[len mitchum]

Re: 1989 70 hp mercury cylnders kick in and out

just got back from shop. Mechanic took the flywheel off for ten dollors. Took the stater and trigger off and wires were in perfect condition by appearance. the guy at the shop told me that the number 1 cause of problems for boats is bad battery connections, hand tight battery twist on connectors are not good. He told me that it was probably the switchbox or the stater. He said that triggers rarely go out. I've seen that they are making the switchboxes with plastic casings to prevent arching inside. I wonder if I take my old switchbox, turn it upside down, heat the metal casing with a low tourch flame to release it from the casing and then silicone it back in place. I will buy a new switchbox, but what if that is all that is wrong. the black jell insulation cracked open on the inside allowing it to arch to the metal casing. HUMMMM!!!!!!

 

[dvilla]

Re: 1989 70 hp mercury cylnders kick in and out

Hey there. So did you come to a conclusion with this problem? I am fighting the same thing. Typically, I have one cylinder that occasionally stops firing. Fuel system working fine, just changed the coil(had a broken magnet) and it still isn't working right. Now looking for the next step. The parts are getting more expensive and I hate to just keep buying parts.

 

[westexasrepublic]

Re: 1989 70 hp mercury cylnders kick in and out

http://www.youtube.com/watch?v=GP7n...aBB.pl?num=1175227246&feature=player_embedded

watch this vid for testing your electrical...